B109: Home range and habitat selection of Brown Eared-Pheasant in the spring. Zhang Z.W., Zeng H.M. & Zheng, G.M.

Abdulla, E.V. & Shukkur, E.A.A. 1998. Feeding ecology and population dynamics of Purple Moorhen, Porphyrio porphyrio. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 274

Purple Moorhen was a very abundant pest bird of paddy especially of the local ‘Kuttadan’ variety. It was netted and hunted heavily for meat and chased by farmers by using firecrackers. Its population is now showing symptoms of decline. Nevertheless, its ecology and food habits are not well understood. We studied the population status and dietary preferences of Purple Moorhen in the Wetlands of North Kerala from 1979 to 1997 based on weekly counts and field observations. The bird is now very rare in several jheels where the population used to occur in hundreds decades back. ‘Kuttadan’ variety of paddy cultivation is abandoned by farmers because of Moorhen infestation. The Kariba Weed Salvinia molusta and Water Hyacinth Eichhornis crassipes have colonized almost all the wet and marsh lands of Kerala and in some jheels of zero hunting pressure the bird increased in population and did not feed on paddy. The bird does not seem a real pest and seems to feed on paddy only on occasions when weeds are not available. The summer nomadism of the bird in search of wetlands has increased along with heavy summer mortality.

Key words: agriculture, pest, management, foraging

 

Adkisson, C. S. 1998. Ecology of acorn dispersal by Blue Jays in Florida, USA. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 274

Blue Jays Cyanocitta cristata inhabit the eastern deciduous forest of North America, where they cache large numbers of acorns, beechnuts, and chestnuts during September and October for use during the following winter and early spring. Earlier studies showed that as many as 3000 nuts may be cached by each jay. Not all nuts are consumed, and many germinate in microhabitats highly favourable to seedlings of Fagaceae. At the southern end of the Lake Wales Ridge near the Archbold Biological Station most of the native scrub habitat has been replaced by citrus groves and other uses. Unlike most of the native biota of the region, Blue Jays thrive in a variety of habitats, as long as patches of oak woods are still present near their home range. In addition to nesting in towns, woodlands and edges, the jays also nest in citrus groves near the woods. Up to 300 bird-trips/hr from an oak woods into a grove have been documented. The jays that breed in groves cache acorns in their home ranges in the citrus, with the total caching effort of each pair of adults estimated to be as much as 10,000 per caching season. The ecological impact of this caching is minimal as long as the grove is cultivated, but many Florida groves have been abandoned since 1980, due to development pressures and adverse weather, and dying groves often become heavily colonised by oaks, exclusively through the activity of Blue Jays. This corvid is the only agent of long distance dispersal of acorns in eastern North America, and is apparently the primary influence in the re-establishment of oaks in disturbed habitats in central and southern Florida.

Key words: Blue Jay, oaks, seed dispersal, recolonization, seed catching

 

Adriaensen, F., van Dongen, S., Lens, L., Matthysen, E. & Dhondt, A.A. 1998. The weight of Blue Tits in the presence of sparrowhawks. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 275.

Small birds increase fat reserves in winter as insurance against reduced and unpredictable food supplies. But, since extra weight effects manoeuvrability, this is an extra risk in terms of predation by Eurasian Sparrowhawks Accipiter nisus. So, optimal winter body mass is a compromise, balancing the risk of starvation and the risk of predation. If weight is important for adult Great Tits Parus major during the winter period, we wondered what this could mean for the fledging weight of young birds, inexperienced and with flight feathers still growing. Fledging weight is a crucial issue, since it is one of the best predictors of future survival chances of a young bird. Since 1979 we have studied Blue Tits Parus caeruleus and Great Tits breeding in nestboxes in several study sites in northern Belgium. At one study site, an isolated plot with a super abundance of small holed boxes and a high density of Blue Tits, sparrowhawks settled in 1990. We will present data on the effect of the presence of sparrowhawks on the weight of adult and fledgling Blue Tits. We will show that Blue Tits adaptively lower fledgling body mass in the presence of sparrowhawks.

Key words: behavioural ecology, body mass, predation, Parus, Accipiter

 

Anjos, L. dos. 1998. Bird communities in remnant woodlots and forest patches in southern Brazil. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 276.

The avifauna structure of remnant woodlots (result of anthropogenic action in a continuous forest) was compared with that of natural forest patches. Sampling was carried out using point counts monthly during one year in four remnant woodlots (660 ha; 56 ha; 25 ha; 7 ha) and four forest patches (840 ha; 40 ha; 20 ha; 8.5 ha). The similarity index (Simpson) between remnants (180 species) and patches (166 species) was 73%. The number of species decreased with area size faster in patches (135; 121; 98; 83) than in remnants (125; 120; 110; 101). The number of frugivorous species that include seeds in the diet was similar in all patches but increased with a decrease in area in remnants. The number of specialised frugivorous species decreased faster in remnants, especially large birds, than in patches. The number of insectivorous and omnivorous species decreased with decrease in area in remnants and in patches; however the abundance of trunk and twig insectivorous individuals increased with the decrease of area of patches only (density compensation). The effect of area size on the bird communities was different between remnants and patches.

Key words: communities, remnants, forest, southern Brazil

 

Anderson, J.G.T. 1998. Habitat utilisation in a mixed-species seabird colony: Responses to changes in vegetation. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 276.

Petit Manan, a three hectare island located in the Gulf of Maine in the northeastern United States is a nesting site for Common, Arctic, and Roseate Terns (genus Sterna), Laughing Gulls Larus atricilla, Black Guillemots Cepphus grylle, Atlantic Puffins Fratercula arctica and Leach's Storm Petrels Oceanodroma leucorhoa. Nesting sites of each species are concentrated in discrete areas, although some overlap does occur. The distribution of nests, vegetation, and other substrate material has been recorded annually since 1991, and entered into a Geographic Information System (GIS). Changes in vegetation height and composition are related to a gradual spread of Laughing Gulls into previously unoccupied areas and an increased concentration of Arctic and Common Terns in peripheral habitat. Experimental manipulation of vegetation has partially reversed this trend, but may negatively impact other nesting species. Use of Global Positioning Systems (GPS) coupled with GIS mapping has permitted real-time comparisons of habitat utilisation within and between breeding seasons, and closer monitoring of management efforts.

Key words: terns, nesting, site selection, GIS

 

Baldi, A. 1998. Effects of reedbed edges on distribution of birds: The role of microclimate, vegetation structure and predation. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 277.

As fragmentation of natural habitats proceeds, the role of habitat edges on the occurrence and abundance of species became more and more pronounced. In this study we censured birds in a water reedbed edge at Lake Velence, Hungary. We estimated the distance of the observed individuals from the edge within the 0-20 m zone. We measured microclimate (air and ground temperature, humidity, wind, light) and vegetation structure (density and height of last year and new sprouting reed, number of nodes and leaves, diameter of reed stems) across the edge. Predation was assessed using artificial nests. Sixty percent of bird observations were within 5m from the edge. The Bearded Parrotbill Panurus biarmicus and the Eurasian Reed-Warbler Acrocephalus scirpaceus showed significant preference for this 0-5 m zone, which is characterised by very dense, thin and short reed stems. Vegetation in the 5-10 m zone was not so dense, but high and thick, further inside both density and size of reeds declined. A possible hypothesis for the edge preference may be the avoidance of predation: our nest predation experiment with 60 nests showed that predation rate was smaller in the edge (35%), than in the interior reed-bed (85% and 50% in sparse and dense reed stands).

Key words: edge-effect, passerine bird community, nest predation, Panurus biarmicus, Acrocephalus scirpaceus

 

Baumann, S. 1998. Where have all the orioles gone? Ecology of Oriolus Oriolus in their resting area. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 277.

The Eurasian Golden-Oriole winters regularly in Southern Africa. The quantitative comparison of habitat parameters in breeding and wintering areas shows differences in the general structure of the habitat (density: P < 0.001;% crown cover: P < 0.01; vertical distribution of leaves: P < 0.001; maximal height of vegetation: P < 0.05; stratum of maximal cover: P < 0.01) but not in respect of the specific characters used by the bird (height of trees used, horizontal and vertical position in this trees). When O. Oriolus arrives, the African oriole species O. auratus and O. larvatus are breeding in the same habitat. The analysis of habitat structure, feeding behavior and interspecific behavior shows an ecological separation of the Eurasian Golden-Oriole and the African Black-headed Oriole while the data of O. oriolus and O. auratus overlap. The dominant African Golden-Oriole often does not tolerate O. oriolus in its breeding territory, however all three species of orioles can be seen together in mixed species flocks after breeding. The ecology of O. oriolus in its winter quarters may be characterized by the choice of a seasonal habitat, local movements often correlated with rainfall, and the use of seasonal available, superabundant food resources like leaf-eating caterpillars and fruits.

Key words: interspecific competition, habitat, Oriolus auratus, Oriolus larvatus, Africa

 

Burger, A.E. & Davoren, G.K. 1998. Interactions among seabirds, prey and ocean features off southwestern Vancouver Island, Canada. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 279.

The effects of biological and physical oceanic factors on seabirds need to be understood to assess impacts and risks of oil spills, fisheries, and natural phenomena such as El Ninó. We investigated these interactions off south-western Vancouver Island, British Columbia, a productive and physically dynamic area which supports high densities of seabirds, and has high risk of oil spills. Over 3-6 years, we repeatedly sampled a 145 km transect over the broad continental shelf, and two nearshore transects 21 and 67 km long. Seabird densities were compared with sea surface temperatures, salinity, relative prey abundance and bottom topography at coarse (>10 km; monthly means) through fine (100 m; 20 s) scales. Over the shelf, the seasonal presence of hake trawlers strongly affected surface-feeding shearwaters, fulmars and gulls but not diving birds (alcids and cormorants). Concentrations of both guilds were sometimes, but not invariably, associated with fine-scaled thermosalinity fronts and prey patches. The highest bird densities occurred in shallow shelf areas (50-80 m deep) adjacent to the Juan de Fuca gyre. Bird-prey associations were weaker when prey densities were high, and in the late afternoon and evening when birds were not actively foraging.

Key words: seabirds, predator-prey, oceanography, Vancouver Island, Alcidae

 

1Centre of Wildlife & Ornithology, Aligarh Muslim University, Aligarh, U.P India, e-mail envis@bnhs.wiprobt.ems.vsnl.net.in; ²SIS, P.O.Box 48, Chocorua,NH 03817,USA.,³Bombay Natural History Society, Hornbill House, Bombay 400023, India; ⁴Centre Of Wildlife &Ornithology, A.M.U., Aligarh, India

Singha, H., Coulter, M.C., Rahmani, A.R. & Javed, S. 1998. Nesting ecology of Greater Adjutant Stork Leptoptilos dubius in Assam, India. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 279.

The Greater Adjutant Stork is the most endangered stork world-wide. Ecological information is scanty. An extensive survey was carried out throughout Assam, India during the breeding season of 1994-95 followed by an intensive study in Nagaon during the 1995-96 and 1996-97 breeding seasons. During the survey we counted 71 nests on 29 nesting trees in nine colonies and compared these results with those of the intensive study. In Nagaon, we counted 51 nests on 20 trees and 52 nests on 18 trees in two years. Nesting trees differed significantly from trees not used in height, dbh and canopy cover (P < 0.001). The number per trees differed significantly according to species (p < 0.001). These conclusions were supported by the results from the larger survey.

Cucco, M. & Woolfenden, G.E. 1998. Daily variation in body mass of the Florida Scrub-Jay Aphelocoma coerulescens during breeding. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 280.

In contrast to many temperate and migratory birds, body mass of the subtropical Florida Scrub-Jay remained stable during the stages of the breeding season, regardless of the individuals' reproductive status (breeding male, breeding female, prebreeding helper). Similarly, despite strong sexual division of labour and a rigid dominance system, daily mass fluctuations in each of the reproductive groups did not differ significantly. Daily body mass fluctuations were synchronised among jays in the population and between individuals living in the same territory; body mass increased from morning to afternoon. Changes in mass were balanced by an opposite change on the following day. Of the five short- and two long- term climatic factors evaluated, those most relevant to daily body mass variation were maximum daily temperature and maximum temperature of a day plus that of the previous day. Jays lost more mass during days with lower temperatures. A proximate (short-term) control of body mass is likely to be at work in this species.

Key words: breeding, Scrub Jay, body mass, temperature, daily variation

 

Curry, R.L., Walton, L.M., Bowman, R., Woolfenden, G.E. & Fitzpatrick, J.W. 1998. Patterns and consequences of nest-site selection in Florida Scrub-Jays Aphelocoma coerulescens. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 280.

