Anderson, M.D. 1998. The Karoo large terrestrial bird survey. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 342.

The eastern Karoo supports ten species of large terrestrial birds, several of which are endemic to southern Africa (including the Ludwig's Bustard Neotis ludwigii and Karoo Korhaan Eupodotis vigorsii). Five species are listed in international and national red data books, with the dominant threat being collision with powerlines. The eastern Karoo is particularly important for the Blue Crane Grus paradisea, supporting ± 25% of the world population. Despite the present threatened status of these ten species, there is little information about population trends. These are investigated during this bi-annual survey, which commenced during winter 1995 and involves members of the Karoo community. Birds are counted from a vehicle along twenty-five 70 km road transects during mid-summer and mid-winter. Thus far a maximum of 19578 birds have been counted, comprising mainly of White Storks Ciconia ciconia. More Blue Cranes and Karoo Korhaans are recorded during winter, the result of an influx of birds and/or change in social behaviour. Blue Crane flocks of more than 100 individuals are frequently observed during winter. The Secretary bird Sagittarius serpentarius has increased from 0.71 to 1.90 birds per 100 km during the survey period, possibly the result of a change in farming and locust-control practices during recent times. The survey will ultimately provide information about population trends of these Karoo bird species.

Key words: road survey, monitoring, Africa, conservation

 

Carlini, A.R., Soave, G.E. & Coria, N.R. 1998. Trends in size and breeding success of Adélie Penguins Pygoscelis adeliae at King George Island. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 342.

As part of a monitoring study of an Adélie Penguin colony, birds occupying nests with eggs and chicks at fledging were counted in most years from 1987 to 1996, at Stranger Point, King George Island, Antarctica. During the study period the breeding population showed a continuous decrease from 1987 to 1990, followed by a rise between 1990 and 1992, and dropped again in 1995 and 1996. Since 1987 the total number of breeding pairs decreased 45.5%. This drop (expressed as percentage of initial size) was more marked for bigger breeding groups (more than 400 pairs) than for smaller ones (less than 200 pairs). The number of chicks at fledging followed a similar trend to that of the breeding population, the smaller number occurring in 1996, when it was 60.4% lower than in 1987. The decreases in both population parameters of Adélie Penguin could be due to the reduced population sizes of krill observed in the Antarctic Peninsula Region since 1985.

Key words: Pygoscelis adeliae, population, krill, King George Island, Antartica

 

Chang, F., Zheng, G., Zhou, X., Zhang, H. & Yang, J. 1998. Resource partitioning: Crimson-Bellied Tragopan and other birds. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 343.

The fieldwork was performed in Wolong Nature Reserve (30° 45’ N 102° 52’ E, 31° 25’ N 103° 24’E), Sichuan Province, China from November 1994 to September 1995. Cluster analysis was used to assess community structure and it's seasonal change of Tragopan temminckii and other birds. Niche analysis was used also to understand the resource partitioning in this community. The competitors or potential competitors of Tragopan temminckii are Ithaginis cruentus, Pucrasia macrolopho, Garrulax lunulats and Garrulax ocellatus in winter. In spring and summer competitors are Ithaginis cruentus, Pucrasia macrolopho, Monticola solitarius, Myiophoneus caeruleus and Garrulax maximus. The competitive status of Tragopan temminckii differs with species and season. They used different resources.

Key words: community, biodiversity, China, population

 

Dean, W.R.J. 1998. Stochastic variation in population density of birds in Karoo shrubland. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 344.

The density of birds in Karoo shrubland is low and characterised by high variance. The density of birds in shrubland at Tierberg, Prince Albert, was examined using counts on 1 km transects (n = 1034) from 1988 to 1993. Questions addressed were: (1) Do some species have regular seasonal movements to the area, differing only in relative abundance? and, (2) How stable are populations of resident species? Only 29 species (of 69) were recorded on more than 1% of the counts. Estimated density of all birds was 32.7 ± 32.8 (S.D.) birds.km^-2, of resident birds 24.4 ± 21.0 birds.km^-2 and of nomads 1.9 ± 11.7 birds.km^-2. The standing crop biomass of all birds averaged 1593.8 ± 3031.8 g.km^-2. Resident species seemed constant in species richness, but less stable in density, due not only to the dispersal or immigration of young, but also probably to movements on a local or landscape level. Some nomadic species have regular seasonal movements to the same area every year, whereas others are more erratic in the southern Karoo. The relative abundance of all nomads differed markedly from year to year, probably in response to the patchiness in time and space of certain resources.

