L15: Hatching asynchrony, brood reduction, and chick growth in Little Penguins Eudptula minor. Renner, M. & Davis, L.S.

L16: Methodological approach to genetic intra- and inter-specific variability of genus Picumnus. Fulgione, D., Almeida, A.C.C., Caliendo, M.F. & Milone, M.

L17: A contribution to the phylogenesis of Passer with particular considerations to European species..   Milone, M., ,Esposito, A., Rusch, C.E. & Fulgione, D.

Angehr, G. & Robinson, W.D. 1998. Conservation Values of Panama Canal Area Forests. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr. Durban. Ostrich 69: 465.

At the end of 1999, the remaining lands of the Panama Canal Area still under U.S. control will revert to the Republic of Panama. Most of these lands are presently managed by the U.S. Department of Defence (DoD). The Smithsonian Tropical Research Institute, with support from DoD's Legacy Resource management Program, is carrying out surveys directed at documenting the existing bird diversity of these areas and identifying factors influencing this diversity on a regional scale. Important factors in the area include both forest fragmentation and the presence of a very steep rainfall gradient, with a doubling of annual rainfall over the 70 km between the Pacific and Atlantic coasts. Because DoD lands contain several very large blocks of forest, and also include the driest and wettest parts of the rainfall gradient, they are of particular importance for the regional conservation of bird diversity. Much of the area that will revert has been designated for protection by the Republic of Panama after the year 2000, and the information generated by these studies will be used to provide recommendations for future management.

Key words: conservation, Panama Canal, resource management

 

Barluenga, M., Moreno, E. & Barbosa, A. 1998. Tarsus length as a morphological constrain explaining niche shift in the Great Tit. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr. Durban. Ostrich 69: 465.

Two animal species can coexist in an area only if they differ in their ecology. Ecological segregation is not exclusive of between species, but also happens within species. It has been demonstrated that sex differences in habitat use can cause important differences in behaviour, performance and survival of sexes. Two hypotheses have been proposed to explain intraspecific segregation in foraging behaviour: Morphological Hypothesis: morphological differences between individuals can explain their foraging behavioural preferences; Social Dominance Hypothesis: the male and/or adult dominance can explain the spatial segregation of females and/or juveniles. We performed a field study under experimental controlled conditions in a population of Great Tit Parus major. We observed differences in foraging behaviour between sexes, but not between ages. We analysed three morphological characters (body weight, tarsus length and a size factor) and found differences between sexes (males being larger than females) but not between ages. Sexual differences in foraging behaviour disappeared only when the effect of tarsus length was removed. Therefore, in our population it is not needed to invoke social dominance for explaining sexual differences in foraging behaviour.

Key words: tarsus length, morphological hypothesis, social dominance

 

Bleher, B. & Böhning-Gaese, K. 1998. A comparison of seed dispersal by birds in Commiphora spp. between South Africa and Madagascar. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr. Durban. Ostrich 69: 465.

Many plants depend on frugivorous animals for the dispersal of their seeds and its importance for forest regeneration and conservation is well appreciated. The seed dispersal of two related tree species under different dispersal regimes was studied in Commiphora harveyi for South Africa and in C. guillaumini for Madagascar. Tree visitation rates, seed handling and crop removal rates were quantified by observations of eight trees in South Africa and six in Madagascar. Fruit production and dispersal rates were quantified using fruit traps under the same trees. In South Africa, 13 bird species visited the trees with Crowned Hornbills (Tockus alboterminatus) being the main visitors (29.9%) and dispersers (43.1%). In Madagascar, trees were visited by four bird species with Lesser Vasa Parrots (Coracopsis nigra) as main visitors (57.5%) and dispersers (100%). Total dispersal rates in South Africa were considerably higher than in Madagascar (66.3% versus 9.0%, p < 0.0001) which was due to differences in frugivore diversity and handling behavior. Whereas in South Africa most visitors dispersed seeds by swallowing them, in Madagascar dispersal took only place occasionally when parrots left the trees while still handling a seed in their beak

Key words: seed dispersal, frugivore, handling behaviour

 

Briskie, J.V., Martin, P.R., & Martin, T.E. 1998. Nest predation and the evolution of nestling begging calls. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr. Durban. Ostrich 69: 466.