Because predation is a primary cause of nest failure and habitat characteristics may influence predation risk, we may expect birds to be selective in choosing nest-sites. We studied nest-site selection and success in Florida Scrub-Jays in periodically burned habitat and nearby fragmented, overgrown habitat, using comparison between nest-sites and background habitat as well as landscape-scale analysis using GIS. Jays in periodically burned habitat nested disproportionately often in oak-dominated patches, in particular oaks, and in concealed sites often associated with vines. Nests in patches of moderate height, in certain shrub species, and with concealment and vines were most often successful; habitat type did not correlate directly with success. Patterns were similar overall in overgrown habitat: Despite taller vegetation and correspondingly greater nest height, jays had otherwise similar nest-sites and levels of success as those in frequently burned habitat. Habitat changes following fragmentation and fire suppression therefore usually do not have major impacts on Florida Scrub-Jay nest success through alteration of nest-site characteristics.

Key words: nest-site, Florida Scrub-Jay, fragmentation, predation, nest success

 

Cuthbert, R.J. and Davis, L.S.. 1998. Delayed reproduction, adult body condition and parental effort of Hutton's Shearwater Puffinus huttoni. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 280.

Hutton's Shearwaters breed at 1300 to 1800m in the Kaikoura mountains of New Zealand. Late snows can delay breeding of some birds by up to a month, the affect of this on adult body condition and subsequent parental effort and breeding success is unknown. Two colonies were selected, one early and one late (median laying date 22 days apart). For each study area the condition (mass scaled for body size) of both partners of 40 pairs was followed over the season. The mean body condition of adults in the late colony was significantly lower (p < 0.01) at laying than the birds in the early colony A greater number of pairs did not start breeding and incubation success was lower in the late colony (p < 0.05). There was no difference in chick mass at hatching, chick growth and adult body condition of pairs that decided to breed, between the two colonies. Delayed breeding appears to cause a reduction in adult condition, such that a minimum condition is met where a pair will decide not to breed or desert early in incubation. Delayed pairs that do breed are able to do so because of a high body condition at the start of the breeding season and their breeding success and chick growth is unaffected.

Key words: breeding biology, New Zealand, body condition, parental effect

Agricultural University of Norway, Department of Biology and Nature Conservation, PO Box 5014, N-1432 Aas, Norway e-mail svein.dale@ibn.nlh.no

Dale, S. & Olsen, B.F. 1998. Different breeding and feeding habitats of Ortolan Buntings Emberiza hortulana in Norway. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 281.

The Ortolan Bunting is an endangered bird species in Norway, and less than 150 pairs breed. The species is now almost extinct in the previous main habitat (mixed farmland). The remaining population breeds in one forest-fire site on poor soil and on about 20 peat bogs. These habitats have sparse vegetation and low productivity. Observations on the forest-fire site showed that buntings often flew to grain fields to feed both before hatching time and during feeding of nestlings with insects. Telemetry of radio-tagged males showed that they were absent from territories up to one-third of the time and could move up to 3 km to feed in grain fields. Many males congregated in one area with spilled oat grains. All peat bogs used by Ortolan Buntings had grain fields close by, and territories were concentrated on parts of the bogs adjoining fields. Birds were seen flying frequently between bogs and fields. These results suggest that the Ortolan Bunting is a habitat specialist with regard to breeding territories, but is more flexible with regard to feeding areas, and does not have the classical all-purpose territory.

Key words: bunting, Emberzia hortulana, territory, foraging, habitat selection

Percy FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch 7700, Republic of South Africa, e-mail wdean@uctvms.uct.ac.za

Dean, W. R. J. 1998. A framework for the ecology of birds in the Karoo. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 281.

Key elements in the physical environment and vegetation of the Succulent and Nama-Karoo have major consequences for the avifauna. The elements that frame the ecology of birds in the Karoo are: (1) The physical environment: (a) Rainfall unpredictable, low and patchy. (b) Rainfall seasonality and amount, and soils structure, vegetation and habitats for birds. (c) Topographically heterogeneous fertile landscape. (2) Habitat features: (d) Water (rainfall) and soil texture, rather than fertility of soils govern plant production. (e) Vegetation can increase in primary production and cover rapidly in response to rainfall. (f) Patchy distribution of habitats (plant growth forms) within the landscape. Consequences of the physical environment and habitat features for birds: (1) Species richness of birds correlated with rainfall amount. (2) Endemic species are associated with aridity and geological, or geomorphological features. (3) Low production supports persistent (resident) low density consumers. (4) Patchy high production encourages high density nomadic consumers. (5) Brief "windows" of primary production select for short breeding periods and small clutch sizes in nomadic species. (6) Low production encourages group foraging in low density residents (and possibly co-operative breeding) in species with specialised diets.

Key words: arid, soils, habitat-structure, endemic species

1The Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China, e-mail dingcq@panda.ioz.ac.cn; ²Department of Biology, Beijing Normal University, Beijing 100875, China; ³Foping National Nature Reserve, Shaanxi 723400, China.

Ding, C., Liang, W., Zhao, L. & Gong, H.. 1998. The ecology of the Golden Pheasant in the 1996 breeding season. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 282.

The Golden Pheasant Chrysolophus pictus is endemic to China. Although the distribution, macro-habitat use, feeding and habits of the species have been reported, no intensive study has been done on its breeding ecology. A radio-tracking study was conducted from March to August 1996 in Foping National Natural Reserve, Shaanxi Province, China. A total of 12 birds were radio-tracked. The pre-breeding period starts in late March when the winter flocks break down. The adult males move to higher altitude area of territories first. Females wandered over a larger area. Some of the juvenile males joined the adult males while others dispersed far away (up to 5 km). The breeding density in the typical habitat is 12.17 males/km² and the home ranges vary from 6.26 to 71.14 ha. The females have much larger home ranges (average 33.95 ha) than males (average 14.29 ha) although the latter’s were larger in winter. Observations and data from radio-tracking indicated that females wandered about in the males' territories and stayed with some males for several days. We suggest the mating system of the Golden Pheasant is a polygyny of resources defence. The breeding habitat differed from that in the winter area. There were also differences from habitat used in spring (pre-breeding) and in summer (incubation and brood rearing). The birds preferred areas with rich grass and fruits, less tall trees and thick undergrowth. The females usually nested near a hill ridge with a wide field of vision and less bamboo. The clutch size was six to eight eggs and the hatching success was 90%.

Key words: radio-tracking, breeding ecology, mating system, habitat preference

Zoology & Entomology Department, University of Natal, Private Bag X01, Scottsville, 3209, South Africa, e-mail downs@zoology.unp.ac.za

Downs, C.T., Wirminghaus, J.O., Symes, C.T. & Perrin, M.R. 1998. The importance of Podocarpus spp. to the Cape Parrot Poicephalus robustus robustus (Gmelin). In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 282.

Phenological variation at the level of the forest community affects primary consumers who respond by diet switching, seasonal breeding, changes in range use, or migration. Direct evidence of food limitation is scarce in extremely diverse forests in which the food habits of frugivores are poorly known. It has been proposed that bird species composition in forest habitats depends largely on the vegetation structure coupled with food resource availability and abundance which determine which bird species can forage successfully and survive there. Cape Parrots Poicephalus r. robustus occur in afromontane forest patches of eastern South Africa where they feed primarily on endocarps of a variety of forest fruit. Podocarpus falcatus, P. henkelii and P. latifolius are confined to these forests and are particularly favoured as a food source. These trees have a great influence on seasonal feeding forays of P. r. robustus within a local habitat mosaic and are pivotal plant spp. In addition, P. falcatus (a forest canopy emergent), even in its final successional stages, is important for breeding and social interactions of parrots. Predictions relating food resource availability to variation in flock size and forest patch use are discussed together with life history traits of P. r. robustus.

Key words: Cape Parrot, Podocarpus, food availability, flock size, forest

1Department of Avian Ecology, Wroclaw University, Sienkiewicza 21, 50-335 Wroclaw, Poland, e-mail dyrcz@biol.uni.wroc.pl; ²National Institute for Environmental Studies, Onogawa 16-2, Tsukuba 305, Japan

Dyrcz, A. & Nagata, H. 1998. Effect of human activities on breeding ecology of the Eastern Great Reed Warbler. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 283.

The Eastern Great Reed Warbler Acrocephalus arundinaceus orientalis is a fairly common summer visitor to Japan. The species "source" habitat is natural reed beds (2.3 ha) away from residential areas. "Sink" habitats occur as smaller reed beds (0.1-0.8 ha) close to residential areas. We analysed ecological differences between warblers inhabiting "source" and "sink" habitats in two study plots around Lake Kasumigaura, central Japan. The "sink" habitat had a much higher human visitation rate compared to the "source" habitat. Reed quality and insect abundance were similar between the two habitats, although the degree of vegetation heterogeneity was different. Breeding density was higher in the "sink" habitat (23.7 territories/ha) than in the "source" habitat (18.2 territories/ha). Finally, nests at the "source" habitat suffered from significantly higher predation (42.6%) compared with those at the "sink" habitat (12.5%). Although "sink" habitats are generally considered as sub-optimal, the increased human activity may function as a protective umbrella against nest predation.

Key words: Eastern Great Reed Warbler, "source" and "sink" habitats, predation, protective umbrella

Anzengruber str. 23, D-12043 Berlin, Germany, e-mail watzke@metronet.de

Fischer, S. 1998. Corn Buntings Miliaria calandra profit by set-asides in agricultural landscapes. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 283.

The Corn Bunting was formerly a common inhabitant of farmland in Europe. A strong decline of Corn Bunting densities started during the 1970s due to intensification of land-use leading to lower reproduction and higher mortality. After the unification of Germany in 1990 large East-German farms stopped working and thousands of hectares of arable land were turned over to set-aside. Since then the species has increased markedly in the eastern part of Germany. Thus, we hypothesised that Corn Buntings benefit by set-asides. We estimated breeding density and breeding success of Corn Buntings in NE-Germany between 1994 and 1997. Territories were more often in set-asides (47% of 367 territories) than expected by the proportion of set-asides in the study are a (12% of 142 km²). The number of territories within 1-km²-grids was positively correlated with the amount of set-aside but not with other land-use types. The proportion of territories with fledglings was higher in set-asides than in tilled land. The reasons for the preference of set-asides by Corn Buntings and the higher breeding success are: (1) The richness in structure (sparse vegetation for feeding, dense vegetation for nesting). (2) Higher densities and earlier peak abundances of the preferred food of Corn Bunting nestlings (Saltatoria, Araneae, Lepidoptera larvae). (3) The absence of disturbances by agricultural machines.

Key words: Miliaria calandra, habitat, agrolandscape, breeding success

Department of Biology, University of Oulu, POB 333, FIN-90571 Oulu, Finland, e-mail jforsman@paju.oulu.fi

Forsman, J.T., Mönkkönen, M. & Hukkanen M. 1998. Spatial effects of predation in breeding passerine bird community: A landscape view. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 284.

We have showed that heterospecific attraction between breeding forest birds results in aggregated species distribution both between and within communities. Aggregate distribution may be beneficial through increased protection against predation which we confirmed by an experiment made at community level. However, predation or its risk may affect species dispersion at landscape scale too. We investigated how the presence of breeding Sparrowhawk Accipiter nisus affects the spatial configuration and the structure of breeding bird community at the landscape level (30 km²). Birds were recorded at different distances from hawk's nests. We used 1 ha quadrats as sampling units. In total, 13 hawk nests were found and almost 300 quadrats were surveyed. We assumed that predation risk increases with decreasing distance to Sparrowhawk nest. If heterospecific attraction is beneficial through increased protection against predation species distribution should be more clumped near hawk nests than farther away. Results suggest that the number and the abundance of species decreases with decreasing distance to hawk nests. Predation or its risk seem to be an important factor affecting structure and spatial patterns of forest bird communities at the landscape level.

Key words: heterospecific attraction, predation risk, breeding bird community, landscape pattern, Finland

BRD, USGS/NHB-378, National Museum of Natural History,10th & Constitution, NW Washington, DC 20560-0111, USA, e-mail Foster.Mercedes@nmnh.si.edu

Foster, M.S. 1998. Ecology and behaviour of the Alder Flycatcher Empidonax alnorum, Tyrannidae in winter. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 284.