Key words: nomads, population, Africa, arid habitat

 

Degnan, S.M., Kikkawa, J. & Owens, I.P.F. 1998. Are morphometric traits heritable in the silvereye? In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 344.

Morphological divergence of white-eyes Zosterops on islands is well known. As with other cases of island differentiation, questions remain as to whether the changes are genetic in origin, or simply reflect phenotypic responses to novel environments. This is primarily because heritabilities of the relevant traits have not been determined. On the southern Great Barrier Reef, the Capricorn Silvereye Z. lateralis chlorocephala has morphologically diverged from the mainland race in just a few thousand years. Using measurements collected over 15 generations on Heron Island, we estimated narrow-sense heritability of seven morphometric traits that show significant size increase in the island race. Only for weight and bill depth are heritabilities significantly greater than zero, those for remaining traits (tarsus, wing length, tail length, culmen, bill width) are extremely low. Comparison of parent-offspring, full-sib and half-sib estimates tentatively suggests that the low heritabilities are not all due to excess environmental effects. Although this needs to be tested by cross-fostering experiments, alternative explanations are that: (1) heritabilities genuinely are low for these characters, or (2) heritabilities are low except following significant environmental change (e.g. a cyclone or arrival of a competitor) when heritability may increase in response to new selection pressures.

Key words: heritability, white-eye, morphometrics, Zosterops, island

 

Diehl, B. 1998. Biennal cycles in populations of passerine birds in a patchy habitat during succession. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 345.

Cyclic changes in abundance are known for boreal species, and they are associated with cycles in food availability. Biennual cyclicity, however, is rarely reported for birds. I have found that two-year cycles are common in the dynamics of many passerines when it is analysed on a small spatial scale. The study on variation in numbers of passerines was conducted over 30 years since 1964 on a 44-ha plot of shrubby grassland representing a mosaic of habitats of differential suitability to birds. All these habitats were in various stages of forest succession. The mapping method was used to estimate numbers of birds. Total abundance showed increasing and declining trends. For most species (out of ca. 40) 2 year cycles were superimposed on these multi-year trends in both granivorous and insectivorous species. Cyclic pattern was most pronounced for species represented by small and medium numbers of individuals, as well as for dominant species but only in less suitable habitat patches, where their densities were low. It is argued that trends in numbers of birds were determined by successional changes in the habitat structure, whereas biennial cyclicity resulted from competitive interactions among birds. These findings may contribute to a better understanding of the functioning of bird populations and communities in variable habitats.

Key words: habitat structure, population trends, avian communities, competition

 

Enoksson, B. 1998. Winter survival in the European Nuthatch Sitta europaea: Temperature is more important than food. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 345.

Winter (November to March) survival was studied in colour-ringed European Nuthatches Sitta europaea for ten winters in South-central Sweden. The European Nuthatch is a very sedentary bird and pairs maintain territories the year round. Juveniles establish territories in late summer. Territory size is similar in adults and juveniles, and varies inversely with food density in autumn. Winter is the season with lowest survival, varying between 25 and 100%. Juveniles had lower winter survival rate than adults. Supplemental feeding during autumn resulted in smaller territories, but did not improve survival during winter. Instead, the most important factor affecting winter survival was temperature.

Key words: nuthatch, winter, survival, food density, temperature

 

Ens, B.J. 1998. The effect of shell-fishing on Oystercatcher populations in the Dutch Wadden sea. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 345.

Is it possible to predict the effect of a certain amount of shell-fishing on the population dynamics of the Oystercatcher? Huge numbers of Oystercatchers winter in the Dutch Wadden Sea. Cockles and mussels are the staple food at that time of the year. The stock of these bivalves is quite variable from year to year as severe winters may take a heavy toll and recruitment may fail for a number of years in a row. Over the last decades, commercial fishing of cockles and mussels by large boats has increased. In this period, the intertidal mussel beds, with a total surface of 4000 ha and harbouring a major share of the 200000 Oystercatchers in the Wadden Sea have disappeared and not recovered. This is despite the implementation of a new shell-fishing policy. Almost certainly as a result of this, the mortality of Oystercatchers, which also reflects on the severity of the winter, has increased. Populations breeding around the Wadden Sea are declining. This series of events offers a unique possibility to test various models that have been developed to predict the population dynamics (especially the overwinter survival) from the distribution of individual birds over the feeding grounds.

