Showing papers in "Journal of Ornithology in 2004"

Avian mitochondrial DNA sequence divergence across a headwater stream of the Rio Tapajós, a major Amazonian river

Abstract: Populations of ten Amazonian bird species were sampled on opposite banks of the Rio Teles Pires, a headwater stream of the Rio Tapajos, in the Alta Floresta region, northern Mato Grosso, Brazil. The river is 100–300 m wide in this region. We found a range of genetic differentiation from none to relatively high levels; six of the ten species studied exhibit what appear to be genetic breaks at the river. With one exception, the antbird Hylophylax poecilinota, there is no morphologically recognized differentiation correlating with genetic differentiation. From the perspective of traditional morphology-based taxonomy, the Rio Teles Pires is not a faunal barrier. Rather, contact zones between members of species and subspecies pairs appear more or less randomly distributed in this region, some being located at varying distances to the east, others at varying distances to the west of the Rio Teles Pires, with few following the course of this river itself.

Diversity of the Białowieża Forest avifauna in space and time

Abstract: The Bialowieza Forest (BF) is an extensive and relatively little changed forest complex on the Polish-Belarussian border. Data on the structure and diversity of its breeding avifauna have mostly been collected in primeval old-growth stands, preserved within the Bialowieza National Park (BNP). Mapping censuses repeated in space (plots, replicated in riverine, oak-lime-hornbeam and coniferous stands) and time (permanent plots, 28 years) reveal that the breeding bird assemblages are rich in species (29–52/season in a 25 to 33-ha plot), but of moderate overall density (40–120 pairs/10 ha). The latter is due to low, lower than in man-transformed areas, densities of the majority of particular species. Despite marked changes in vegetation structure, the composition of the breeding bird assemblage does not vary much across different primeval forest types, with a single breeding bird community inhabiting all of them, including treefall gaps. High richness of the BF avifauna stems from the Forest’s geographical locality, as well as from a high level of the primeval avifauna retention. Over 95% of the 135–140 pristine species still breed there. Especially species-rich groups are birds of prey, owls, woodpeckers and Sylvinae warblers. Bird communities in the BNP and primeval tropical rain forests share many features, suggesting that natural differences between temperate and tropical forests were less pronounced in the past. The combination of high species richness with low densities of individual species is probably a feature of all pristine forests, independent of climatic zone. The BF avifauna must once have been typical of the ancient European forests and it has become so exceptional chiefly because it has preserved most of its pristine features. The BF thus constitutes an indispensable reference site for future studies of woodland bird biology. To ensure its survival should become a priority. Commercial logging, taking place over 80% of the Polish BF part, severely changes the Forest’s structure and strongly affects the birds, especially species which depend on dead wood (Dendrocopos leucotos, Picoides tridactylus) and on old-growth stands. The small area protected as the BNP becomes an increasingly isolated “island”, in which preservation of the primeval forest features seems to be impossible. In order to retain them, it is necessary to protect the whole BF area.

Ecological constraints on the evolution of avian brains

Abstract: Birds have brains that are comparable in size to those of mammals. However, variation in relative avian brain size is greater in birds. Thus, birds are ideal subjects for comparative studies on the ecological and behavioral influences on the evolution of the brain and its components. Previous studies of ecological or behavioral correlates in relative brain size were mainly based on gross comparisons between higher taxa or focussed on the relationships between the sizes of specific brain structures and the complexity of different tasks. Here we examine variation in dimensions of the braincase, relative overall brain size and size of its components, in reference to one general ecological and behavioral task: migration. We used data from three lineages of closely related species (14 Acrocephalines, 17 Sylvia and 49 parulid warblers). Within each group, species vary in their migratory tendencies. We found that species migrating long distances have lower skulls and smaller forebrains than resident species. We discuss four hypotheses that could explain smaller forebrain sizes, and suggest relevant taxa to use in comparative analyses to examine each of these hypotheses: We also raise the question of whether only those parts of the brain are reduced that are most dispensable and whether brain size reduction limits foraging skills and social competence.