The Alder Flycatcher Empidonax alnorum (Tyrannidae) winters from Colombia and Venezuela, south to northern Argentina. We studied the species in Manu National Park, Madre de Dios, Peru. In this area the species occupies riparian zones along lowland meander rivers as well as adjacent transition zone forest in the floodplain. These habitats have a number of age-related longitudinal zones (parallel to the river margin) that are short term (1-2 year) transitory stages in the succession to floodplain forest. The fast growing plant species that make up these habitats are suitable for commercial harvest for paper pulp. We examined habitat use of the species in an attempt to identify the effects of such harvest and resulting habitat loss on these birds. The Alder Flycatcher favours two longitudinal zones where it establishes territories. The territories may be long-term or transitory, and are often occupied and defended by two individuals, generally of different age. One bird tends to be more active in territory defence than the other. Defence involves patrolling, vocal duels, and chases. Birds sally for insects but also eat large quantities of fruit.

Key words: Tyrannidae, migrant, Peru, habitat, forest

 

South China Institute of Endangered Animals, 105 Xingang Road West, Guangzhou 510260, China, e-mail gzgyrbir@publici.guangzhou.gd.cn

Gao, Y. 1998. The ecology of the Hainan Hill Partridge Arborophila ardens on Hainan Island. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 285.

The Hainan Hill Partridge (HHP) is an endemic, endangered bird in China. This study was conducted during 1988-1994 mainly in Ba Wang Ling Reserve. We created the method of observing at fixed spots using baits which increased the siting of rarely seen individuals. HHP only live in primitive tropical ravine rain forest, mountain rain forest and some good forest remaining after logging from 600-1200m above sea level. They feed on plant seeds and insects such as termites under the litters on the ground. There are two daily activity peaks, in the morning and afternoon. In more than 400 observations, HHP occurs strongly year around, except during breeding, when they live in family group. We saw the eating peaks in the annual cycle of HHP at the fixed spots. We recorded daily times and amount of the singing and their distribution in a year on basis of once every two weeks. We also documented their living habits, home range, display and copulation behaviour during breeding season, their nesting site and nest structure, chick growth and mature period of sex, etc. The population density in the core of the Reserve was 7km² in 1992. Using an optimistic estimate over the total 650 km² forests, the total number of HHP on Hainan Island would be about 4550. We determined the moult time and moult peaks of different body parts and as a whole in captivity. In 1991 we bred two clutches successfully in captivity.

Key words: Hainan Hill Partridge, ecology, situation, endangered

N.K. Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Vavilov street 26, 117808 Moscow, Russia, e-mail gavrilov@tgolubeva.home.bio.msu.ru

Gavrilov, V.V. 1998. Ecology of reproduction in some northern shorebirds and passerine birds. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 285.

The main specific goals of this research are: (1) To study biology of reproduction in 18 species of shorebirds and in 10 species of passerine birds in natural northern environments. (2) To find the general or local adaptations in birds’ ecology and behaviour to the reproduction in northern environments. (3) To find the factors limiting reproduction and time reserves. (4) To investigate the influence of species social organisation on their different ecological characteristics. In seven expeditions to northern Russian tundra the main method was to study time budgets of breeding birds. Shorebirds have four types of territorial distribution. Territory area in all species depends on the food availability and bird body mass and areas in shorebirds are relatively bigger than in passerines. The type of the territorial distribution determines the energetic costs of reproductive behaviour in males of all studied species. Time spent for the maintenance and reproductive behaviour in all birds is fixed in daily rhythms. These data address the problems of annual patterns of energy expenditure, parental investment in mating systems and systems of parental care, bird adaptation to reproduction in northern environments, and the evolution of birds’ adaptive strategies.

Key words: Russia, breeding, sociality, time-budget

Edward Grey Institute, Dept. of Zoology, South Parks Rd., Oxford OX1 3PS, UK, e-mail Andrew.Gosler@zoology.oxford.ac.uk

Gosler, A.G. 1998. Inheritance of individual quality: Winter fat storage in the Great Tit. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 285.

At temperate latitudes, small passerines such as the Great Tit Parus major carry greater fat reserves as insurance against starvation in winter. Observation, over many years, of fat in a ringed Great Tit population found that fat levels are time and temperature dependent with fat deposited each day for use overnight and with more fat carried on colder days. However, the costs of transporting fat reduce the optimal fat level below the maximum possible. The optimum, resulting from the trade-off between starvation and predation risks, differs among individuals which differ in their access to food, starvation risk and predator exposure. Thus, juveniles often carry more fat than adults; survival analysis suggests this reflects their greater starvation risk. Fat reserves show zero heritability, as expected for a condition indicator with strong environmental determination. Here I report, however, a highly significant negative correlation (r₂₉ = -0.497, P = 0.004) between brood-mean winter fat and mid-parent mean winter fat. Since parent and offspring fat reserve optima differ in winter, this provides strong evidence for the inheritance of individual quality (though not necessarily transmitted genetically) with the fitter offspring of leaner parents having greater fat reserves than the leaner, less fit offspring of fatter parents.

Key words: heritability, survival, starvation risk, Parus major

USDA Forest Service, Southern Hardwoods Laboratory, Stoneville, MS 38776, USA, e-mail donlk@tecinfo.com

Hamel, P.B. 1998. Landscape and Habitat Distribution of the Cerulean Warbler Dendroica cerulea in extensively fragmented Mississippi alluvial valley, USA. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 286.

The population of Cerulean Warbler Dendroica cerulea, Parulinae has declined substantially (50% by North American Breeding Bird Survey 1966-1995). Among the most abundant breeding species in Mississippi Valley forests 100 years ago, this temperate-tropical migrant occurs today in interiors of only a few large forest tracts. Conservation of the species requires knowledge of extent, type, and successional stage of forest used, reproductive success in that forest, and silvicultural activities required to produce habitat. The present investigation (1992-1998) involves a nested set of procedures including landscape analysis of regional surveys (7x10⁶ ha), spatial analyses of distribution within tracts (5-8000 ha tracts), and analyses of tree species selection and 3-dimensional vegetation structure within territories at local scale (50 ha plots) designed to document habitat use and determine reproductive success. Of 66 nests found, nine were parasitised by Brown-headed Cowbirds Molothrus ater (Icterinae) and 21 produced 37 host fledglings. Sexes overlap in habitat use; males occupy higher portions of the canopy. Distribution at tract scale is apparently random, but results are equivocal. At regional scale Cerulean Warblers clearly are restricted to large tracts and dissociated from agricultural areas closer than 5-8 km.

Key words: habitat utilisation, landscape ecology, forest interior, reproductive success, neotropical migrant

Department of Biology, California State University, Fullerton, CA 92834, USA, e-mail mhorn@fullerton.edu

Horn, M. H., Loeffler, W. E., Dahdul, W. & Pham, N. H. 1998. Foraging ecology and response to shifting prey abundance of terns and skimmers in Southern California. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 287.

We compared the food habits and foraging locations of Caspian Sterna caspia, Elegant Sterna elegans, and Forster's Sterna forsteri Terns and Black Skimmer Rynchops niger that have recently colonised the Bolsa Chica Ecological Reserve in coastal southern California to estimate (1) the likelihood of their continued coexistence and (2) their shifts in diet as two major prey items, Northern Anchovy and Pacific Sardine, have changed in abundance over the last decade, probably as a result of warming ocean temperatures. Based on direct observations of prey transfers and fish dropped by the birds at the nests, we found that mean dietary overlap (Morisita-Horn, C) was relatively low (53%) across all species pairs as a result of a combination of differences in prey type, prey size, and foraging habitat. These results suggest that food resource partitioning may be sufficient to allow coexistence of the four species at Bolsa Chica. Analysis of food habit data for a recent five-year period (1992 to 1996) reveals dietary shifts especially in Elegant Tern, the most abundant species at the site, that parallel the rise of Pacific Sardine and fall of Northern Anchovy in the Southern California Bight.

Key words: foraging prey abundance, terns, skimmer, fish

Department of Vertebrate Zoology and General Ecology, Moscow State University, 119899, Russia, e-mail Valery@VGavrilov.home.bio.msu.ru

Ivankina, E.V., Kerimov, A.B., Ilyina, T.A. & Gavrilov, V.M. 1998. Ecological effect of flocking and group settlements with special reference to Great Tit Parus major. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 288.

Field observations were carried out in an optimal habitat where the males occupied individual breeding territories within their winter flock range. Social status in the wintering flock was strongly related to the location of a male's breeding territory within the flock range: Dominant males occupied territories near the centre of the flock range. Effective competitive interaction is possible only after the loss of territoriality and the formation of flocks. This explained translocation of flock social asymmetry into breeding settlement asymmetry and according to individual morphological and physiological parameters. The effects of morphological and physiological quality on the competition is most striking under the unfavourable conditions of the critical period. Flock size reduction during the critical period may reflect increased competition between males of similar quality for limited reproductive resources in the optimal habitat. Formation of a hierarchical structure not only ensures the stabilisation of the existing level of organisation but also the rapid fixing, over many generations, of a new evolutionary beneficial feature in all of the members of the flock.

Key words: sociality, territoriality, dominance, status

Laboratory of Wildlife Ecology, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro 080, Japan, e-mail iwami@obihiro.ac.jp

Iwami, Y. 1998. Nesting density and nesting success of Black Kites Milvus migrans in suburban and agricultural areas. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 288.

The nests of Black Kite Milvus migrans are usually regularly spaced, but they may nest at very short distances from one another when food is abundant. I compared the nesting performance between two habitats which differ in nest density. The nesting density, breeding success, nestling growth and home range size were investigated in eastern Hokkaido (42°N, 143°E), Japan, from 1994 to 1997. The population of Black Kites nesting in a study area (748 km²) increased from 51 pairs in 1994 to 81 pairs in 1997. The number of breeding pairs have increased in the suburban area (around the Obihiro city), but in agricultural area the number has not changed. The nesting density in suburban area was higher than in the agricultural area. There was no difference in the number of fledglings between the suburban area and the agricultural area. However, the maximum body weights of nestlings in the suburban area were heavier than in the agricultural area. The home range size was larger in the agricultural area than in the suburban area. In the suburban area, there are some dumps and poultry runs where Black Kites could get food easily. Therefore it seems that many breeding nests were concentrated around a dump and home range size was smaller. In the agricultural area without fixed foraging sites, breeding pairs get food by enlarged home ranges

Key words: Black Kite, nesting density, nesting success, suburban area, agricultural area

Subdireccion de Investigaciones en Aves Marinas del Instituto del Mar del Peru IMARPE, Apartado 22, Callao, Lima, Peru, e-mail jjahnck@mail.cosapidata.com.pe

Jahncke, J. & Goya, E. 1998. Latitudunal and seasonal variation in the diet of Guanay Cormorants and Peruvian Boobies along the Peruvian coast. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 281.

The diets of Guanay Cormorants Leucocarbo bougainvillii and Peruvian Boobies Sula variegata were studied by examining 4425 pellets and 1220 regurgitations respectively. Five different guano areas were surveyed to determine variation. Peruvian Anchovy Engraulis ringens was the main prey, comprising 42,30% of the diet Guanay Cormorant and 76,23% of the diet of Peruvian Boobies. Highly significant differences on anchovy consumption were found in among surveyed areas and among months when samples were obtained. Latitudinal differences in diet related known Peruvian anchovy distribution patterns: high availability in the northern-central coast of Peru, scarcity around San Juan and low availability in the south. The diet of the Guanay Cormorant did not show seasonal patterns. Consumption of anchovies by Peruvian Boobies shows higher availability of this prey during summer as compared to winter. These diet variations indicate that food supply in the Peruvian Upwelling System is very variable and that anchovy availability has large geographical and seasonal fluctuations.

Key words: Guanay Cormorants, Peruvian Boobies, diet, feeding ecology, Peruvian anchovy

1 Department of Biological Sciences, University of Arkansas, Fayetteville, AR72701, USA, e-mail djames@comp.uark.edu; ² Southeast Missouri State University, Cape Girardeau, USA

James, D.A. & White, E.M. 1998. Avian community structure in overgrown fields in northern USA. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 289.

Bird communities in early successional and hay fields were investigated in the state of Michigan (USA) by identifying avian microhabitats. Vegetation structure in bird centred plots was measured and subjected to multivariate analysis. Random plots represented overall vegetation structure. For the 11 common birds, the first principal component (PC1) represented vertical foliage density (shrubs and trees); one species in the most open environment, another in the densest stands, the others scattered in between. PC2 described ground cover from bare ground to dense grassland. Correlating PC1 factor patterns for each species with random samples indicated there were three avian specialists (low correlation), five generalists (high rho), three intermediate. Duncan's multiple range procedure showed eight species shared the same habitats in the vegetation mosaic while three species occupied three distinctly different habitats. Classifying random samples with respect to the bird species using multiple discriminant analysis showed an increase in number of species in complex (dense) habitats in Michigan, but not as strikingly so as in similar studies in Arkansas (USA) and Africa. The present study highlights avian community organisation in successional stage fields.