Key words: individual behaviour, population dynamics, shell-fishing, modelling, conservation

 

Grinkov, V.G. & Kerimov, A.B. 1998. The maintenance of plumage colour variation in the Pied Flycatcher Ficedula hypoleuca males. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 346.

The nature of high variation of the male plumage colour in the Pied Flycatcher is not yet known in spite of detailed investigation. The qualitative and quantitative components of male fitness such as breeding date, clutch and brood size, weight, fat contents and physical condition of mates and descendants have been estimated in breeding population on Ladoga Lake Coast in north-west Russia (93 males, 78 females and 369 nestlings from 71 nests were analysed). Fecundity was not related to male colour. Both bright and pale males benefited in weight and physical condition of fledglings and mates, while intermediate coloured males benefited less by these measures. Marginal phenotypes used alternative reproductive strategies differing in patterns of temporal allocation of reproductive efforts and mating preferences. These strategies were suggested to give benefits. On the contrary, mixed strategy of intermediate coloured males does not seem to be successful. The phenotype balance is maintained by disruptive selection supplemented by interpopulation exchange.

Key words: Russia, polymorphism, fitness, reproductive strategies, phenotype

 

Ivanovsky, V.V. 1998. Changes in composition of the bird fauna in the bogs of the Poozerye region over the last 20 to 25 years. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 346.

Bogs cover 3% of the territory of the Belorussian Poozerye region, being the landscape type least influenced by human activities in the northern part of Republic. Nevertheless, certain natural changes have taken place in their relatively stable bird fauna. The data collected by the authors of the present paper from 1975 to 1997 have been compared with those presented by V. Duchits for 1958 to 1969. Out of the 98 bird species recorded in the bogs, 63 were nesting species, of which 45 were regular breeders. The present authors were able to add 31 new species to the existing list, but rare species such as Osprey Pandion haliaetus, Short-toed Eagle, Peregrine Falcon Falco peregrinus, Hen Harrier, Golden Plover Pluvialis apricaria, Greenshank Tringa nebularia, Whimbrel Numenius phaeopus and Jack Snipe Lymnocryptes minimus are likely, to have bred in the area before. In the course of the last ten years a number of new breeding bird species had appeared in the bogs. These include Goldeneye Bucephala clangula, Redshank Tringa totanus, Ruff Philomachus pugnax, Black-tailed Godwit Limosa limosa, Black-headed Gull Larus ichthyaetus, Herring Gull, and Common Gull Larus ridibundus.

 

Kruszewicz, A.G. & Dyrcz, A. 1998. Parasites and sexual selection in warblers Acrocephalus spp: Preliminary report. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 346.

Aquatic Warblers Acrocephalus paludicola and Sedge Warblers Acrocephalus schoenobaenus are two sibling species that live in very similar habitats in the Polish landscape. Aquatic Warblers have a promiscuous mating system, while Sedge Warblers are mostly monogamous (only 5-7% of males are polygynous). The occurrence of intestinal parasites in these two species has been analysed over the last two breeding seasons (1996 and 1997), in Biebrza Valley (Northeast Poland). Intestinal parasites were very common in the Aquatic Warbler population (62.3% birds were infested by: Coccidia - 27.7%, Nematoda - 23.3%, and Cestoda and Trematoda). In the sibling monogamous Sedge Warbler intestinal parasites were less frequent. The only parasite that occurred in Sedge Warbler adults was Isospora lacazei (33%). What is more, they show a low level of parasitemia. This suggests that parasite load may impact on polygynous mating system evolution in Aquatic Warblers and supports the hypothesis that parasites may be the important factor influencing the evolution of mating systems in passerine birds.

Key words: parasites, Acrocephalus, mating, sexual selection, Isopora

 

McCann, K.I., Wilkins, H.J. & Morrison, K. 1998. Population dynamics of the Wattled Crane Bugeranus carunculatus in South Africa between 1982 and 1997. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 347.