Long-term satellite tracking of white stork ( Ciconia ciconia ) migration: constancy versus variability

Abstract: During satellite-tracking investigations of 140 white storks (Ciconia ciconia), one individual, the long-term world record holder among birds, was followed along 12 migratory journeys over a period of 10 years. This long-term study confirms what previous several-year tracking studies of white storks had indicated: there can be great variability from year to year in the choice of winter quarters as well as in the routes and times of migration, intermediate destinations and stop-over periods, but constancy of winter quarters and migration routes is also possible. The variability may well be caused by external factors, of which food supply is probably predominant.

Nest site selection and nesting success of five species of passerines in a South American open Prosopis woodland

Abstract: I analyzed nest site preferences and whether these preferences were linked to nest success of five bird species breeding in an arid area of southern South America. Most nests (90%) were located in three plant species (Geoffroea decorticans, Capparis atamisquea, and Atriplex lampa). Serpophaga griseiceps, Poospiza ornata, and P. torquata nested in plants with size significantly different from randomly selected plants. At the mesohabitat scale (i.e., habitat patch surrounding the nest), four species showed clear differences from random patches within the general habitat, and the remaining species (Saltatricula multicolor) showed a non-significant trend. The daily survival rate of S. griseiceps nests placed in the preferred plant species (i.e., G. decorticans) was lower than those in the other nest-plants. In the other four bird species, nest survival did not differ between preferred and other plants used for nesting. At the scale of microhabitat (i.e., plant size and location of the nest inside the plant), no significant differences were detected between unsuccessful and successful nests. Similarly, unsuccessful nest patches did not differ significantly in habitat features from those that were successful. High nest predation rates found in this habitat (around 85% for the total assemblage) and a relatively high diversity of predators (and of predation tactics) appear to impede the presence of “safe” sites for nesting (i.e., there are trade-offs between avoidance strategies).

Migrations and sojourn in Africa of Egyptian vultures (Neophron percnopterus) tracked by satellite

Abstract: By means of satellite telemetry, the migrations of three young Egyptian vultures (Neophron percnopterus) from France and Bulgaria were studied and data obtained (over 4,300 Argos locations) to describe movement patterns, timing of migration, routes followed, speed of flight and ranging behaviour in Africa. Two French vultures migrated at almost the same time and, after travelling ca. 3,570 km, remained in the Sahelian zone, in southern Mauritania. The Bulgarian bird, after travelling 5,340 km, ended in south-east Chad, in the Sudano-Sahelian zone. It was possible to determine two remarkably long daily flight distances of this bird of over 500 km on two successive days (1,017 km in total) when crossing the Sahara. In January and February, the Bulgarian bird wandered extensively over 2,600 km, even as far as north-east Nigeria. Both French vultures remained in their home ranges in Mauritania once they had adopted them, which extended to 69,000 km2 and 50,000 km2, respectively. One continuously-tracked vulture from France first left its African home range when 3 years old (probably in its fourth plumage type).

Radiation and species limits in the Asian Pallas’s warbler complex ( Phylloscopus proregulus s.l.)*