Key words: community, microhabitat, diversity, specialisation, species-packing

Institute of Biology, LV-2169 Salaspils, Latvia, e-mail ring@acad.latnet.lv

Janaus, M. 1998. Sixty year population dynamics of the White Stork Ciconia ciconia in Latvia. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 289.

White Stork numbers have decreased strongly over a big part of breeding range in Europe, although the dynamics in Latvia are different. Data were obtained during five international censuses of White Stork using questionnaires. In 1934 there were 6750 inhabited nests or 13 pairs/100 km² of territory, in 1958 there were 6300 inhabited nests or 10 pairs/100 km², in 1974 there were 5800 inhabited nests or 9 pairs/100 km², in 1984 there were 6300 inhabited nests or 10 pairs/100 km², in 1994 to 1995 there were 10600 inhabited nests or 17 pairs/100 km², respectively. The mean number of chicks per inhabited nest decreased from 2.7 chicks in 1934 to 2.1 chicks in 1995. The number of nests built with human assistance (artificial nest basement) decreased from 87% in 1934 to 29% in 1995. The number of nests built on trees decreased from 91% in 1934 to 30% in 1995, nests on poles increased from 0 to1% in 1934 to 1974 to 43% in 1995. The number of nests built on buildings increased from 9% in 1934 to 27% in 1995. One of the reasons for the increase of the White Stork breeding population in Latvia between 1984 and 1995 could be the strong decrease of chemicals used in agriculture.

Key words: White Stork, population dynamics, pesticides, Europe

4225 Reghin Str, Eminescu 26, Romania

Kalabér, L.V. 1998. The status of the Capercaillie Tetrao urogallus, Hazel Grouse Tetrastes bonasia and Black Grouse Lyrurus tetrix in Romania. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 291.

In the last 30 years I noticed an essential change in these populations. Causes for diminution include these species being connected to the biogeocoenosis of the soil, the organochlorines used in agro-silviculture, the cutting of forest, intensive sheep breeding in some regions of the country and grazing in alpine zones. The lack of laws concerning this field as well as the attitude of the people such as inappropriate legal hunting, illegal hunting and traps, must also be taken into consideration. I hope my work, as well as that of the International Conference on Galliformes, which took place in my home city of Reghin between 25 to 27 October 1995, highlight the eco-ethological problems of the species in this avifauna. In the recent publication, "The Atlas of the Breeding Birds in Romania" (1994 Romanian Ornithological Society), the status of the populations is presented as follows: Tetrao urogallus 10000 individuals, Tetrastes bonasia 9000 to 12000 individuals, Lyrurus tetrix 90 to 100 individuals or less. In the present work I give an ecological, autecological and ethological description of each species. I try also to give a detailed description of the recommendations which have to be adopted in order to maintain and save these populations in Romania and their entire range due to the zoogeographical repartition.

Key words: autecology, eco-ethological problem, causes for diminution

Wildlife Management Laboratory, Forestry & Forest Products Research Institute, PO Box 16, Tsukuba-Norin, Ibaraki 305, Japan, kawajin@ffpri.affrc.go.jp

Kawaji, N. 1998. Habitat preference by the Asian Stubtail Urosphena squameiceps in northern Japan. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 291.

The Asian Stubtail is a ground nesting bird usually breeding within the relatively dense bamboo grass cover in deciduous forests in northern Japan. Habitat use by the stubtail has not been well documented. We found a number of advantages for the species breeding within this habitat. The nesting success of this stubtail was higher rather than that of the Great Tit for six breeding seasons (p < 0.20) with the stubtail preferring bamboo grass habitat with ample canopy cover. The food of nestlings was dominated by caterpillars (83.1% by dry weight). Many of these caterpillars fell from the canopy in order to pupate or escaped from predation of canopy birds The opening of the bamboo grass root utilised as nesting sites, are roofed by the deciduous leaves that shed in autumn.

Key words: Asian Stubtail, habitat preference, nesting success, bamboo grass cover, northern Japan

Department of Biology, Queen's University, Kingston, Ontario, K7L 3N6, Canada, e-mail camerond@biology.queensu.ca

Keast, A. 1998. Fire responses: Australian forest birds. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 291.

Australian eucalypt forests, rich in volatile oils, highly fire-prone, burn every 3-13 years. Are birds, like plants, "fire adapted"? Following the devastating January 1994 fires in eastern N.S.W., with complete loss of undergrowth and tall shrub layers, trunks blackened, ground bare, and tree foliage dead: (1) Foliage-gleaners, nectarivores, and most thicket dwellers were absent. (2) In places up to six parrot species arrived to feed on fire-opened seeds in treetops. (3) Varying with quality of habitat some generalists, trunk-feeders, ground-pouncers, a flycatcher, and predators remained on territories. They ate post-fire emergent ground beetles and ants, chironomids and odonates from the stream, using expanded ranges of feeding substrates and behaviours. Edge areas were important in survival but adjacent unburnt rainforest were not used as refuges. After 6 months, with accelerated plant regeneration some small foliage gleaner returned and bred. Three years later balanced assemblages were largely restored. The inbuilt habit of adjusting to dry seasons by local movements may partly preadapt Australian birds to fire effects. Fire responses differ with habitat, season, fire intensity (see Woinarski, J.C.Z. & H.F. Recher 1997. Pacific Conservation Biology 3: 1-28).

Key words: adaptation, feeding, seasonal movements, fire

Research Institute and Museum of Zoology, Research Group "Biology and Phylogeny of Tropical Birds", Adenauerallee 160, D-53113 Bonn, Germany, e-mail kl.schuchmann.zfmk@uni-bonn.de

Khoury, F. & van den Elzen, R. 1998. Feeding and breeding ecology of a rare endemic, Tristram's Serin, Serinus syriacus , in Jordan. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 292.

The breeding population of Tristram's Serin in Wadi Dana, Jordan, was discovered only in 1995. Between October 1995 and June 1997 data on diet and habitat preferences were collected. During the winter months (October to March) serins fed almost exclusively on Artemisia sieberi seeds (88% of observations); during the breeding season (April to July) buds and seeds of more than 70 plant-species were taken. Breeding areas were situated in rocky open woodlands at 900 to 1200 m above sea level. Numbers of breeding pairs increased with canopy density. Juniperus phoenicea and Quercus calliprinos were preferred for nest building. At the beginning of the breeding season, serins fed their young from fallows in the near vicinity, later on distances of 200 to 1000 m had to be covered between nest and feeding grounds. This might be a limiting factor, as second broods were observed rarely. Access to permanent water may be another key factor determining habitat quality. During the winter months Tristram's Serins fed also in open habitats (e.g. Artemisia -steppes), but returned each evening to the wooded breeding-sites, using the largest trees for communal roosting.

Key words: ecology, Serinus syriacus, feeding habitat, breeding habitat, Jordan

1Institute for Forest Ecology, SAS, Sturova 2, 96065 Zvolen, Slovakia, e-mail kristin@sav.savzv.sk; ²Department of. Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK; ³Konrad Lorenz Institute for Comparative Ethology, Savoyenstr. 1a, A-1160 Vienna, Austria

Kristin, A., Vanhinsbergh, D., Valera, F. & Hoi, H. 1998. A comparison of the habitat use and diet composition of two related shrike species Lanius collurio and Lanius minor: Implications for conservation. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 293.

Although Red-backed and Lesser Grey Shrikes coexist, their home ranges rarely overlap. This is thought to be a consequence of interspecific competition. However, little is known about the ecological factors which determine the relative distribution of these two species. Over the last 20 years populations of both species have declined in many parts of their European range. This decline has been attributed to agricultural intensification and in particular the removal of suitable breeding habitat and a reduction in invertebrate abundance due to the widespread use of pesticides. It is important to examine the interaction between the two species on an ecological and behavioural basis in order to establish the factors determining the degree of interspecific competition. In this study we used a comparative approach to try and identify the important habitat features and prey characteristics for both shrike species. The results suggest that where the two species coexist the Lesser Grey Shrike is dominant. However, the Red-backed Shrike seems to be more flexible in its choice of breeding habitat. In addition, Red-backed Shrikes are less dependent on large prey items than Lesser Grey Shrikes, making them less vulnerable to fluctuations in prey abundance. Although the Lesser Grey Shrike is the more dominant of the two species, the high flexibility of the red-backed shrike makes it less constrained in coping with habitat changes. These results may explain the increased susceptibility of the Lesser Grey Shrike to environmental change. Hence, this study could provide a good basis for making practical conservation decisions.

Key words: Lanius minor, Lanius collurio, habitat preference, prey selection, behaviour

Department of Forest Protection and Wildlife Management, Faculty of Forestry, Technical University, Masarykova 20, SK - 960 53 Zvolen, Slovakia, e-mail zilinec@sav.savzv.sk

Kropil, R. 1998. Breeding bird communities of primeval and natural forests in the west Carpathians (Central Europe). In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 294.

The last remnants of primeval and natural forests in the West Carpathians, conserved until the present time, represent a unique opportunity to study their associated bird communities or ecological principles in general. I analysed the structure of breeding bird communities in different Central European natural and primeval forest reserves over an altitudinal range from the lowland floodplain forest, through oak, beech, fir-beech, fir-spruce-beech, spruce to the dwarfed-pine forests (altogether 15 plots). Bird censuses were carried out from 1990 to 1997 using the combined mapping technique. Different aspects of community structure such as species richness, overall density and diversity as well as guild organisation are discussed in detail. Foraging guilds were of particular interest. The overall density of birds declines with increasing altitude. The highest values of species richness and diversity were found in both the lowland and mixed mountain primeval forests. More than 80% of birds fed on invertebrates and almost half of them were foliage insectivores. A relative high proportion of hole and ground nesters is a characteristic of primeval and natural forests under study.

Key words: bird communities, primeval forests, natural forests, ecology, Central Europe.

 

The Research Centre of Wild Bird Society of Japan, 3-1-6 Kojima-cho, Chofu-city, Tokyo 182-0026, Japan, e-mail QZD02221@niftyserve.or.jp

Kurosawa, R. 1998. Effects of forest fragmentation on bird abundance in Japanese forests. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 295.

Decline of forest birds is an urgent issue in many areas of the world today. Fragmentation as well as loss of forest is one of the most important factors for the decline of forest species in North America. However, the mechanism of the bird decline is not understood in Japan. I studied the abundance of forest birds by point census in broad-leaved deciduous forests in temperate zone of Hokkaido, Japan between May 1996 and June 1997. The number of the species recorded per 50 m radius plot was positively related to the forest area. Forest interior species were represented by Picidae woodpeckers, Turdinae thrushes, Sylviinae warblers, Muscicapinae flycatchers, and Paridae tits. Typical edge species were Emberizidae finches and Corvidae crows. The negative edge effect observed in North America, such as increased nest predation and brood parasitism, were also noted in the Japanese forests not only at the very edge but farther into the forest. Three of the brood parasitic cuculids occurred from the edge to 200 m into the forests. Jungle crows, the most important potential nest predator, were abundant at the edge and present for at least 300m into the forest. In order to have a refuge from these edge effects, a forest fragment must have at least 300 m radius reflecting a minimum area of about 30 ha.

Key words: conservation, edge effects, nest predation, brood parasitism

Smithsonian Tropical Research Institute, Apartado 2072, Balboa, Panamá, e mail poulin@tour-du-valat.com 

Lefebvre, G., Poulin, B., Jaramillo, C., Ibáñez, R. & Rand, A.S. 1998. Avian predation on lizards and frogs in a Neotropical humid forest. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 295.

Although small lizards and frogs are a likely food resource to many tropical landbirds, this predator-prey system is poorly known. A one-year investigation of avian diet based on regurgitated samples shows that 50% of the common, primarily insectivorous species regularly prey upon lizards and/or frogs. These birds (22 species, 9 families) fed on invertebrates averaging 3 to 17 mm in length, weighed from 11 to 195 g, and had a bill 12 to 50 mm long. A logistic regression analysis revealed that intensity of foraging at army-ant swarms best explains the likelihood of a bird species preying on lizards, leading to a classification 91% correct. In contrast, bill and body lengths classify 88% of the frog-eating birds, which had a strict 1:7 bill/body length ratio (in contrast to a mean but variable 1:10 in other species). Some 97% of all vertebrate prey (n = 105) were from Anolis and Eleutherodactylus. Birds preyed opportunistically upon the different Anolis species, but almost exclusively on the smaller juveniles. Birds preyed upon the Eleutherodactylus species proportionally to their abundance, but avoided feeding on Colosthetus and Bufo, the most common anurans at our study site.