In the latest IUCN/SSC crane specialist group publication "The Crane - Status Survey and Conservation Action Plan" the Wattled Crane Bugeranus carunculatus is listed as "critically endangered" in South Africa. The reason for this has been its steady decline in breeding numbers over the last 15 years. The key populations of Wattled Crane in South Africa, in the provinces of KwaZulu-Natal, Mpumalanga, Free State and Eastern Cape, declined by an average of 57.6% between 1982 and 1997, with a resulting decline in breeding pairs from approximately 135 pairs to 75 pairs during the same period. Wattled Crane nesting activity has been recorded in all months of the year between April and December. The current 1997 population of approximately 250 individuals has an average hatching success of 82.0%, significantly higher than the 1982 success of 55.1% and a breeding productivity or fledging success rate of 58.0%, which is not significantly different from the 1982 fledging success of 62.2%. The key to successful Wattled Crane conservation is the integrated management of the remaining breeding pairs and nesting sites in conjunction with our crane custodians, the private landowners.

Key words: Wattled Crane, South African population, critically endangered, breeding biology

 

Monteiro, L.R., Feio, R., Wilson, L., Hewitson, L., Pereira, J., Ramos, J.A., Sola, E., Monteiro, P., Furness, R.W., Tavares, A. & Neves, V. 1998. Using raft counts to census Cory’s Shearwater Calonectris diomedea. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 347.

Cory’s shearwater Calonectris diomedea is a species of European conservation concern. Although census and monitoring of the population are necessary, these are troublesome because it breeds mostly in cavities on inaccessible sites and it is customarily active inland only by night. However, birds gathering in rafts around colonies awaiting the onset of darkness to come ashore offer a basis for estimating poorly known population levels poorly explored yet. We tested the potential of rafts counts as a census method by assessing potential confounding effects of: (1) Observer bias, light and visibility in count accuracy. (2) Diurnal and short-term variability in raft size and its correlation with environmental conditions (wind speed and wave height). (3) Medium- to long-term variability in raft size and its correlation with moon phase and phase of the breeding cycle (mating, prelaying exodus, incubation and hatching). We also derived a relationship between numbers of breeding pairs and individuals rafting at a given colony. Results confirmed raft counts as a reliable census method and it was employed in the first complete census undertaken in the Azores archipelago in 1996. Preliminary results for this archipelago yield a total of 365.729 individuals in rafts (95% confidence interval = ± 16.623), corresponding to ca. 112.500 breeding pairs and about 74% of the borealis subspecies total and 52% of the world total population.

Key words: Procellariiformes, conservation, Azores

 

Nankinov, D. 1998. Migration, seasonal and spatial distribution of Manx Shearwater Puffinus puffinus in the Black Sea basin. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 348.

The migration, seasonal and spatial distribution of Manx Shearwater in the Black Sea basin are complex depending on the annual cycle, biology, migrations and the changes in numbers of their fish-prey species. Predominant prey species of Manx Shearwater here are Black Sea anchovy Engraulis encrasicholus ponticus, Azov anchovy E. e. maeoticus, European sprat Sprattus sprattus and Silverside Atherina mochan pontica. In spring Manx Shearwaters head mostly for the northwestern, the northern and the eastern part of the Black Sea, they remain for a long time in the Kertchenski Strait, and sometimes they follow fish shoals near the western seashore. With the onset of warm weather they migrate out into the open sea and cover large areas. At the end of summer and in autumn they penetrate more often into the Azov Sea. In autumn Manx Shearwaters spread over the whole water system and then migrate to the coasts of the Crimean Peninsula and Caucasus, where the wintering concentrations of Black Sea anchovy and Azov anchovy are found. Manx Shearwaters visit the Black Sea basin in large numbers in summer and in spring, where respectively 53.73% and 46.01% of the individuals observed over the course of the year have been recorded. Numbers are highest in April (32.74%) and June (27.06%), and then gradually diminish in number until winter when numbers of the Manx Shearwaters in the Black Sea are lowest.

Key words: seabird, fish prey, distribution

 

Nankinov, D. 1998. Procellariiform seabirds (Order Procellariiformes) in the Black Sea and the Azov sea. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 348.