Abstract: Pallas’s Warbler (Phylloscopus proregulus) of the Eastern Palaearctic (Siberia, China, Himalayas) resolves into a complex of four closely related but distinct allospecies forming a superspecies, P. [proregulus]. Assignment of species rank is based on cytochrome-b gene sequences and on vocalisations (territorial song and calls). Morphological divergence is poor, as is typical in Phylloscopus. It applies to size (nominate Siberian proregulus as opposed to the Sino-Himalayan taxa), and slight coloration differences among the latter taxa do not correspond to the cyt-b topology and are considered to be adaptive. Vocal differences relate to syntax (verse song vs endless song), frequency (broad vs narrow bandwidth, allocation of elements within the frequency band), form of elements (ascending vs descending parts, combination of these), and repertoire size. Strong premating isolating mechanisms are assigned to vocalisations. Contrary to current taxonomy, we propose the following constituent taxa of the Phylloscopus [proregulus] complex: Phylloscopus proregulus s.str. (Siberia, disjunct from the following taxa), P. kansuensis (China: Gansu, Qinghai), P. forresti (W/SW China, part of E Himalayas?), P. chloronotus with two subspecies: P. c. simlaensis (W Himalayas), and P. c. chloronotus (C and E Himalayas). Contact zones and possible hybridisation between the Sino-Himalayan taxa remain undetermined. A closely related isospecies is Phylloscopus yunnanensis (syn. P. sichuanensis), which is locally sympatric with and extremely similar morphologically to P. forresti and P. kansuensis. Cyt-b distance values range from 3.1% to 4.6% within the P. proregulus complex and from 7.5% to 8.4% between the latter and P. yunnanensis. This corresponds to differentiation times of 4.1 to 5.5 Myears (P. proregulus complex vs P. yunnanensis) and 1.7 to 3.2 Myears (within the P. proregulus complex).

Migration, wintering and breeding of a lesser spotted eagle ( Aquila pomarina ) from Slovakia tracked by satellite

Abstract: In northern Slovakia an adult male Lesser Spotted Eagle (Aquila pomarina) occupied the same nest site for 11 years running (1992–2002), where it was ringed and fitted with two satellite transmitters. In six of these years it successfully reared a young. In 1994 and 2000–2002 its behaviour during migration could be followed in detail by means of satellite telemetry. The eagle took the known route for this species to South Africa. In 2001, it spent 43% of the year at its breeding site, 33% in its winter quarters, the remaining 24% being spent on migration. In three cases the autumn migration took 40, 48 and 61 days respectively. In two cases the spring migration took 49 days. All five recorded autumn and spring migrations averaged a daily flight distance of 178 km. In spring the daily flight distance was in general slightly greater than in autumn. The longest was recorded from 30 March to 2 April 2001, between Uganda and the Red Sea, during which the bird covered a total of 1,650 km, averaging 412 km per day. In 2001, the spring migration from the wintering grounds was 2 weeks later than in 2002. The wintering grounds, where in 2 years the bird spent around 3.5 months, covering at least 1,666 and 2,269 km, respectively, comprised a large part of Zimbabwe together with the Kruger National Park in South Africa and neighbouring parts of Mozambique. The annual journeys flown, including movements around the wintering grounds, amounted in 2000-2001 to at least 20,396 km and in 2001-2002 to 19,041 km. Except during its crossing of the Sahara, the eagle must have taken food on nearly all its days of migration.

A partial skeleton of a new fossil loon (Aves, Gaviiformes) from the early Oligocene of Germany with preserved stomach content

Abstract: A partial skeleton of a new fossil loon (Aves, Gaviiformes), ?Colymboides metzleri n.sp., is described from the early Oligocene (Rupelian) of Frauenweiler in Germany. The new species resembles the early Miocene species Colymboides minutus in size and overall morphology, but differs in several osteological details. The specimen represents the first associated remains of an early Tertiary loon. Preserved stomach content further provides the first direct evidence that early Tertiary loons were already specialized towards a piscivorous diet, hunting fishes in a marine environment.