Key words: diet, foraging, morphology, predator-prey adaptations, herpetofauna

1Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China; ²Changbai Shan Natural Reserve, Jilin 133613, China; ³Lushuihe Forestry Bureau, Jilin 134506, China

Liu, X., Li, S., Sun, Y., Wang, L., Piao, Z., Zhang, X., Wang, T. & Wu, Z. 1998. The structure of breeding bird communities in the secondary forest at Changbai Mountain, China. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 296.

Our work was conducted in 1994 and 1995 at the Changbai Mountain in northeast China. A total of 36 bird species were recorded in three plots in the secondary forest, with the sizes of 10.5 ha, 16.0 ha and 27.0 ha respectively. Species number and breeding pairs in each plot were: 23 species, 40.5 pairs; 23 species, 46.0 pairs; 27 species, 73.5 pairs respectively. The number of breeding pairs generally increased with the plot size. The composition of breeding bird communities in the secondary forest showed a trend of increasing complexity with forest vegetation succession, from clear cutting slash to climax community. There was a significant relationship between bird species diversity and vegetation stratum diversity (r = 0.85, p < 0.05). Species-number coefficient of edge species generally increased with the length of forest edge. The density of breeding bird within 50 m from forest edge was highest, being an average of 51 pairs per 10 ha in two plots. Forest birds occupied 58% of total species in the secondary forest (20 years of age) plot, with the density of cavity-nesting and canopy-nesting birds much lower than that in primary mixed conifer-deciduous forest plot. However, the density of bush and ground-nesting birds in the secondary forest was higher.

Key words: bird communities, secondary forest, edge effects, ecology

 

Department of Ecology, Lund University. SE-223 62 Lund, Sweden, e-mail jon.loman@zooekol.lu.se

Loman, J. & von Schantz, T. 1998. What bird species breed in small habitat islands? In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 296.

Birds were censused by territory mapping in habitat islands during one or two breeding seasons. The islands were situated in extreme agricultural areas in southern Sweden. There were 140 islands that ranged in area from 24 ha down to 0.01 ha. The species' differed in their acceptance of the smallest ones. Was this related to the size of the bird, migratory habits or habitat preferences?

Key words: landscape ecology, agriculture, habitat, fragmentation

Laboratory of Wildlife Ecology, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro 080, Japan, e-mail makoto@obihiro.ac.jp

Kinoshita, M. 1998. Relationships between habitat quality and territory density or breeding performance in Common Stonechats Saxicola torquata. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 296.

For Common Stonechats Saxicola torquata which use perches for foraging, the distribution of perches restricts the place of activities. Therefore, the distribution of available foraging sites seems to affect territory densities. I investigated relationships between habitat quality (= foraging site size and amounts of food) and territory density or breeding performance among three habitats (A, B and C) in Hokkaido Japan from 1995 to 1997. To compare the difference of habitat quality, available foraging site size and available amounts of food in a circle with a radius of 50 m from nests were investigated in early breeding seasons. Territory size, the distance between nests, male arrival dates and breeding performance were also investigated. Habitat B had largest foraging sites and a large amount of food in all years. Territory size and the distance between nests were smaller and shorter respectively in B than in C in all years. Male arrival dates were earlier in B than in other habitats only in 1997. Breeding success rates (the percentage of total fledglings per total eggs in a habitat) was higher in A than in B in 1995 and in C than in B in 1996 and 1997. The main cause of breeding failure was predation. Habitat quality seemed to affect territory density, but Common Stonechats did not always prefer high quality habitats. Predation may affect habitat selection in Common Stonechats.

Key words: breeding performance, perch hunting, Saxicola torquata, Common Stonechats, predation

Ecology, Evolution, and Conservation Biology Program, University of Hawaii, Honolulu, HI, USA and P.O. Box 177, Rainbow Beach, QLD, 4581 Australia, e-mail zltmale@mailbox.uq.edu.au

Male, T,D. 1998. Defense of fruiting trees by Wompoo Fruit-Doves Ptilinopus magnificus. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 297.

Tropical forests typically contain frugivorous birds which overlap extensively in diet, yet resource defense is rarely reported. Wompoo Fruit-Doves Ptilinopus magnificus are one of the largest frugivores in Australian rainforest. Their range overlaps with that of the Green Catbird Ailuroedus crassirostris and both rely on many of the same fruit species. I studied foraging activities of these two species by quantifying fruit species used, duration of foraging visits, and cause of visit termination. During winter 1997, Wompoo Fruit-Doves and Green Catbirds spent much of their time foraging in three species of tree which were in fruit: Beilschmiedia obtusifolia, Acmena hemilampra, and Halfordia kendack. 66.7% (n = 12), 80.0% (n = 20), and 14.3% (n = 28) of Green Catbird visits to these trees, respectively, ended because they were displaced and chased from by Wompoo Fruit-Doves. Displacement drastically reduced visit duration compared to the visit duration of undisturbed Green Catbirds. Average visit length of undisturbed versus displaced Green Catbirds for these three tree species, respectively, were: 77.2 min and 2.4 min, 5.8 min and 1.7 min, and 36.7 min and 5.8 min. Resource defense of this sort has rarely been reported in frugivorous systems. In this case, Wompoo Fruit-Doves had a substantial impact on the foraging activities of Green Catbirds, effectively preventing them from foraging in some heavily fruiting trees.

Key words: frugivory, Australia, competition, Green Catbird, Ailuroedus crassirostris

Department of Ornithology, National Museums of Kenya, PO Box 40658, Nairobi, Kenya, e-mail kbirds@users.africaonline.co.ke

Matiku, P.M. & Bennun, L.A. 1998. Habitat choice by the globally threatened East Coast Akalat Sheppardia gunningi sokokensis (Van Someren 1921) in Arabuko-Sokoke Forest-Kenya. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr. Durban, University of Natal. Ostrich 69: 297.

This study was carried out on the globally threatened East Coast Akalat in Arabuko-Sokoke Forest to determine the proximate factors that influence its spatial distribution. Playback was used to stimulate the bird to reveal its presence. Fifteen habitat factors predicted to be important Akalat habitat choice cues were recorded in territory and non-territory sites and compared. Logistic regression models were used to select the best habitat predictors of the Akalat's presence and density. The best Akalat macro-habitat selection predictors were high percent canopy density, high number of stems greater than 6 cm dbh and low numbers of cut stems whereas its most important micro-habitat selection cues were high percent litter cover, high percent canopy density and high percent vegetation cover at 2 m high. Sites without Akalat had higher numbers of cut stems. The greatest amount of food was associated with the presence of Akalat. Results suggested that: (1) East Coast Akalat had the ability to select macro and microhabitats suitable for its survival. (2) Humans affected Akalats' habitat choice by affecting vegetation structure suitable for the species. (3) Percent canopy density, mossy logs and percent vegetation cover at 2 m high could be used as quick rapid indices in predicting habitat quality for the Akalat.

Key words: Akalat, , factors, logistic, habitat selection

Institute of Ecology and Evolution, Leninsky pr. 33, 117071 Moscow, Russia

Matyukhin, A.V. & Krechetov, Yu. N. 1998. Correlation between economic crisis and reproductive success of introduced population of Common Mynas Acridotheres tristis in Russia. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 298.

In this century in Middle Asia a large range expansion of Common Myna Acridotheres tristis was recorded. From 1960 to 1970 aviculturists released many birds, which survived the winter season in the Moscow region. The first birds in Moscow were recorded in 1965 in town-park Kuzminki, from 1966 to 1974 at a pig-farm Goliyanovo and in the Solntsevo region from 1970 to 1971. First breeding in Moscow was recorded in the grounds of the Veterinary Academy in 1969. In 1983 at Rasskazovka cow-farm we recorded a population of Common Mynas containing 60 to 80 birds. In the winter season birds inhabited the farm, in summer they were distributed through neighbouring villages. During 1984 to 1992 the population was stable and contained 50 to 60 birds. Because of the recent economic crisis and reduction of livestock, the population of Common Mynas has decreased and now contains only 5 to 8 birds.

Key words: Acridotheres tristis, breeding biology, range expansion

1Ohio University, Athens, Ohio 45701, USA, e-mail cc224388@oak.cats.ohiou.edu; ²Arizona State University, Tempe, AZ, USA

Miles, D.B., Corbin, C,E. & D.L. Pearson. 1998. The ecological morphology of community structure and foraging regime in three old world lowland forest passerine assemblages. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 298.

We used an ecomorphological approach to investigate the relative importance of phylogeny and ecology in the organisation of tropical lowland rainforest bird communities. We also used multivariate statistical techniques to investigate correlations between morphology and foraging regime. We measured eight external morphological characters and five foraging variables from passerine species from Borneo, New Guinea and Gabon, respectively. We characterised the patterns for covariation among the morphological traits using principal components analysis. We also applied canonical variates analysis to determine: (1) the degree of separation among the avian assemblages in the morphological volume and, (2) analyse concordant patterns between morphology and foraging behaviour. Foraging technique, substrate, height, and plant type were used in canonical variates analysis with the morphological attributes. New Guinea and Borneo showed a high degree of similarity in the structure of the morphological volume, despite relatively low overlap in taxonomic similarity (24% overlap among families). Most of the variation in New Guinea and Borneo was explained by body size (88% and 72%, respectively). PC2 described a contrast between tail and tarsus length. Whereas size explained most of the variation in PC1 for the Gabon site, the remaining axes described a different set of morphological contrasts. For example, PC2 had high loadings for bill and leg characters and PC3 was mainly associated with tail length and culmen width. The canonical analysis showed little overlap between Gabon and New Guinea or Borneo. The sites were separated principally by body size for Canonical Axis 1. Canonical Axis 2 separated the sites based on leg and bill characters. Our results suggest a strong role for phylogeny in affecting the ecomorphological patterns among sites with ecology having a role in structuring local assemblages.

Key words: ecomorphology, foraging behaviour, community structure, passerines, biodiversity

Department of Ornithology, National Museums of Kenya, P.O. Box 40658, Nairobi, Kenya, e-mail kbirds@users.africaonline.co.ke

Muchai, M., Bennun, L. & Lens, L. 1998. The ecology of Sharpe's Longclaw Macronyx sharpei - a Kenya grassland endemic bird. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 299.

Sharpe's Longclaw is a Kenyan montane grassland endemic, and a range-restricted, vulnerable species. Its populations are thought to be in decline, but its ecology and habitat requirements have been little studied. Between November 1995 and May 1996, we mapped 41 longclaw territories in a 3 km² study area on the Kinangop Plateau, censused numbers, assessed home range and foraging behaviour, and related our findings to vegetation measures. Twenty four birds in nine territories were followed to give precise estimates of home-range size and to monitor behaviour and microhabitat preference. With an overall density of 0.4 birds/ha, Sharpe's Longclaws lived in pairs or consistent groups of up to seven individuals. They were sedentary and territorial, with a mean home range size of 0.5 ha. The species avoided non-grassland areas entirely. Within grassland, it showed a strong preference for short grass with tussocks. Territory sizes and foraging ranges were smaller, and rates of pecking for food higher, in this grassland type than in open short grass or long grass. Land use changes, in particular conversion to cultivation or woodlots and ploughing up of grassland to remove tussock species, pose a serious and immediate threat to this species.

Key words: habitat requirements; tussocks; Kinangop Plateau, land use

Research Centre, Wild Bird Society of Japan, 2-35-2 Minamidaira, Hino, Tokoyo 191, Japan, e-mail PXP10344@niftyserve.or.jp

Narusue, M., Kanai, Y., Fukui, K., & Kato, N. 1998. Project Comorant: moving a breeding colony of Great Comorants in central Tokyo, Japan. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 300.

Recently numbers of Great Comorants Phalacrocorax carbo have recently increased in Japan, though they had decreased during the 1970s. They started to inhabit the Hamarikyu Garden, Tokyo in 1983. In 1993, 746 nests were counted in spring, and 7 296 birds in July. The trees the comorants used were covered with their faeces, and started to wither. We co-operated with Tokyo Government in restoring the historical garden. In 1994 we made a plan to move the colony site instead of controlling the number of comorants. In February, 1995, we set up 15 decoys of comorants on a small uninhabited island about 2 km from the garden and ten decoys of great egrets were set in August. We cleared the bushes on the island because comorants prefer groves of trees with little undergrowth to roost and nest. In 1996, we removed nests from the garden, except in a protected area, followed in December 1996 by placement of bird repellent strings. Immediately about 300 birds settled near the comorant decoys. The comorants started to breed during the end of January in 1997, and 754 nests of the species were counted in April and found to be spread across the island. Accompanying the comorants, four species of Egrets also abandoned the garden and established nests on the island.