Begging by nestling birds is often conspicuous and loud. Such displays are thought to function in signalling nestling condition and securing parental care, but they also may inadvertently attract the attention of predators. We compared the structure of nestling begging calls to the risk of predation among 24 species of birds breeding in a forest community in central Arizona. After controlling for body size and phylogeny, we found that species subject to greater nest predation had calls with higher frequency (pitch) and lower amplitude (loudness) than species subject to lower rates of nest predation. As these acoustic features make it difficult for potential predators to pinpoint the source of a sound, our results suggest that an increased risk of predation has lead to the evolution of begging calls that minimise locatability. The relationship between call structure and the risk of predation also supports the hypothesis that attracting predators is a direct cost to begging and that such costs can dampen any evolutionary escalation in the intensity of begging.

Key words: nest predation, nestling vocalisations, begging behaviour, Arizona

 

Calmaestra, R.G. & Moreno, E. 1998. Ecomorphological patterns related to migration: a myological study with passerines. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr. Durban. Ostrich 69: 466.

Within passerines it has been stated that migrant species differed from resident forms by possessing bigger pectoral muscles and less developed minor flight muscles. We have tested this statement by comparing forelimb muscles (M. pectoralis, M. supracoracoideus, M. deltoideus major, M. scapulotriceps, M. humerotriceps and M. biceps brachii) in 10 passerines genera. Each genus was represented by a pair of species one being sedentary and another migratory. Using a phylogenetically based method of comparison we found that only the pectoralis muscle is more developed in migratory species than in their sedentary counterpart, M. supracoracoideus not differing between both groups of species. This result can be explained on the light of the different functional meaning of both muscles. The pectoralis muscle, the main wing depressor, is likely adaptively modified in migratory species for increasing the force it is able to develop upon contraction to counteract the upward action of airflow, mostly during fast flight. M. supracoracoideus, the main wing elevator, may not be active in fast flight but only at slow flight and take-off. We also found no differences between sedentary and migratory species in minor flight muscles, suggesting that these muscles do not contribute much to active fast flight.

Key words: muscles, migration, phylogenetics

 

Jarvis, A.M. & Robertson, A. 1998. Predicting population sizes and priority conservation areas for 10 endemic Namibian bird species. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr. Durban. Ostrich 69: 467.

Namibia’s avifauna includes at least 14 species currently classified as national endemics or near-endemics. For most of these, information required for effective conservation planning and management is lacking or inadequate. This study assessed population size, status and distribution of 10 of these species. Line transect sampling was undertaken over 7 months in 1996. For all species, significant regression relationships were obtained between calculated bird density and environmental variables (altitude, rainfall and vegetation type), and these relationships were used to predict bird abundance in each extant combination of environmental variables. A GIS was used to map predicted abundances, calculate population sizes and define species’ distribution limits. Predicted population sizes ranged between 1 848 and 1 501 029 birds, representing the first population estimates for southern African birds using this approach. For all species, total population size appears to be viable but protected areas exclude their core areas and may not support viable populations. A modified Shannon index was calculated to determine areas of highest diversity. Most diversity hotspots fall within the Escarpment vegetation zone, very little of which is formally protected. We emphasise the conservation importance of this zone for Namibia’s endemic birds.

Key words: Namibia, endemics, , GIS, biodiversity

 

Linden, H. & Pienmunne, E. 1998. Non-stable age distributions of cyclic Capercaillie Tetrao urogallus populations in Finland. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr. Durban. Ostrich 69: 467.

We studied th7.e variation in age structure in Capercaillie during population cycles in Finland. More than 2000 skulls were collected from hunters for age determination, which was based on several ossification criteria. There is evidence that one-year-old females are poor breeders and that the oldest females reproduce most successfully. We observed marked changes in the age structure of the adult population in different phases of population cycles. The patterns were different for the sexes owing probably to the difference in longevity between them. Age structure, expressed as the average age of the female population, accounted for a half of the annual variation in the number of juveniles per adult female in August. We argue that the population age structure is an important, but rarely documented, factor associated with Capercaillie population cycles.

Key words: demography, experience, age structure, Western Capercaillie

 

Tidemann, S.C., Bradley, J., Kofod, F., Rogers, C. & Wright, S. 1998. Inter-relationships between birds and people: an Australian indigenous perspective. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr. Durban. Ostrich 69: 467.