Experiments with artificial nests on predation in reed habitats

Abstract: We performed nest predation experiments with artificial nests in reedbeds investigating whether nest predation pressure is different at the water-reed edge and the grassland-reed edge compared with the reed interior. Furthermore, we tested the effects of vegetation structure (reed density, height and thickness) and the effect of other nest site characteristics (distance from edge, water depth) on the success of artificial nests. The experiments were completed 3 times during the breeding season in 2001 at Lake Neusiedl, Austria. Each artificial nest resembled Great Reed Warbler (Acrocephalus arundinaceus) nests and contained one plasticine and one Quail (Coturnix coturnix) egg and the predators were identified by marks left on the eggs. The potential predators were birds, probably the Marsh Harrier (Circus aeruginosus), gulls (Larus spp.) and reed warblers (Acrocephalus spp.). Nest survival data were analysed using the Mayfield method, and we performed a discriminant analysis for the data of vegetation and nest site characteristics. The nest predation was higher at the edges than in the reed interior, and was most pronounced in April, before the new reed sprouted. The reason for this finding was probably that after May the new reed contributed to greater concealment of the nests through the higher reed density and height.

Frequency of bird hybrids: does detectability make all the difference?

Abstract: The number of hybrids recorded in the field may be biased because these data may simply reflect the detectability of a hybrid pairing A questionnaire was constructed for assessing the detectability of natural avian hybrids Ratings from 17 independent experienced observers were subjected to factor analysis and all observers loaded onto the same single factor The reliability was extremely high (Cronbach’s alpha=096) Initially, I found a weak positive and significant correlation between the number of hybrids and their detectability index (r s=0268; P=0015; n=81) However, the respective correlations within three orders and one family containing enough hybrids for analysis revealed non-significant results Significant differences existed among orders with respect to both detectability and hybrid frequency At the family level, differences existed in detectability, but not in the number of hybrids recorded Furthermore, I found no publication bias These results suggest a general influence of detectability and on higher taxonomic levels, and that either detectability or the number of hybrids vary between orders possibly due to phylogenetic effects Data about hybrids should be used in a cautious manner in analyses across a wide range of species, but seem unbiased when restricted to analyses within orders and families As a rule of thumb, distinctness of hybrids seems to be a function of the plumage difference between the hybridising species

Individual changes underlie age-specific pattern of laying date and egg-size in female common terns Sterna hirundo

Abstract: It has been suggested that breeding performance differs between young and old birds due to the appearance and disappearance of phenotypes through differential survival (selection hypothesis) or differential recruitment (delayed breeding hypothesis) of high-quality individuals, but each bird may show constant breeding performance over its life. We tested constant egg-volume and laying date by modelling their variability on the basis of the 109 known-age females of common tern Sterna hirundo with data available from 1 to 9 years. Longitudinal analyses showed a significant advancement of laying date, as well as a steady increase in egg-volume, in young age classes from 2 to 5–7 years old, indicating individual intrinsic changes in performance with age. In our model, female effect accounted for 74% and 8% of variance in egg-volume and laying date, respectively, suggesting that if correlation between breeding performance and survival or recruitment exists, population patterns of age-specific performance may emerge. However, we found no evidence that birds that did not return to breed during young age classes laid later or smaller eggs than returned breeders. Likewise, we found no evidence that recruiting birds laid earlier or larger eggs than same aged birds recruited in preceding years. Thus, this study shows that age-specific patterns in timing of breeding and egg-size in common terns result from individuals’ intrinsic changes, and we reject the selection and the delayed breeding hypotheses as a major factor shaping age-specific patterns at population level.

Magellanic woodpecker ( Campephilus magellanicus ) abundance and foraging in Tierra del Fuego, Chile

Abstract: The Magellanic woodpecker (Campephilus magellanicus) is a vulnerable and poorly studied bird in the sub-antarctic deciduous and evergreen beech (Nothofagus) forests of South America. On Tierra del Fuego island (Chile), we compared Magellanic woodpecker abundance and its foraging habitat in two forest types: pure N. pumilio and mixed forests composed by N. pumilio and N. betuloides, including managed and non managed stands. At a regional scale, abundance of woodpeckers was greater in landscapes including both forest types than in pure N. pumilio landscapes. When both forest types occurred together, woodpecker abundance did not differ between them. The number of trees with foraging signs was correlated with Magellanic woodpecker abundance and was also associated with N. betuloides and snag densities, but was not affected by forest management. Occurrence of pecking on foraging trees was greater in mixed Nothofagus than pure N. pumilio stands. Woodpeckers foraged disproportionately more on larger diameter and more decayed trees. Moreover, trees used for foraging were positively correlated with canopy cover and snag density and were negatively correlated with distance to nearby peatlands and beaver ponds. Direct observation revealed that the flying distance between trees was negatively correlated with proportion of trees with foraging signs. Woodpeckers chose trees that were visited before, suggesting a pattern of tree recognition within foraging territories.