Key words: Great Comorant, Phalacrocorax carbo, breeding, conservation

National Science Museum, 3-23-1 Hyakunin-cho, Shinjuku-ku, Tokyo 169, Japan, e-mail nishiumi@kahaku.go.jp

Nishiumi, I. 1998. Provisioning in broods of Great Reed-Warblers is not related to offspring sex. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 300.

For polygynous animals in which variation in reproductive success among adults is influenced by parental investment, parents should allocate a greater proportion of their resources to individual sons than to individual daughters. Recently we showed that paternal feeding frequency was related to the brood sex ratio in Japanese Great Reed-Warblers, Acrocephalus arundinaceus orientalis. I observed parental feeding behaviour in nests where nestlings were individually marked on their heads. Neither parents preferentially fed the male nestlings in ten videotaped nests, while paternal feeding frequency was related to the brood sex ratio. Nestlings that begged highest and earliest and that gaped widest were the most likely to be fed. In such begging behaviours sons and daughters did not differ. There are some possibilities which might explain why fathers fed according to the brood sex ratio, instead of selectively feeding the sons. First, discrimination of offspring's sex prior to each feeding might cost. Second, undiscriminated feeding within broods might be beneficial through synchronous fledging for offspring guarding. Last, mothers might produce male-biased broods when they had signs of good male condition. The causal relationship between the paternal feeding and the brood sex ratio should be tested.

Key words: Acrocephalus arundinaceus orientalis, Japan, nestling behaviour, parental feeding, sex-biased provisioning

 

1School of Animal & Microbial Sciences, University of Reading, Whiteknights, PO Box 228, Reading, RG6 6AJ, UK, e-mail k.norris@reading.ac.uk; ²RSPB, The Lodge, Sandy, Bedfordshire, SG19 2DL, UK

Norris, K.J. & Johnstone, I.G. 1998. Ideal free oystercatchers: what is an ideal bird? In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 301.

The ideal free distribution provides the basis for understanding the dispersion of a predator across a food supply gradient. Most theoretical models of this distribution assume that an 'ideal' predator would attempt to maximise its rate of energy intake. Dispersion patterns are then likely to be determined by: (1) variation in prey density between patches, and (2) the number of competitors occupying a patch, since interference competition can depress intake rates. We present data from a two-year study of Oystercatchers Haematopus ostralegus feeding on Cockles Cerastoderma edule during winter. Using an optimality model, we found that birds did not maximise their rate of energy intake while feeding because they often avoided consuming the larger, more profitable cockles. This suggests that birds experienced costs associated with maximising their intake rate, in addition to time costs incurred while searching for and handling prey included in the model. We present a simple graphical model to show how such costs, together with a need to achieve a certain intake rate to avoid starvation, can combine to determine optimal intake rates. Ideal Oystercatchers do not, necessarily, maximise their intake rate.

Key words: Haematopus ostralegus, food supply, cockles, ideal free distribution, intertidal habitats

University of Bergen, Allégaten 41 36, N-5007 Bergen, Norway, e-mail Torbjørn.Paulsen@zoo.uib.no

Paulsen, T.R. 1998. Turdus spp.and Sorbus aucuparia seeds: Effect of ingestion on seed mass, germination and growth. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 30.1

The attention given bird-berry interactions has so far mainly concentrated on seed dispersal and the effect of ingestion on germination rates. In the present study, carried out on the western coast of Norway, the influence of ingestion by thrushes, Turdus spp, on factors such as seed mass, the pattern of seedling emergence in time, and first season growth is examined. Rowan Sorbus aucuparia seeds, half of which had been ingested, were sown either in soil, in pomes, or in bird droppings, or as two, tree, or four seeds sown together. Emergence rate and pattern of seedling emergence in time were monitored, and growth of seedlings (stem length, number of leaves, and length and width of longest leaf) were measured every four weeks throughout the first growth season. No effect was found on germination rates, but the gut passage increased seed mass by 9%. This weight change is explained by water uptake and increased food reserves. The pattern of seedling emergence in time also differed. This may be due to mechanical abrasion of the seed coat. At the end of the first growth season seedlings from ingested seeds were larger than the control seedlings, and this is discussed in relation to less germination effort and increased growth rates. In this mutual relationship the birds get high quality food and the trees get assistance in seed dispersal and seed nursing.

Key words: endozoochory, frugivory, mutualism

 

B077: A potential tool for documenting activities at cryptic grassland passerine nests

Northern Prairie Wildlife Research Center, 8711 37th St. SE, Jamestown, North Dakota 58401, USA, e-mail pam_pietz@nbs.gov

Pietz, P.J. & Granfors, D.A. 1998. A potential tool for documenting activities at cryptic grassland passerine nests. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 302.

Populations of many grassland birds have declined worldwide in recent decades. Low reproductive success may contribute to these declines. However, it is difficult to determine fates, causes of failure, and identity of predators at nests of these species. To record activities at grassland passerine nests, we developed a miniature camera system that included a black-and-white CCD board camera, infrared LEDs for night illumination, and a time-lapse VCR. In 1996 to 1997, prototype camera systems were used to monitor 65 nests of nine passerine species in several grassland habitats in North Dakota. Thirty-seven percent of these nests successfully fledged young, 35% were depredated, and 25% were abandoned. Predators identified included mice, ground squirrels, weasel, badger, red fox, coyote, and raptors. Fates of 300 nests without cameras were assessed using nest visits; 40% appeared to have fledged young, 52% appeared to have been depredated, and at least 6% were abandoned. Video data suggest that caution should be used in assigning nest fates and predator types based on information from nest visits alone. The camera system has potential for studying nest predation and parasitism, parental and nestling behaviour, and effects of human disturbance.

Key words: methods, breeding, nest fate, predation, camera

University of Innsbruck, Amthorstr. 4, A- 6020 Innsbruck, Austria, e-mail juergen.pollheimer@uibk.ac.at

Pollheimer, J. & Föger, M. 1998. Wintering strategies of tits Parus sp. in the European Alps. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 302.

Strategies of Passerines wintering in the European Alps are fairly unknown. In other parts of Europe low temperatures and restricted access to food were identified as predictors for changes in body mass and subcutaneous fat deposition. In a mountainous environment vertical gradients of resources and abiotic factors may impose physiological and behavioural adaptations. In our study wintering populations of five species of tits Parus sp. were investigated near Innsbruck (Austria, Europe). Tits were caught, colour-marked and observed weekly at feeders on three altitudes (750 m, 850 m, 1050 m asl.). Body mass and the degree of subcutaneous fat deposition were recorded for captured birds. Presence at the feeders was controlled by checking the individual colour marks during the observations. The body mass in tits was not influenced by air temperature. In Great Tit Parus major (n = 100, r_s= 0,39, P < 0,001), Coal Tit P. ater (n = 174, r_s= 0,14, P < 0,001) and Crested Tit P. cristatus (n = 36, r_s= 0,48, P = 0,001) air temperature predicted the amount of fat deposition. Great Tit and Coal Tit showed vertical movements during the winter. Ten changes between vertical levels were registered for Great Tit (1 ascent vs. 9 descents; G = 13,8, P < 0,001) and 44 for the Coal Tit (19 vs. 25; n.s.). Ascending Great Tits may follow changing resources and multiple movements of Coal Tits may be triggered by weather conditions.

Key words: winter biology, altitude, fat, body mass

Station Biologique de la Tour du Valat, Le Sambuc, 13200 Arles, France. e-mail brigitte.poulin@tour-du-valat.com

Poulin, B. 1998. Spatial heterogeneity and the passerine community in large reedbeds of southern France. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 303.

Large reedbeds cover extensive areas in southwestern France. Yet the spatial heterogeneity of this habitat and how it affects arthropod and bird distributions are poorly known. The community structure of passerines, their breeding success and food availability were studied within a 40 ha reedbed at the Vigueirat marshes, Camargue (08° 27’ N, 02° 75’ E). Plant structure (density, height and diameter of reed stems, plant composition), arthropod abundance (water traps and sweep net samples) and bird abundance (point count and mist-netting censuses) were determined at different locations within the study site. Abundance of most bird species increased along a gradient from the land offshore. Plant diversity increased and reed density decreased along the same gradient. Abundance of several arthropod taxa, including the most important to the birds as food source, was spatially correlated with bird abundance. An experimental study on nest predation suggests that nesting success is inversely correlated with reed density and food abundance. Because most passerines breeding in the reedbed habitat (e.g. Acrocephalus spp., Panurus biarmicus) do not defend a feeding territory, reproductive individuals can forage in areas of the reedbed where resources are plentiful, and nest in other areas where breeding success is potentially high. This spatial heterogeneity is an important aspect of the reedbed habitat and should be taken into consideration for elaborating conservation and management policies.

Key words: biodiversity, Panurus biarmicus, arthropods, community structure, Acrocephalus

 

1Finnish Game and Fisheries Research Institute, Evo Game Research Station, FIN-16970 Evo, Finland, e-mail hannu.poysa@rktl.fi; ²Department of Biology, University of Turku, FIN-20014 Turku, Finland; ³Department of Applied Zoology, FIN-00014 University of Helsinki, Finland

Pöysä, H., Milonoff, M., Ruusila, V. & Virtanen, J. 1998. Goldeneye females can not assess predation risk when selecting among previously unoccupied nest sites. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 303.

Nest predation is the major source of nesting mortality in birds and, thus, is likely to affect the evolution of reproductive tactics. Therefore, ability to select nest sites with reduced predation risk should be favoured. We studied experimentally whether Goldeneye Bucephala clangula, a hole-nesting duck, females are able to assess predation risk when selecting among new, previously unoccupied nest sites. In three study areas nest boxes were placed in pairs so that one was erected at the shoreline and the other inside the forest. The occupation of the nest boxes by Goldeneye females was studied from 1993 to 1997. Nest-predation risk was studied experimentally with dummy eggs placed in the nest boxes at the end of each nesting period. Predation risk in nest boxes that were occupied during the first four years of the experiment was not lower than that in unoccupied boxes. Among nest boxes that were occupied during the first four years predation risk did not affect the order of box occupation. These are the first experimental results to suggest that hole-nesting birds may not have evolved an ability to assess predation risk of new nest sites.

Key words: nest predation, nest site selection, Goldeneye, Bucephala clangula

Federal de Mato Grosso do Sul, Caixa Postal 210, Tres Lagoas, MS, Brazil, e-mail ajpiratelli@openlink.com.br

Piratelli, A.J. 1998. Understory bird communities from the east side of Mato Grosso do Sul state, central Brazil. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 304.

The ecosystem "cerrado" is being quickly degraded in Central Brazil, even before its biodiversity is known. A bird banding program was performed between August 1994 and December of 1996 in different vegetation types in the eastern side of Mato Grosso do Sul state. We obtained data on morphometrics, species diversity and abundance, feeding and moult and reproduction patterns. After 13468 net hours, 1076 individuals of 103 species and 21 families were captured. The most abundant families were Tyrannidae (24 species) and Emberezidae (18 species). The species with the largest relative abundance were Basileuterus flaveolus (8.11%) and Cnemotriccus fuscatus (6.87%). Locations with cerradao vegetation had the largest diversity index (3.63), followed by ciliary forest (3.32). For the 503 faeces samples there were nine feeding guilds, the most common being insectivores (62%) and frugivores (11%). Reproduction peaks occurred mainly between September and November (onset of rains). Flight and body feather moult occurred between January and March.

Key words: cerrado, conservation, biodiversity, forest

 

Hirosaki University, Department. of Bioproduction, Hirosaki University, Hirosaki 036 Japan, e-mail gobius@cc.hirosaki-u.ac.jp

Sawara, Y., Endo, N., Otsubo, M., Komatsu, R. & Sakuyama, M. 1998. Diurnal and nocturnal feeding of the Black-crowned Night-Heron in breeding season. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 304.

The Black-crowned Night-Heron Nycticorax nycticorax is basically nocturnal but can be seen feeding in the daytime during the breeding season. We investigated its feeding ecology in northern Japan using three main methods, i.e. the collection of regurgitates under the colony, counting the herons flying out of the colony in various directions, and tracing radio-tagged individuals. The main food was two categories of freshwater fish, i.e. paddy field fish and riverine fish. The paddy field fish were almost exclusively Loaches Misgurnus anguillicaudatus, which are nocturnal fish. Cyprinid fish species, such as Tribolodon hakonensis and Zacco platypus comprised the riverine fish in the heron's diet. These are diurnally active species. From the directions in which the herons flew out of the colony in the morning and evening, and the difference in the composition of the regurgitates between morning and evening, it was hypothesized that the herons switched their feeding sites daily, between day and night, according to the changes in the activity of the prey fish. The herons individually tagged with radio transmitters also behaved in accordance with the above hypothesis.