There is a richness about indigenous ecology that is lacking in mainstream ecological studies. For years, stories and songs have been handed down. Sometimes 'mainstream-trained' ecologists fail to recognise the wealth of knowledge held by indigenous people. To indigeous Australians, birds are related to: (1) Food, e.g., around Ngukurr, when Australian Pelicans (Balmi) are found in groups, billabongs are ready to be poisoned using pounded bark from freshwater mangroves to obtain the fish; short calls of a Pied Butcherbird (Gurrugi), while it dances, tell that a kangaroo is around; once Red-tailed Black-Cockatoos (Ngadurru) finish feeding on the fruits of a particular eucalypt, the wild honey is nearly ready to harvest, while the calls of the Common Koel (Dowoo-Dowoo) tell that green plums (Terminalia sp.) are ripe. (2) Social relationships, e.g., at any time of the year, in the Ngukurr region, a single Brolga (Gurdarrgu) flying around and calling forecasts family squabbles in the community; the long sweet calls of the Pied Butcherbird (Gurrugi) tell of friends or family coming to visit, while its long sorrowful calls mean that a family member has died. (3) Spiritual matters, e.g., in the Ngukurr region, Willie Wagtail (Ginnirrginnigidi) calls mean that bad spirits are around or that one is near an old burial site in a cave or the fork of a big tree. (4) Ceremonies, that have songs about birds linked integrally with them, e.g., in the Borroloola area, a group of Yanyuwa people perform songs about seed eaters at circumcision rituals; and the behaviour of Brolgas is captured in a song performed at funeral ceremonies. Because of the age of the stories, they can represent pictures of former landscapes and the presence of species that scientists think are newly discovered or extinct. Ecological studies in Australia would be the richer for the incorporation of indigenous knowledge.

Key words: indigenous perspectives.

 

Simmons, R.E. 1998. The Skutch clutch dilemma: Nourishable young and predation in the tropics - a solution. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr. Durban. Ostrich 69: 468.

In 1947 Lack proposed that clutch size was determined by the number of young parents could adequately nourish. Alexander Skutch disagreed: I suggest that neotropical passerines were not food-limited because: (1) Two-parent species reared as many young as single-parent species. (2) Host species frequently raised a brood parasite larger than their own young. (3) On adding young to nests, parents reared the extra young. Instead high predation levels may select for the small clutch since small broods reduce the number of nest visits, nestling noise and duration in the nest, potentially reducing predation. Recent brood addition experiments for two subtropical species, however, show no increase in predation for enlarged broods, suggesting predation is not limiting brood size. The Skutch clutch dilemma is therefore: if parents can nourish more young than they typically rear, and predation does not limit clutch size, what is limiting clutch size in tropical regions? The problem has been clouded by the level of measurement because single clutches are an inappropriate measure of seasonal output for tropical species which lay two or more clutches in an extended seasonal environment. A second key factor is provided by a summary of food supplementation experiments. Double-brooded species do not lay larger clutches when food supplemented (92% of 12 species), while single-brooded species do lay larger clutches (75% of 12 species), a significant difference (p < 0.005). Single brooders have no option to lay a second clutch so put increased energy into more eggs. Double brooders put the increased energy into more broods. Thus a new two-basket hypothesis proposes that tropical species lay small clutches because they can then lay a second (and third) clutch which enhances their fitness more than increasing their clutch size. An extended season with low resources, not increased predation, selects for small clutches in tropical areas.

Key words: clutch size, bet-hedging, life-history strategies, breeding

 

Goddard, K., Lawes, M.J., Slotow, R., & Andersson, S. 1998. Correlates of reproductive success in the colonially breeding polygynous Red Bishop Euplectes orix. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr. Durban. Ostrich 69 Addendum: 5.

Sexual selection through female choice is traditionally invoked to explain the evolution of elaborate male features or behaviours, often without empirical evidence to support this supposition. This is primarily because of the difficulties in identifying cues used in female choice. We examined the correlates of male reproductive success in the sexually dimorphic, polygynous red bishop using multivariate techniques in order to: (1) empirically ascertain whether female choice occurs, (2) identify cues used by females to distinguish between males, and (3) to provide some insight into why red bishops are colonial breeders. We found that the only correlate of male success is the number of nests built by territory males. Male morphology shows insufficient variation for females to reliably discriminate among males, and male display behaviour does not influence reproductive success. In addition, we show that female settlement patterns are not significantly different from that predicted for random settlement. We argue that, despite the conspicuous dimorphism, females settle independently of either male or territory quality, and that variance in male reproductive success is a consequence of male-male competition.