Moult of three Palaearctic migrants in their West African winter quarters

Abstract: Some theories about moult strategies of Palaearctic passerine migrants assume that birds adapt timing of moult to environmental conditions such as rainfall on their African wintering grounds. Species wintering in the northern tropics should limit moult to the period shortly after their arrival at the end of the rainy season. Passerine migrants wintering in West Africa should also moult more rapidly compared to related species or conspecific populations that moult elsewhere. We investigated the moult of melodious warblers Hippolais polyglotta, willow warblers Phylloscopus trochilus and pied flycatchers Ficedula hypoleuca wintering in Comoe National Park, Ivory Coast, between October 1994 and April 1998. In contrast to previous studies we did not restrict our analyses to moult of flight feathers but also included moult of body feathers. The results differed partially from the general assumptions of previous authors. Melodious warblers moulted twice: a complete moult shortly after their arrival, and a moult of body feathers and in some cases some tertials and secondaries in spring. Willow warblers moulting flight feathers were found between December and March with the majority moulting in January and February. Primary moult was not faster compared to populations moulting in central Africa and South Africa. Body feather moult varied strongly among individuals with birds in heavy moult between December and April. Pied flycatchers moulted body feathers and tertials between January and April. Birds with growing feathers were found throughout the whole period including the entire dry season. Moult strategies are thus not readily related to a few environmental factors in general and our results show that factors other than mere resource availability during certain times on the wintering grounds are likely to govern the timing of moult.

Should avian egg size increase as a result of global warming? A case study using the red-backed shrike (Lanius collurio)

Abstract: From some life-history traits, avian egg size can be postulated as potentially affected by climate change. In this paper, we present and discuss the potential effect of mean temperature in the breeding season on egg size of the red-backed shrike (Lanius collurio). During the 1971–2002 study period, egg volume of the red-backed shrike decreased significantly, birds arrived at the breeding site significantly earlier, and arrival date was correlated with the earliest first egg date. To our knowledge, we present the first evidence that avian egg size decreased significantly in a long-term study. However, we do not have experimental manipulations in support of our data and we can only conclude that the decrease in egg volume in the studied population might result as a consequence of a number of factors, including changes in temperature, as well as in food supply. Therefore climate change effects on a bird’s life-history traits can be more complex than just the simple direct effect of temperature.

Migrating swans profit from favourable changes in wind conditions at low altitude

Abstract: Because energy reserves limit flight range, wind assistance may be of crucial importance for migratory birds. We tracked eight Bewick’s swans Cygnus columbianus bewickii, using 95-g satellite transmitters with altimeters and activity sensors, during their spring migration from Denmark to northern Russia in 1996. During the 82 occasions where a swan’s location was recorded in flight, average flight altitude was 165 m a.s.l. with a maximum of 759 m a.s.l., despite winds often being more favourable at higher altitudes. We also counted Bewick’s swans departing from the Gulf of Finland and subsequently passing an observatory in the next major stop-over area 800 km further north in the White Sea, northern Russia, during the springs of 1994, 1995 and 1996. A comparison of these counts with wind data provided evidence for Bewick’s swans using favourable changes in wind conditions to embark on migration. Changes in the numbers of birds arriving in the White Sea correlated best with favourable changes in winds in the Gulf of Finland 1 day earlier. Again, migratory volume showed a correlation with winds at low altitudes only, despite wind conditions for the swans being more favourable at high altitudes. We conclude that the relatively large Bewick’s swan tends to gear its migration to wind conditions at low altitude only. We argue that Bewick’s swans do not climb to high altitudes because of mechanical and physiological limitations with respect to the generation of power for flight and to avoid rapid dehydration.