The most numerous species of the Order Procellariiformes in the Black Sea and the Azov Sea is Manx Shearwater. It is represented by 3 subspecies: Yelkouan (Manx) Shearwater Puffinus puffinus yelkouan or P. yelkouan yelkouan, Balearic (Manx) Shearwater P. p. mauretanicus and Atlantic (Manx) Shearwater P. puffinus puffinus, the former being prevalent, while the latter two have been each observed only once. Manx Shearwater pairs nest on the islands and coasts of Bulgaria and Ukraine, on steep rocky coasts of the Kaliakra Cape and the Crimean Peninsula, and the island of St. Ivan, where a large population of European (Old World) Rabbit Oryctolagus cuniculus occurs. Manx Shearwater numbers and distribution in the Black Sea and in the Azov Sea depend directly on the migration of fish shoals, which the birds follow, mostly those of Black Sea anchovy and Azov anchovy, European sprat, Silverside and others. Cory`s Shearwater Canonectris diomedea has been observed in the Black Sea about a dozen times. In the past it penetrated more commonly from the Aegean Sea through the Bosphorus. It was observed once far from the sea, on a reservoir in the interior of the continent. Storm Petrel Hydrobates pelagicus was first observed in the Azov Sea on 7 October 1911, and thereafter on 30 October 1949 near the Caucasian coast and in July 1970 on the Bulgarian Black Sea coast. The Procellariiform sea birds use the aquatory of the Black Sea and of the Azov Sea predominantly during their foraging trips. The greatest danger for them are the various poisons and industrial and domestic waste from Central and Eastern Europe, which, enter these seas in large rivers. During the active commercial fishing period some Procellariiform sea birds perish in fishing nets.

Key words: Puffinus, fish prey, distribution

 

Nankinov, D. 1998. State of the Black Sea population of European Shag Phalacrocorax aristotelis. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 349.

Isolated nests of European Shag have been found in Ukraine (near Cape Tarhankut, Ak- Mecher, Sevastopol, Balaklava, Cape Aja, on Ai-Dalari near Cape Gurzuf, on Baklanii kamen near Karadag, Cape Opuk, Skal Korabli, and earlier on the island Berezan in the firth of the river Dnepar and the island Zmeinii), in Bulgaria (Tjulenovo, Iailite, Rusalka resort, Eni Kulak, Cape Kaliakra and Zelenka), in Turkey (Trabzon, Tirebolu, Giresun, Ordu, Terme, and in the past near Istanbul). Population numbers vary over 10 to 15 years between 520 and 1500 pairs with 500 to 1300 pairs in Ukraine, and between 10 and 100 pairs in Bulgaria and Turkey. The colony on Cape Tarhankut in Crimean is the largest, reaching up to 1200 pairs. They migrate over hundreds of kilometres in the coastal area, and penetrate the Sea of Marmora and to inland reservoirs. Negative influences on numbers include direct killing by people, disturbance by tourists, death in fishing-nets, pollution of the Black Sea with different kinds of poisons and petroleum products, decreasing of the fish numbers, high numbers of Herring Gull Larus argentatus. Some of nests are within protected areas. The species is formally protected in Bulgaria and is included in the Red Books of Bulgaria and Russia.

Key words: seabird, Herring Gull, demography, conservation

 

Narushin, V.G. 1998. Oology as a sub-discipline of ornithology: Principal methods and criteria. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 349.

Avian eggs may be appropriate for investigating problems in population biology, morphology, ecology, reproduction, systematic, and microevolution. This is due to the simplicity of collecting eggs, the finite term of laying, and convenience of measuring. Based on the long-term investigations the following criteria were found to be the most appropriate describing egg morphology. (1) Egg shape: The method for description the egg shape consists in estimation of its geometrical formula which is defined in polar co-ordinates (r, v) as: r = L (cosv)ⁿ (A) in which n is a function of egg length L, and maximum diameter B. An inclination of egg shape from its theoretical profile (A) is characterised by the indices of elipticity and conicity. (2) Egg dimensions: This criterion includes egg mass which is measured directly, egg volume V, and surface area S, which may be calculated by the formulae: V = 2.1L³/(2805.6(L/C)⁶ )+1) (B), S = 0.08C^3.2L^-1.2 (C), in which C is the length of egg long circumference. (3) Shell strength: This criterion is characterised by shell thickness and/or by the ratio of shell weight to egg surface area. Both thickness and shell weight are measured directly. (4) Shell colouring: An egg may be characterised by its colour and/or shell tracing which may be like spots, lines or spots and lines together. The quantitative characteristic may be the area of tracings at a given part of the shell. The area may be measured according to the Monte Carlo method.

Key words: egg measurement, methodology, shape, brood parasitism

Centro de Zoologia Aplicada, Universidad Nacional de Cordoba, C.C. 122, Cordoba 5000, Argentina, e-mail navarroj@gtwing.efn.uncor.edu

Navarro, J.L. & Martella, M.B. 1998. Population biology of Rhea americana in Argentina: Implications for conservation. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 350.