Key words: sexual selection, female choice, Ploceidae, Africa

 

Dodman, T., Sylla, I. & Ndiaye, A. 1998. Implementing a preliminary waterbird monitoring strategy for Africa. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69 Addendum: 6.

A preliminary waterbird monitoring strategy for Africa was recently published (Dodman, 1997) as a result of an extensive continent-wide review process, an international workshop and some basic analyses of data held in the African Waterfowl Census (AfWC) database. The strategy presents key issues to help the practical development of more definitive and specific action plans, especially at the sub-regional, species and site levels. Particular emphases are given to maximising the practical use of AfWC data for conservation purposes, developing the capacities of participating organisations and involving local communities. This strategy is now being implemented in West Africa through field training courses, e.g. in Burkina Faso, Niger and The Gambia, surveys, e.g. of coastal sites in Mauritania and Cameroon and of colonial Laridae in Senegalís Saloum Delta, and the exchange of personnel within the sub-region. A sub-regional training programme and network development provide further support, whilst a committee monitors progress and guides development of a wetland monitoring strategy for West Africa. At the international level, data uses include the identification of shadow Ramsar Sites and 300 potential Important Bird Areas (IBAs) for Africa and the support of the Agreement on the Conservation of African-Eurasian Migratory Waterbirds. Thus, mechanisms are being established for enabling biological data - and the process of obtaining this data ñ to contribute to conservation action, awareness and site and species management.

Key words: African, waterfowl, census, training, data

 

Kunz, C. 1998. Blue Tit nestlings trade body growth for health. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr.. Durban, University of Natal. Ostrich 69 Addendum: 6.

In asynchronously hatched broods, last-hatched nestlings often receive less food than their older siblings. How do last-hatched nestlings allocate their limited resources between different demanding traits, such as body growth and health? I investigated this problem in an experimental study on Blue Tit Parus caeruleus nestlings. I created a size hierarchy among nestlings by swopping young among broods differing in hatching date by two days. Swopping was done on day 4 posthatch of the older brood. I found that the smallest nestlings within the size hierarchy preferentially allocated their limited resources into wing growth and fat reserves, at the cost of health status. This strategy may enhance short-term survival, but can imply fitness costs in a longer perspective.

Key words: Parus caeruleus, asynchronous hatching, resource allocation

 

Woldemariam, T., Edwards, S. & Teketay, D. 1998. Diversity of avifauna in a dry Afromontane forest on the central plateau of Ethiopia. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69 Addendum: 7.

Bird species diversity of Chilimo Forest was studied to evaluate its importance for conservation of biodiversity, taking birds as indicators. A point-transect method with a fixed radius (radius = 25 m) was used. Two counting periods, five and eight minutes, were used to record bird data. A total of 60 points was surveyed. Bird species seen outside of the study points anywhere in the forest area were also recorded. Results showed 114 bird species occur in the area. Out of the total checklist, 63 bird species were encountered at the study points. Among the bird communities, 32 Afrotropical highland biome (HB), three endemic and nine near-endemic species were recorded. The five most abundant species were HB species. The distribution of bird species communities follows the log-series. There was no significant difference between the two counting periods in bird species diversity. Chilimo resembled Menagesha but was much richer in bird species composition . Chilimo qualifies as an important site for conservation of HB, harbouring 67% of the total biome species occurring in the country, based on Important Bird Areas (IBAs) selection criteria.

Key words: diversity, dry Afromontane forest, Afrotropical highland biome bird species, Important Bird Areas.

 

Romdal, T. S. & Dinesen, L. 1998. Source and sink habitat of forest birds in Tanzania and implications for conservation. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69 Addendum: 7.

Forest birds with broad altitudinal ranges may be lost from mountains with only partial forest cover, because the productive part of the range (source habitat) vanishes and only a non-viable population (in sink habitat) remains. Relative abundance of all forest birds on the altitudinal gradient in the Eastern Arc of Tanzania was established in two different mountain ranges with fully forested gradients. The method was simple registrations of all individuals encountered. Source and sink habitats with relation to altitude were detected from the abundance figures and assumed to be general for each species. Analysis of species distributions in nine Eastern Arc mountain ranges shows that species are likely to be missing from mountains where only sink habitat is available. For submontane species, the hypothesis is confirmed in 75% of the cases. Two important conservation implications appear: 1) As the mountain forest becomes degraded from below, species with source habitat at low altitude will disappear rapidly, although they may occur on the entire altitudinal gradient. 2) Generally, if the range of any endangered species can be divided into source and sink habitat, it is crucial to protect the source habitat.