Blood values of Bald Ibis (Geronticus eremita) in captivity: comparative ranges and variability with age, sex and physical condition

Abstract: The Bald Ibis (Geronticus eremita) is one of the world’s most threatened species of birds. The number of individuals in captivity is several times greater than the number of individuals in the wild, so that the re-introduction of individuals from captive breeding into their natural habitat may be vital for the recovery of the species. A knowledge of the health problems associated with the handling of captive individuals and the improvement of their veterinary care could have great importance in determining the success of these captive breeding programs. Haematology and blood chemistry are very useful complementary tools in the diagnosis and treatment of diseases in birds, and provide valuable information about the individual’s nutritional status and physical condition. The present work reports haematocrit and blood chemistry values for individuals belonging to a captive population of this species, and analyses their variability with respect to age, sex, and physical condition of the animals. Adults presented greater values of haematocrit, uric acid, total proteins, cholesterol, and aspartate amine transferase than the young. With respect to sex differences, adult female birds had higher concentrations of alkaline phosphatase than males, contrary to previous results for captive individuals of this species. The condition index of adults was positively correlated with triglycerides, glucose, and alkaline phosphatase levels, and negatively with urea and lactate dehydrogenase levels. These results may be very useful as a complementary diagnosis tool during the veterinary care of individuals of this species included in re-introduction programs.

The phylogenetic relationships of the early Tertiary Primoscenidae and Sylphornithidae and the sister taxon of crown group piciform birds

Abstract: The phylogenetic relationships of the early Tertiary Primoscenidae and Sylphornithidae are, for the first time, evaluated in a cladistic context. Both taxa include small arboreal birds with a permanently (Primoscenidae) or facultatively (Sylphornithidae) retroverted fourth toe. Primoscenidae were hitherto considered to be most closely related to either woodpeckers and allies (Piciformes) or to songbirds (Passeriformes), whereas the Sylphornithidae were classified into the roller-kingfisher-hornbill assemblage (“Coraciiformes”). Analysis of 56 morphological characters supports monophyly of a clade including Sylphornithidae and crown group Piciformes and results in sister group relationship between Passeriformes and a clade including Primoscenidae and the early Miocene Zygodactylidae. However, an analysis in which the search was constrained to trees supporting piciform affinities of the Primoscenidae resulted in trees that were only five steps longer than those from the primary analysis. The character evidence for each hypothesis is discussed. The systematic position of the Primoscenidae appears to be connected to the identity of the sister taxon of crown group Piciformes, as the primary search indicated Upupiformes (hoopoes and wood-hoopoes) and Bucerotiformes (hornbills) as sister taxa of Piciformes, whereas the constrained search resulted in sister group relationship between Coliiformes (mousebirds) and Piciformes. Songbirds do not show the slightest indication of a zygodactyl foot but in these birds the hindtoe is greatly elongated, an alternative strategy to increase the grasping capabilities of the foot. If Passeriformes are indeed the sister group of the clade (Primoscenidae + Zygodactylidae), these birds would be an example that, in closely related taxa, selection towards the same functional demands can result in entirely different morphological specializations.