The Greater Rhea is a ratite of economic and conservation importance. We studied two closed populations of rheas in Cordoba province, from 1992 to 1996. The onset and end of breeding showed considerable variation (5 September to 2 November and 30 October to 30 March, respectively). The average clutch size ranged from 20 to 35 eggs and the hatching success ranged from 11.3% to 24.9%. These values are similar or slightly higher than those of wild populations of rheas. However, eggs produced per female (11 to 35) and hatching success were lower than those registered in farms and zoos. Heavy rains, hail and predation of eggs and chicks were significant sources of loss. A substantial and variable proportion of males were not successful in producing chicks (nest desertion is common and some males do not nest). These variations in the proportion of operative incubating males modify the growth rate of populations of rheas through a change in the birth rate. We conclude that healthy populations of rheas can be preserved in modified environments and juveniles produced can be translocated, used for captive breeding programs or for sustainable use in ranching or farming schemes.

Key words: Argentina, population biology, productivity ratites, ratite, Rhea

Evolution Theory Department, Biological Faculty, Lomonosov Moscow State University, 119 899, Russia, e-mail Obukhova@1.Evolut.bio.msu.ru

Obukhova, N.Y. 1998. The phenotypic structure and longevity of a synanthropic dove Columba livia in Moscow. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 350.

Synanthropic populations of doves in Moscow are polymorphic in colour patterns, with three widespread phenotypes (wild type doves, melanistic and intermediate) and three rare phenotypes (red, albino, violet). The frequency of widespread phenotypes in different districts is constant, while the frequency of rare phenotypes ranged from 1.3 to 9.3%, and rare phenotypes showed no tendency of extinction. The main fitness component, the longevity, has been tested by monitoring individually recognisable doves over ten years. The average longevity of doves is about two years, with a maximum of seven years for one individual. Breeding starts from one to two years old. There are no essential differences in longevity among all six phenotypes. The same holds for differences among populations inhabiting different districts. Most melanised colonies are characterised by decreased genetic variability mainly due to the lack of rare phenotypes. The albino is predominant among aberrant forms. The aberrant colour patterns have no advantages in longevity. The preservation of these patterns is provided by combining genes and by peculiarities of behaviour. Thus, the town populations of doves are subject to mechanisms of maintaining genetically controlled variation in the patterns.

Key words: Russia, phenotype, colour variation, longevity, polymorphism

Population Biology Group, Dept Genetics, Eotvos University, Budapest, Muzeum krt. 4/A, 1088 Budapest, Hungary, e-mail pasztor@ludens.elte.hu

Pásztor, L., Meszéna, G., Kisdi, É. & Tóth, Z. 1998. Robust models for interpretations of brood-size manipulation experiments. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 350.

Major reviews of brood-size manipulation experiments conclude that only juveniles suffer from brood enlargement while parents are unaffected in the majority of studies. However, the most plausible explanation for poor juvenile condition assumes parental costs of increased provisioning. Why is the evidence for cost of reproduction still missing in birds? Only explicit and robust mathematical models of brood-size manipulation can clarify the role and expected level of parental costs. We constructed a series of models on the assumption that provisioning effort is optimised in relation to brood-size. We gave analytical conditions for increased provisioning, number of recruited young, juvenile survival and decreased parental survival with brood-enlargement. We showed that the outcome of an experiment depends to a great extent on whether the original clutch size was below or above the optimal one. Thus, we expect year effects if the birds cannot perfectly optimise their clutch size. Increased number of recruited young, but decreased juvenile survival can be expected if parental survival is a concave, decreasing function of provisioning and clutch size was not larger than the yearly optimum. Based on the models and field data we also made educated guesses on the required sample sizes necessary to show the expected increase in parent mortality. Is there anybody who can enlarge 1000 broods of equal size and keep 1000 as controls? Our major conclusion is that one should look for either indirect evidence or new, more measurable measures of parental costs instead of survival.

Key words: cost of reproduction, individual optimisation, parental care, models, modification approach

1Department of Vertebrate Ecology, Inst. of Ecology PAS, 05-092 Lomianki, Poland, ekolog@warman.com.pl, ²Department of Biology, Kyungnam University, 449 Woelong Dong, Masan 630-701, Republic of Korea; ³Rostov State University, Biol. fac., Engelsa 105, 344711, Rostov on Don, Russia

Pinowski, J. Hahm, K-H., Lebedeva, N., Barkowska, M. & Pinowska, B. 1998. Changes in weight of eggs, the mortality of embryos and development of nestlings of Tree Sparrows Passer montanus. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 352.