Key words: Black-crowned Night-Heron, Nycticorax nycticorax, feeding

Department of Biology, Hainan Normal University, Haikou 571158, China, e-mail pu3@hainnu.edu.cn

Shi, H.T. & Zheng, G.M. 1998. The relation between activity and diet of Temminck's Tragopan. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 305.

Temminck's Tragopan Tragopan temminckii is a near threatened species distributed mainly in China. The relationship between activity and diet had not been studied. We used radiotelemetry, and direct observation in Xianrenshan area, Guizhou Province, China from November 1993 to October 1994. Three tragopans were radiotracked, and 87 food items were found. Temminck's Tragopan preferred broadleaf and bamboo mixed forest closer to the valley (the forest edge). Tragopan used different kinds of habitat through the year, which was related to the food supplies. In spring, they occurred at the forest edge, rich with grass and bushes. In summer, they were in areas with good cover and abundant bushes. In autumn, they were in areas rich in fruits of Alangium chinensis and Macrocarpium chinensis. In winter they occurred in a variety of broadleaf and bamboo mixed forest. In winter and spring, as its food items were very abundant and widely distributed, so its home range is larger (0.081 to 0.229km²). In summer and autumn food items were less abundant and narrowly distributed, so their home ranges were smaller (0.047 to 0.089km²).

Key words: foraging, China, forest, territory

1Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China; ²Changbai Shan Natural Reserve, Jilin Province 133613, China

Li, S., Liu, X., Sun Y., Wang, L., Piao, Z. & Zhang, X. 1998. Breeding bird community in old selective stand of broad–leaved Korean pine forest. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 305.

Our work was conducted in 1994, at the Changbai Mountains in Jilin Province, northeast China. We studied the structure characteristics of breeding bird community at an old selective cutting forest, and compared with the virgin forest at the same altitude, the conifer-deciduous mixed forest. The vegetation investigation showed that the density, basal area and canopy coverage of the large trees (DBH > 13) did not change much after 17 years of selective cutting than recent selective cutting forest. However the shrubs developed much and higher density than that of virgin forest. The bird species number of old selective cutting forest (n = 33) was similar to that of the virgin forest (n = 31), with 26 same species. Adapting to the shrub’s environment, several new species found in the selective cutting forest, such as Radde's Warbler Phylloscopus schwarzi, Oriental Turtle-Dove Streptopelia orientalis, Scaly Thrush Zoothera dauma and Hazel Grouse Bonasa bonasia. As dead standing trees (snags) cleared when cutting, some hole-nesting birds were not recorded, such as the Ural Owl Strix uralensis and the White-backed Woodpecker Dendrocopos leucotos. The bird density in the old selective cutting forest was 92.7pairs/10hm², increased much than that of the recent selective cutting forest, and reached to the level of virgin forest (94.5 pairs/10hm²). The densities of the hole-nesting birds guild and canopy open-nesting bird guild were lower than those of the virgin forest, but the open-nesting birds at the shrub’s layer and ground had higher densities. The densities of foraging bird guild showed similar trends. The bird species diversity in the old selective cutting forest was similar to the virgin forest, and the similarity index of old selective cutting forest of the virgin forest was increased from 0.62, when the forest was recently cut, to 0.88 at present.

Key words: bird community, old selective cutting forest, virgin forest

1Department of Life Sciences & ²Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Israel, e-mail shochat@bgumail.bgu.ac.il

Shochat, E., Abramsky, Z. & Pinshow, B. 1998. Avian biodiversity in the Negev: Effects of semi-desert scrub fragmentation by planted woods. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 306.

Habitat fragmentation causes extinction of habitat-specialist species from small and isolated patches. Since 1956, large areas of semi-desert in the northern Negev, Israel have been fragmented by planted patches of trees comprising uniform sub-units of different ages. Today, this new landscape matrix consists of patches of scrub and primarily coniferous woods. This alteration in landscape pattern was followed by changes in bird diversity. We evaluated the abundance and distribution of birds in patches of scrub and woods using line transects. Specialist ground nesting species were absent from all planted areas and from small (< 50 ha) scrub patches. In woods, 91% of species richness could be explained by area per se. Four new immigrant species from the Mediterranean zone are apparently woods specialists, as their distribution was restricted to woods older than 13 years in patches greater than 300 ha. Our preliminary results suggest that the increase in species richness in wood patches is due to habitat heterogeneity; large patches contain a wider range of tree ages than small patches. Furthermore, we found a significant effect of tree age on species density and species richness. Species richness peaked in 30 year old woods.

Key words: extinction, habitat patches, immigration, landscape management, conservation

Department of Zoology, Farook College, PO Calicut, 673 632, Kerala, India

Shukkur, E.A.A. & Seedikkoya, M. 1998. Ecology and population movements of Cattle Egrets Bubulcus ibis, Little Egrets Egretta garzetta and Pond Herons Ardeola grayii. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 306.

Cattle Egrets, Little Egrets and Pond Herons are the most abundant birds in the paddy fields of Kerala, India. However, their breeding ecology and population movements are not well understood. We studied populations of these birds in North Kerala based on weekly total counts in twelve selected habitats. During the South West monsoon months of June to September the Cattle Egret is totally absent in Kerala and Pond Heron is confined to the paddy fields. The Little Egrets are very rare in this season and those sighted had yellow bills. During the North East Monsoon wet months of September to November these three species are seen foraging in every sort of habitats. From November onwards the number of birds increased in paddy fields with the largest congregation in the summer months of April to May in small patches of water in dry paddy fields. In the South West monsoon the egrets migrate to the eastern regions of Western Ghats for breeding. This is substantiated for the first time by our studies. Large formations of Cattle Egrets were not seen in the sky in the mornings and evenings during the June – September season. No herons could be spotted in Kerala except for a few in border areas.

Key words: India, monsoon, habitat

Department of Zoology, Farook College, P.O. Calicut, 673 632, Kerala, India

Shukkur, E.A.A. 1998. Ecology and populations of some wetland birds of Kerala, India. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 307.

Reclaimation of wet and marsh lands, spread of Kariba Weed Salvinia molusta and the water Hyacinth Eichhornis crassipes, more frequent droughts and increasing urbanisation have resulted in fragmentation of habitats, isolation of populations, lack of minimum viable population, lack of minimum viable area and genetic isolations in the case of many of the once common wetland birds of Kerala. The study was carried out in several jheels of North Kerala from 1979 to 1997 based on weekly counts of wetland birds. In several jheels the Pheasant-tailed Jacanas Hydrophasianus chirurgus have disappeared. The Water Lilly Nymphea stellata, its nesting plant, is replaced by S.molusta and E.crassipes. Gargany Teals Anas querquedula have been reduced to one fifth. The Lesser Whistling Teal Dendrocygna Javanica and the Little Cormorant Phalacocovax niger have lost three fourths of their winter and summer habitats. These birds and the Purple Moorhen Porphyrio porphyrio, which was a paddy pest, and the Bronze-winged Jacana Metopodius indicus suffer heavy summer mortality as do the Little Egret Egretta garzetta and the Cattle Egret Bubulcus ibis. These egrets migrate over to the Eastern parts of Western Ghats in the South West monsoon season for breeding.

Key words: India, monsoon, waterbirch, habitat

Department of Animal Ecology, Ecology Building, Lund University, S-223 62 Lund, Sweden, e-mail Henrik.Smith@Zooekol.lu.se

Smith, H.G. & Bruun, M. 1998. Effect of land use and food availability on starling breeding success in a heterogeneous agricultural landscape. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 308.

The population size of Common Starlings Sternus vulgaris has declined over large parts of Europe during the last decades. Reduced availability of pasture in the agricultural landscape may be one reason behind this decline. To investigate this, we established breeding colonies for starlings in southern Sweden, in agricultural landscapes with different availability of pasture, using each colony as an independent data point. Both nestling survival and growth was positively related to the availability of pasture near the breeding colony. Nestling survival and growth was positively related to parental food delivery rates. Parental food delivery rates, in turn, were positively related to the availability of pasture near the breeding colonies. There are at least two possible reasons for this relationship. First, food abundance was higher on fields covered by grass than on arable fields; this is also reflected in a higher availability of food to foraging adult birds. When the availability of pasture was high, parents spent more time foraging in this food-rich habitat. Second, when pasture was abundant, parents foraged nearer the breeding colonies, reducing travelling time. When the availability of pasture was low, parents spent more time in a variety of alternative habitats, such as roadsides and farmyards. This study therefore lends support to the contention that the reduction of pasture in the modern agricultural landscape may be a reason why starling population size has declined.

Key words: agriculture, parental care, starling, Sturnus vulgaris, food availability

Department of Vertebrate Ecology & Zoology, Gdansk University, Legionow 9, 80-441 Gdansk, Poland, e-mail biols@univ.gda.pl

Stempniewicz, L. & Iliszko, L.. 1998. Colony departure by young puffins Fratercula arctica at Bleiksoy, NW Norway. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 308.

Depending on feeding rate, young Atlantic Puffins leave the colony at different ages and stages of development. They depart to sea alone and at night. In August 1996 we studied timing of fledging and body condition of young Puffins caught in mist nets (flying) and ground nets (walking). Well developed birds from subcolonies on slopes departed on the wing and those from subcolonies on flat ground or in poor condition walked on foot. Flying fledglings had significantly longer wings and tails and tended to be heavier than birds departing on foot. They reached the sea about 1 hour earlier (peak: 2300 to 0000 h) and predominated during the first half of the fledging period. By departing the colony on the wing early in the night they could fly far away from coastal waters surrounding the colony and thus avoid risk of heavy predation of gulls. In contrast, birds walking on foot and then swimming, lost much time and energy overcoming dense vegetation, boulders and tidal zone on their way to the open sea. As a result they were still close to the seashore at dawn and were probably heavily predated. We suggest that type of nesting habitat (slopes or flat) influences breeding success of puffins also at and immediately after departure from colony by young birds.

Key words: Atlantic Puffin, Fratercula arctica, fledging, Bleiksoy, NW Norway

 

Latvian Ornithological Society, Latvia, e-mail putni@parks.lv

Strazds, M. 1998. Habitat selection of the Black Stork. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 309.

The Black Stork in Europe is a mostly lowland forest species with most of its breeding population concentrated in extensive woodlands SE from the Baltic Sea - Latvia, Lithuania, Belarus, Poland (32% of the world population or 45% of the European population). Species habitats requirements in Latvia were determined from analysis of about 247 territories holding more than 280 nests in Latvia. To assess the annual breeding success, a total of over 880 nest visits have been made from 1978 to 1997. In addition breeding phenology has been analysed and the lifetime productivity of various pairs evaluated. The analysed nests have been evaluated based on the above data as well as other available information such as access to the feeding site, forest coverage with a 3 km radius, nest site stability, and predation rate. Nests in optimal habitat show higher productivity therefore they deserve much greater attention from the conservation point of view. The importance of remnant optimal habitat in reproduction of Black Storks and the role of destruction of this habitat in the past as a cause of current population status in Europe is discussed.

Key words: Black Stork Ciconia nigra, Latvia, habitat selection

Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China, e-mail sunyh@sun.midwest.com.cn

Sun, Y. & Fang, Y. 1998. The mating system of Chinese Grouse Bonasa sewerzowi. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 309.

The Chinese Grouse Bonasa sewerzowi is an endemic and rare species, distributed in high mountain forests in western China. Little is known about its mating behaviour. During three breeding seasons, 1995 to 1997, we radio-tracked more than 40 birds at Lianhuashan Natural Reserve in Gansu Province. Males arrived on their territories in early spring. Flutter-jumping behaviour, which occurred most frequently in the morning, was used to advertise territory and attract a female. Females apparently choose territorial males for pairing. Pair formation started around late March, but the pair bond was relatively weak in the early stage. When together, the male and female were always within 10 m of each other, and the male allocated a lot of time to vigilance. Not all males had a chance to pair with females, perhaps due to variation in territory quality, including food resources, cover availability, and habitat diversity. Before copulating, both males and females showed a typical pre-copulation behaviour with head swaying. During the fertile period, most females were only with their partners. However, one radioed female was seen with 3 radioed males at different time in two days. Unpaired territorial males sometimes left their territories to compete for mating chances in the fertile period. We suggest the mating system of Chinese grouse was mainly monogamous and showed promiscuous trends, very similar to that of hazel grouse. Female choice appeared to be the main factor shaping social behaviour in the breeding season.