Charles Darwin’s bird collection and ornithological knowledge during the voyage of H.M.S. “Beagle”, 1831–1836

Abstract: This paper analyses Charles Darwin’s bird collection and the ornithological knowledge he derived from it during the voyage of H.M.S. “Beagle”. Darwin collected 468 bird skins, 10 detached parts of the lesser rhea, and the nests and eggs of 16 different taxa as well as 14 whole birds and 4 parts of birds which he preserved in spirit. He labelled these specimens with a number tag only, cross-referring the number to a notebook entry. Partly because of his limited ornithological knowledge and partly because he was confronted at times with entirely unknown birds, Darwin was often unable to apply the correct generic designations and gave his South American specimens English and Spanish names from literature and the local tongues, as well as the scientific generic names of European birds. Back home, it was John Gould, the prominent ornithologist of the Zoological Society of London, who made sense of Darwin’s collection, among his many other scientific achievements correctly identifying the Galapagos finches as a group of closely related birds. Darwin’s bird collection did not receive much attention in the latter part of the 19th century. Most of the specimens had their original labels removed and replaced by ones of the custodian institution. Today, original Darwin specimens stemming from the “Beagle” voyage are to be found in at least eight different institutions, but almost half of the bird specimens Darwin collected on the “Beagle” voyage are not accounted for. The appendix to this paper lists for the first time all the birds which Darwin collected during the voyage. Darwin’s famous book On the origin of species hardly draws upon any ornithological examples from his voyage on the “Beagle”. Nevertheless, Darwin contributed much to ornithology. His collection contained 39 new species and subspecies of birds, mainly described by Gould, and some birds from populations now extinct, and he also made a few very good field observations, published in the sections of The Zoology of the Voyage of H.M.S. Beagle dedicated to birds.

Known and predicted African winter distributions and habitat use of the endangered Basra reed warbler (Acrocephalus griseldis) and the near-threatened cinereous bunting (Emberiza cineracea)

Abstract: The Basra reed warbler (Acrocephalus griseldis) and the cinereous bunting (Emberiza cineracea) are the only two Western Palearctic passerine bird species that overwinter in East Africa and are classified by BirdLife International as endangered and near-threatened, respectively. To refine the African wintering ranges of these two species, we made an effort to collect as much distributional data as possible. We then used the available point-locality data to predict the wintering distributions using a Geographic Information Systems (GIS) based inductive modelling technique called BIOCLIM. For this purpose, we developed four environmental GIS layers that are presumed to reflect the environmental preferences of migrant birds. Our data showed that the known winter distribution of the Basra reed warbler was concentrated in Kenya, Tanzania, Malawi and Mozambique, where it was usually found in dense vegetation growing in coastal scrub, woodland thickets, swamps, marshes, flooded pools and grasslands, and along ditches and edges of rivers, ponds, lagoons and lakes. The predicted winter distribution of this species includes most of East Africa but, given the habitat preferences of this species, is probably limited to low-lying areas near the coastline. The known winter distribution of the cinereous bunting is so far limited to Eritrea, where the species has been observed in October, November, February and March, in sparsely vegetated, sandy or rocky habitats on coastal plains and deserts. The predicted winter distribution of this species includes the plains and hills along the Red Sea coasts in southern Egypt, Sudan, Eritrea, Ethiopia and Sudan, as well as a few inland areas in Sudan, Ethiopia and Kenya.

Short records of marsh warbler (Acrocephalus palustris) song provide indices that correlate with nesting success

Abstract: The migrant Marsh Warbler (Acrocephalus palustris) has a complex song repertoire, but such complexity makes quantitative comparison of songs between individual males both time consuming and challenging. We investigate a streamlined method of song analysis that uses 2-min records of song to pro- vide simpler relative indices of repertoire size, includ- ing the use of capture-recapture and species-richness models. For each male, three attributes of song were determined: the song complexity, the total repertoire elements and the estimated repertoire size based on the Burnham and Overton jackknife method. Males with higher song indices tend to have greater nesting suc- cess, suggesting that even short records of song can indicate male quality to prospective female mates. Why should male Marsh Warblers have long and sustained songs when only 2-min records correlate with nesting success? Assuming that song advertises the quality of the male, and that the quality of such advertisement is sustained throughout the male's song period, we argue that the female may need to have only brief exposure initially to that song to assess its quality and hence the quality of the male. More continuous periods of song may reinforce that initial choice by the female, and allow males to remain conspicuous to transient females moving around the territories of potential male mates.