The egg weight of successive broods of Tree Sparrows decreases. The weight of eggs increased from the first to the third egg and then decreasing in brood one. In second and third brood, the weight of the egg increased continually from the first to the sixth egg. Unfertilised eggs (the embryos were not visible after the egg was broken) were lighter than those fertilised. However, the mortality of embryos is not related to the weight of the egg. The connection between weight of egg and development of the nestling is still to be analysed.

Key words: Passer montanus, eggs, nestlings, mortality, development

1Department of Biology, University of Turku, FIN-20014 Turku, Finland, e-mail vesa.ruusila@utu.fi, ²Evo Game Research Station, Finnish Game and Fisheries Research Institute, Finland; Jukolantie 1, Fin-71750 Maaninka, Finland

Ruusila, V., Pöysä, H. & Runko, P. 1998. Natal philopatry in a migratory species: Consequences on population structure. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 353.

High natal philopatry in birds is usually documented in species with communal breeding, delayed dispersal and helper-systems. Most studies concern sedentary species, a typical characteristic of philopatric, migratory species breeding in geographically isolated populations. Our study species, the Common Goldeneye Bucephala clangula, differs from this pattern in several aspects. It is a solitary breeding, migratory and geographically dispersed species with delayed maturation. In this study, by using long-term ringing recovery data, we document high female natal philopatry, its consequences for population structure and discuss its costs and benefits. As a result of iteroparous breeding and high breeding site fidelity several family lineages evolve in consecutive generations with most common kinship relations being between mother and daughter and between half-sisters. In most cases, mothers are still breeding in the area when their daughters come to breed there for the first time, suggesting that inheritance of the territory is not behind philopatric behaviour. Contrary, the pattern gives room for local resource competition for nest or brood rearing sites. Benefits of philopatry have to overcome these possible costs to be evolutionarily stable.

Key words: natal philopatry, solitary breeding, migratory, population structure, Bucephala clangula

1Penguin Conference Japan and Universidad Austral de Chile, Valdivia, Chile, e-mail mbernal@uv.cl, ²Universidad de Valparaiso, Via del Mar, Chile

Simeone, A. & Bernal, M. 1998. Seasonal changes in the population size of a Spheniscus humboldti colony in Central Chile. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 353.

Monitoring of substantial Humboldt Penguin Spheniscus humboldti colonies is needed to develop management plans for the conservation of this threatened species. Since 1995 we have been conducting counts every two weeks of roosting and nesting birds at Pajaros Nios colony (33° 21’S, 71° 41’W) in Central Chile. Adult Humboldt Penguins moult from January to March, with the maximum number of birds occurring in late February. After moulting, the birds leave the colony, but a portion of the population returns during April for the autumn breeding peak. During this season, rains collapse many nests and most of adults abandon the colony during winter. By early September, a portion of the adult population returns to the colony for the spring breeding peak, which ends in January. Juvenile penguins arrive at the colony in November and start moulting in early January, with a maximum number of birds occurring in late January. As birds finish moulting in March, they abandon the colony. This survey will allow us to establish a suitable period for conducting population censuses (e.g. moulting season) and determine the effects of oceanographic phenomena like El Nino (ENSO) on population size and breeding success.

Key words: Humboldt Pengiun, population size, Chile

 

1Latvian Ornithological Society, P.O. Box 1010, LV-1050, Riga 50, Latvia, e-mail putni@parks.lv, ²Latvian Ornithological Society, Czech Republic

Strazds, M. & Peske, L. 1998. Postbreeding distribution of the Black Stork in Africa: Gaps in knowledge. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 356.

The Black Stork Ciconia nigra is the stork species with the most extensive range. Its breeding range includes 54 countries and consists of three major sub-populations: European (72%), Asian (18%) and Southern African (10%). European and Asian breeding birds are highly migratory wintering in sub-Saharian Africa and southern Asia respectively. In order to update the world’s status and trends for the Second World Conference on the Black Stork (held in Spain 1996) data were collected from all identified sources both from literature and contacts in each country. The obtained figures show a major gap in the knowledge where the majority of the European breeding population is spending the postbreeding (Palearctic winter) time. Only 10% of the estimated breeding population is reported from Africa, the majority of it from southern Africa. It means that the numbers and distribution of the European Black Storks in the postbreeding season remains largely unknown. The paper presents data supplied from various countries and urges for more intensive co-operation to clarify the distribution pattern of the species.