Key words: Chinese Grouse, mating system, sexual selection, promiscuity

 

Department of Zoology & Entomology, University of Natal, P/Bag X01, Scottsville, 3209 Pietermaritzburg, South Africa, TaylorB@zoology.unp.ac.za

Taylor, P.B. 1998. Ecology and conservation of the White-winged Flufftail. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 310.

The globally endangered White-winged Flufftail Sarothrura ayresi is known from very small populations in highland marshes of South Africa and Ethiopia, with occasional records from Zimbabwe where it may breed irregularly. It is poorly known, and the nature and extent of its migrations are unclear. In South Africa, studies in the 1990s have shown that small numbers probably occur annually at nine sites, where occurrences are apparently seasonal and the total known population may be 230 birds. One wetland is being rehabilitated and managed for this species, but other sites are seriously threatened by habitat degradation. In Ethiopia, after a long period with no sightings, the bird was rediscovered in 1995. During studies in 1996 the first breeding records were obtained at a small marsh where 10 to 15 pairs were recorded. Further studies in 1997 revealed the existence of a second site, with an estimated 200 breeding pairs, by far the largest population ever found, and the species is apparently present there throughout the year. Ethiopian breeding habitat and South African non-breeding habitat are very different in character, and the species has not yet been shown to breed in South Africa. Studies are continuing and new results will be included in the presentation.

Key words: Sarothrura ayresi, wetlands, conservation, breeding, migration

B100: The ecology of the Brown-headed Parrot Poicephalus cryptoxanthus

Research Centre for African Parrot Conservation, Department of Zoology and Entomology, University of Natal, Private Bag X01, Scottsville 3209, South Africa, e-mail perrin@zoology.unp.ac.za

Taylor, S. & Perrin, M.R. 1998. The ecology of the Brown-headed Parrot Poicephalus cryptoxanthus. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 310.

Although the Brown-headed Parrot is described as a common resident in South Africa and Mozambique its biology and ecology are virtually unknown. The species is increasingly vulnerable to habitat loss and fragmentation, and the avicultural trade. They occur in small groups, nest in winter in tree holes, incubate 2 to 3 eggs for 26 to 30 days and the fledged young occupy a leafy nursery in a large tree adjacent to water. The diet includes a wide range of foods which are used sequentially throughout the year and include seeds, figs, marulas, kudu berries and other fruits, millets, flowers of trees and palms, and they drink water daily. Local movements occur to exploit ephemeral food resources. The protein content of the diet increases during the breeding season, and recruitment success may be a function of food quality. Young birds may stay with their parents to learn about foraging and feeding. The species possesses a complex vocal repertoire. A mathematical model will be used to predict habitat suitability and carrying capacity in forests, and sustainable utilisation.

Key words: reproduction, diet, utilisation

1Forest & Forest Products Research Institute, P.O. Box 16, Tsukuba Norin, Ibaraki 305, Japan, e-mail tojo@ffpri.affrc.go.jp; ²Tokiwa University, Mito City, Ibaraki 310, Japan

Tojo, H. & Nakamura, S. 1998. Invasion of Red-billed Leiothrix Leiothrix lutea into Japanese forests and effects on native avifauna. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 311.

Exotic Red-billed Leiothrix Leiothrix lutea (RBL) have increased in numbers in the southern, western and central parts of Japan in recent years. Unlike most naturalised birds, main breeding habitats of this species are natural deciduous forests. We researched the breeding bird density by territory mapping method for an 8 ha plot in a deciduous forest on Mt. Tsukuba (876 m), a major breeding area of RBL in central Japan, in April to June of 1994 and 1995. RBL was the dominant species (350 to 400 pairs per 100ha) in both years. In 1995, six nests were found in a 1 ha area of the plot. In spite of the high breeding density of RBL, native avifauna showed normal total breeding density (approx. 600 pair / 100ha) and number of species (22 to 26 species), compared with similar Japanese deciduous forests. Therefore, we suggest that RBL have invaded to Mt. Tsukuba without severe competition with native bird species.

Key words: invasion, naturalisation, Red-billed Leiothrix

 

Zoological Museum, Moscow Lomonosov State University, Bolshaya Nikitskaya 6, 103009 Moscow, Russia, e-mail tomkovic@1.zoomus.bio.msu.ru

Tomkovich, P.S. 1998. Differences in competition intensity of Calidris sandpipers on wintering versus breeding grounds: Indirect evidence. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 311.

Among long-distance migratory waders it is unclear whether birds are more competitive on their breeding or wintering grounds or, indeed, if competition even exists. My thesis is that competition does exist and that it should be most intense in congeneric species with like morphologies. A comparison of the distributions of several closely related Calidris species shows much greater overlap in breeding ranges than in their wintering ranges. In the few instances where nonbreeding ranges of closely related species do overlap, their respective preferred habitats are markedly different (e.g., C. temminckii, C. subminuta, C. ruficollis in SE Asia) or birds show character displacement (e.g., C. canutus and C. tenuirostris in Australia). These factors tend to favor the nonbreeding season competition hypothesis and allow me to do that: (1) Species composition is more structured on winter quarters than on breeding grounds. (2) Winter ranges of Calidris species normally are more stable than breeding ones and, as a result, current winter ranges better indicate areas of former species distribution.

Key words: Calidris, competition, ranges, species composition

ORSTOM, 2 allee des bruyeres, 78310 Maurepas, France, e-mail treca@compuserve.com

Treca, B. 1998. Birds fashion savannas. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 311.

It is well known that bird populations are linked with the quality of their environment. But birds may also fashion their own environment by spatially redistributing fertilisers in their droppings below trees in which they perch (80% of the amount of Nitrogen that will be recycled by above ground vegetable litter, 64% of Phosphorus), by favouring germination of trees' and shrubs' seeds through digestion of fruits and by scattering these seeds in spots that have already been enriched. In a Senegal dry savanna, Boscia senegalensis has the best regeneration level among ligneous species, especially under Acacia trees' cover, Lamprotornis chalybaeus being the most efficient spreader. That bird, by swallowing, digesting fruits of Boscia senegalensis and defaecating seeds, increases their germination capacity (measured in laboratory) from 28% to 66.7%, half of the seeds germinating within 5.4 days instead of 16. Birds may also eat fruits of imported trees species and spread them away as shown by Azadirachta indica near roads. In the absence of elephants, dromedary and fruit-eating bats, birds are now among the main actors of landscape changes together with man and cattle.

Key words: Lamprotornis chalybaeus, Azadirachta indica, fertlisers, seeds dispersal, Boscia senegalensis

R. Vides-Almonacid¹ , H. Korn² , M.E. Morales, M. Bustos, S. Nadra & A. Yapur

1Fundacion Miguel Lillo, Av. Aconquija 2920, 4107-Yerba Buena, Tucuman, Argentina, e-mail ecolotic.avian@networld.com.ar; ²International Academy for Nature Conservation, Isle of Vilm

Vides-Almonacid, R., Korn, H, M.E. Morales, M. Bustos, S. Nadra & A. Yapur. 1998. Selection of birds as ecological indicators to management of a neotropical montane reserve. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 312.

We propose a method for selection of birds as ecological indicators for management of neo-tropical reserve in northwest of Argentine. Changes in bird community structure and composition, as consequence of habitat modification, was evaluated in two sample periods (1991 and 1996-97). Point count surveys showed a significant decrease in abundance of specialised forest birds in cropland and early secondary growth habitats, and an increase of open habitat specialists. Within the different study sites we observed gradients in abundance for the 16 most common bird species, according to increasing complexity of the habitat. With this information, we derived six theoretical models to describe the habitat use gradients of bird species. Then, this models were analysed in a second sample period (1996-97) to validate the first results. Criteria for individual bird species and guilds as ecological indicators were derived. Based on these results we suggest the buffer zone design for the reserve and the guidelines for a habitat and biodiversity monitoring program.

Key words: ecological indicators, buffer zones, conservation, biodiversity, modelling

 

Institute of Biology, LV-2169 Salaspils, Latvia, e-mail ring@acad.latnet.lv

Viksne, J. 1998. Fifty year population dynamics of the Latvian Black-Headed Gull Larus ridibundus. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 312.

Detailed studies of populations are necessary to understand dynamics of the Black-headed Gull (BHG) during 20th century. The study included country wide censuses, analysis of ringing and recapture materials, studies of productivity on fenced plots, diet and feeding flights on Engure Ramsar site since 1958. Latvian BHG population increased from 10000 pairs in the 1940s to 110000 in 1986, then declined to 40000 in 1994. Population growth was promoted by synathropization of the species and unlimited feeding opportunities in 1950s-1960s. Natal dispersal from old colonies up to 500 km apart was essential for the growth of new colonies. Population growth coincided with an increase of anthropogenic food from 0% in 1959 to 53% in 1971 and with an increase of feeding flight distances (up to max 70 km, mass-scale observed at 40 km). The last coincided also with fishing regulations decreasing feeding opportunities close to colonies, and with the beginning of productivity decline (from 1.36 fledglings/pair in 1974 to 0.5 in 1982, P <0.001), however, population growth continued. A dramatic decline on Engure from 34000 in 1986 to 10500 pairs in 1997 was caused by further loss of possibilities to get anthropogenic food. Also American mink Mustela vison is responsible for recent BHG decline.

Key words: Common Black-headed Gull, dynamics, productivity, diet, Latvia

1Institute for Systematic Botany and Plant Geography, Heidelberg, Germany, e-mail: uwittman@aixterm1.urz.uni-heidelberg.de; ²Zoological Research Institute and Museum A. Koenig,Bonn, Germany

Wittmann, U. & Schuchmann, K.-L. 1998. Hummingbirds and Gesneriaceae: Specialisation versus Generalisation. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 313.

The Gesneriaceae (c. 3000 spp.) are mainly tropical plants with many species pollinated by hummingbirds. Interactions of this complex bird-flower system are poorly understood. For many gesneriads the degree of ornithophily and the visitor range is not known. We present the results of a one-year study conducted in an Ecuadorian lowland rainforest (Chocó, Pacific side) on the local hummingbird guild, dominated by members belonging to the Phaethornithinae, and their gesneriad food plants. To estimate energy budgets as a measure of pollination strategies and possible bird-flower adaptations the following data were assembled: Phenology (onset of flowering, fruit production), circadian nectar production, corolla lengths, trochilid visitation rates, energy consumption. Further methods included the mistnetting of hummingbirds to obtain morphological information and to collect pollen samples from their beaks and feathers. Pollen was identified by scanning electron microscopy. Not all sympatric gesneriads with overlaps in anthesis show specific morphological traits to avoid pollinator competition. Many gesneriads increase their optical attractiveness for hummingbirds by red leaf patterns ("phyllo-flagging", e.g., Dalbergaria). Corolla morphology and high-reward nectar production indicate specialisation patterns between gesneriads and trochilids regarding pollination. Mass flowering in terrestrial gesneriads, e.g., Besleria and Gasteranthus, with relatively unspecialised flowers and low-reward nectar production, is another evolutionary pattern for understory species to attract hummingbirds ("colour bang effect"). Hummingbirds react to this floral phenology by changing their feeding behaviour namely temporal territoriality instead of traplining, resulting in higher pollination rates for terrestrial gesneriads.

Key words: Gesneriaceae, hummingbirds, Phaethornithinae, specialisation, generalisation

Department of Biology, Beijing Normal University, Beijing 100875, China

Zhang, Z.W. Zeng, H.M. & Zheng, G.M. 1998. Home range and habitat selection of Brown Eared-Pheasant in the spring. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 314.

Studies on home range and habitat selection of the Brown Eared-Pheasant Crossoptilon mantchuricum have been conducted in Luyashan Nature Reserve of Shanzi Province, China, from February to May in 1996. Radiotelemetry and field observations were used in this study. The Brown Eared-Pheasant starts to select mates in mid- March and the pair begins to hold a territory for breeding. In the breeding season, the home range is 2.20 to 2.79 ha and it varies with the age of the birds, the breeding season, the type of habitats and the food supply. Larger home range occurs in the young birds with poor food supply. The home range is larger in the period of pair formation than in any other breeding stages. Brown Eared-Pheasant shows a strong tendency of habitat selection in the spring. There are significant differences between the habitat samples and random chosen sites (Hotelling T² test, n = 52, P < 0.001). Among the 32 habitat variables examined, 9 were found to affect the habitat selection, including the slope, distance from the mountain ridge, distance from the water, food abundance, amount of bushes, percentage of bare ground, the cover at 51 to 100 cm, 1 to 2 m, and 2 to 5 m.

Key words: Galliformes, endangered species, radio-tracking, vegetation, conservation