Department of Zoology,University of Otago, P O Box 56, Dunedin, New Zealand, martinr@hrz.uni-bielefeld.de

Renner, M. & Davis, L.S. 1998. Hatching asynchrony, brood reduction, and chick growth in Little Penguins Eudptula minor. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr.. Durban, University of Natal. Ostrich 69 Addendum: 8.

We studied the effect of hatching asynchrony on brood reduction and growth in Little Penguins Eudptula minor over two years. Breeding success was low in both years, most likely due to food shortage. Survival of single chicks was not higher than that of A-chicks, but A-chicks were more likely to survive than B-chicks. The risk of brood reduction was greatest during the middle of the guard and lowest during the post-guard stage. Hatching asynchrony had a significant effect on brood reduction: every further day almost doubled the B-chick's chances of dying before A-chick. Growth parameters (fledgling size/mass, maximal growth rate, and age of maximal growth) did not differ between A-and B-chicks. Single chicks, however, reached a significantly greater fledgling mass. In A-chicks that lost a sibling fledgling mass was negatively related to the age when the sibling died. Adult quality (measured by the length of foraging trips during incubation and egg volume) had no significant effect on chick survival, hatching asynchrony, or brood size. A prediction of first year survival based on fledgling mass suggests that the A-chick's increased survival is not likely to compensate for the loss of B-chick. Therefore, the Lack hypothesis is unlikely to be valid for Little Penguins, even when extended by post fledgling survival.

 

1Dipartimento di Zoologia, Universita' Federico 11, Napoli, via Mezzocannone 8, 80046 Italia, e mail milone@unina.it; ²Bloco G1/103, Rua J.C. Sobrinho, Mangaberia VII, 58058-140, Joao Pesoa (PB), Brazil

Fulgione, D., Almeida, A.C.C., Caliendo, M.F. & Milone, M. 1999. Methodological approach to genetic intra- and inter-specific variability of genus Picumnus. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban: 3230. Johannesburg: BirdLife South Africa.

Picumnus sp. Represents some of less-known birds lives in the Amazon Rain forest. Until now these species are described according to their plumage and morphometry. The aim of our poster is to contribute to clarify conservation objectives utilising genetic techniques. Birds were collected in heart forest and forest edge in seven sites (Gios, Bahia, Ceara, Alagos, Amazonia, Paraiba, Minas Gerias). The birds were classified according to their morphology and plumage traits as P. fulvescens, P. limae, P. exilis, P. guttifer, P. pygmaeus. Liver was used for biomolecular assays. We have performed a DNA characterisation based on R.A.P.D. using four primers (C5, C6, C7, C9). The methodology seems to be able to discriminate the diversity within and between taxa considered. P. limae and P. fulvescens show two distinguished genetic pattern according to the 'good species' collocation. Other taxa are according to the clinal genetic variation.

Dipartimento di Zoologia, Universita' Federico 11, Napoli, via Mezzocannone 8, 80046 Italia, e mail milone@unina.it

Milone, M., Esposito, A., Rusch, C.E. & Fulgione, D. 1999. A contribution to the phylogenesis of Passer with particular considerations to European species. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban: 3230. Johannesburg: BirdLife South Africa.

In this contribution we expose first results of genetic approaches based on restriction fragment analysis of nuclear non-coding DNA of five sparrow species. Passer ammodendri, P. domesticus, P. griseus, P. hispaniolensis, P. italiae. Biomolecular analysis were carried out using tissues and/ or blood samples. Genomic DNA were digested with Hae III; hybridisation was performed utilising two probes. The first, for intraspecific analysis, was obtained digesting M13 phage with CIa I enzyme. The second, principally for intraspecific analysis, was obtained by PCR amplification of specific box of M13 phage, interposed between 1013 and 2528 base position. P. italiae and P. hispaniolensis are close and linked to P. griseus also. P. domesticus is disjointed from these species by P. ammodendri. The Italian populations (13) show clinal variations along the peninsula; P. domesticus and Alpine populations differ substantially from the others, P. hispaniolensis minisatellite profile reveals high similarity to all peninsular populations.