Key words: Ciconia nigra, winter, distribution, conservation, population

Pacific Adventist University, Private Mail Bag, Boroko, NCD, Papua New Guinea, e-mail tarburton@dg.com.pg

Tarburton, M.K. 1998. Some positive and negative effects of cyclones on the birds of Samoa. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 356.

Tropical cyclones are usually thought of as destructive to birds and possibly totally so in the case of small island populations. Census work on the two main islands of Samoa two to six years after the severe devastation wrought by cyclones Ofa (Feb 1 to 3, 1990) and Val (Dec 6 to 9, 1991) show that no species were lost, but rather three species have colonised the islands as a result of the cyclones. Regular censuses conducted in all ecosystems from mountain rainforests to the barrier reefs, located all land species known to exist prior to the cyclones. Some populations however, suffered drastic declines. Four of 30 colonies of cave-nesting White-rumped Swiftlets were lost while all the rest had been reduced from hundreds or thousands of pairs to between two and 103 pairs. Prior to the cyclones, Crested, Black-naped and Little Terns were rare visitors. The cyclones changed this by braking up large amounts of coral reef which for the first time since European settlement gave Samoa coral islets on the barrier reef. These terns are now breeding on them and are resident.

Key words: swiftlet, echolocation, starvation, waders, coral island, breeding site

Queen's University, Kingston, Ontario, Canada, e-mail friesenv@biology.queensu.ca

Veit, M., Robertson, R. & Friesen, V. 1998. Estimation of gene flow among populations of Cerulean Warbler Dendroica cerulea using molecular methods. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 357.

Cerulean Warblers are songbirds that breed in mature hardwood forest in eastern North America. The species is listed as 'Threatened' since warblers in the main part of their breeding range have poor reproductive success and are declining. However, warblers in Ontario (the northern limit of the breeding range) have high reproductive success. We are using molecular methods to investigate whether warblers breeding in Ontario act as a source of recruits for populations in the United States. Breeding males are caught in mist nets through the use of song playback and model presentation, and females and chicks are caught at their nests. Morphological measurements and a small blood sample are taken from each bird. The mitochondrial control region is amplified via the polymerase chain reaction using general and warbler-specific primers, and variation is assessed using analyses of single-stranded conformational polymorphisms and direct sequencing. Microsatellite loci are amplified using primers previously developed for Yellow Warblers (D. petechia, L. Gibbs, unpubl. data) and screened for length variation. The extent of population differentiation, and the direction and magnitude of gene flow are assessed using standard statistical methods.

Key words: gene flow, source and sink populations, mitochondrial DNA, microsatellites

Centre of Wildlife and Ornithology, ALIGARH Muslim University, Aligarh – 202002, India

Yahya, H.S.A. 1998. Ecology, status and behaviour of Asir Magpie Pica pica asirensis in Asir region of Saudi Arabia. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 357.

The Asir Magpie is an endemic bird of southwest Saudi Arabia whose population and distribution have declined throughout its range. Though morphologically similar to the European or North American races, they have startlingly different calls. A DNA test is being organized to ascertain their race. To determine its present status five reconnaissance surveys were carried out between February 1995 and July 1996 and some isolated populations were recorded at Sooda (n = 5), Bil Ahmar (n = 12), Bil Ismar (n = 26), Tanoma (n = 16) and Jabal Qahar (n = 22) in the Asir region. As many sites as possible were visited where Asir Magpie had been recorded in the past, and an initial assessment of the status of the species in the area was made. They mainly forage in flocks of three, four, five, six, seven and occasionally up to eight. However, breeding pairs keep isolated while feeding nestlings but invariably keep in groups thereafter. The Magpies are restless and are continually moving, calling and foraging throughout the day, from the time they leave the roost site as early as 05h20 until they settle for roosting as late as 19h20. Habitat loss appears to be the main reason for their decline. On account of rapid developments, especially for promoting tourism, the habitat of many birds and animals is shrinking alarmingly throughout and the biodiversity of the Asir Region is at stake. Thus the restoration of habitat is the key factor for the perpetual survival of the Magpie. A long term project to study the ecology and biology of these fast vanishing birds should also be initiated without further delay.

Key words: Pica pica asirensis, endemic, Asir region, status, conservation