Song dialects on the Atlantic islands: goldcrests of the Azores ( Regulus regulus azoricus , R. r. sanctae-mariae , R. r. inermis )

Abstract: Territorial songs in island populations of songbirds are often highly divergent from those of neighbouring continental relatives. This is shown for the three goldcrest subspecies (Regulus regulus azoricus, R. r. sanctae-mariae and R. r. inermis) endemic on six islands of the Azorean archipelago. All investigated populations display a high intra- and inter-individual acoustic variation. On each island, up to six different song types have been found; and a single male sings up to three types. In contrast, all northwestern European populations of R. r. regulus and R. r. anglorum share only a single song type. In playback experiments, none of 18 tested dialect songs of Azorean goldcrests evoked notable territorial reaction in German and Czech goldcrest males (ssp. regulus). Two differing dialect groups of the goldcrest can be distinguished on the Azores. Populations of the eastern islands, Sao Miguel and Santa Maria, share common song types which are not found on the islands of the central and western groups. Dialect repertoires on the westernmost islands, Flores, Faial and Pico, are dominated by a different song type. In the geologically younger western crater of Sao Miguel, both western and eastern song types coexist. Acoustic similarities to a population from neighbouring Terceira suggest the western part of Sao Miguel as the origin for the westward expansion of R. regulus on the Azores.

Habitat preferences of tree pipit (Anthus trivialis) and meadow pipit (A. pratensis) at sympatric and allopatric localities

Abstract: Habitat preferences of the tree pipit (Anthus trivialis) and the meadow pipit (A. pratensis; Passeriformes: Motacillidae) were observed during the years 1998–1999 at three localities in the Czech Republic; two with one pipit species only, and a third with both species present. We investigated one of the possible mechanisms allowing syntopic coexistence—different habitat selection. We characterised territories of each pipit pair by the habitats present in the territory (defined by dominant plant composition) and by quantitative parameters (territory size, height and density of the vegetation, number of look-outs of different height categories, and proportion of wet ground). Tree pipits preferred significantly higher vegetation of lower density than meadow pipits, and there was generally a higher number of high look-outs in their territories. However, in some of the preferred territories at the allopatric locality of the tree pipit, steep hill slopes could well substitute for higher look-outs, which were almost absent. The two pipit species at the sympatric locality occupied very different habitats, which was also reflected in quantitative parameters of their territories. The available data of pipit habitat at different European localities show that the two species can occupy a much wider range of habitats. The habitat separation in sympatry might therefore be one of the mechanisms allowing syntopic coexistence of both species.

Do greylag geese (Anser anser) use traditional roosts? Site fidelity of colour-marked Nordic greylag geese during spring migration

Abstract: In 1995 to 2000, site-fidelity of colour-marked Nordic greylag geese (Anser anser) was examined during spring migration in the Rheiderland, an important stopover site in NW Germany. The results demonstrated that site fidelity in greylag geese depends very much on the mating status of the geese. Paired birds showed a significantly higher site fidelity than unpaired adults. There was no difference in the length of the roosting period between the two social groups. The year-to-year return rate of individuals showed significant differences in relation to the individual breeding success. Birds with high numbers of young showed a significantly higher return rate than birds with low numbers of young.

Morphometrics of the pink-footed shearwater (Puffinus creatopus): influence of sex and breeding site

Abstract: We present morphometric data for the pink-footed shearwater (Puffinus creatopus) from both Chilean breeding colonies on Isla Mocha and Juan Fernandez: weight, total length, wing length, tail length, head length, three bill and three tarsus size measurements and length of middle toe. Significant differences were found for most measurements between males and females as well as between birds from the two different breeding localities. In general, males were bigger than females, and birds from Juan Fernandez were bigger than those from Isla Mocha. Geographic differences most likely reflect some kind of ecomorphological adaptation. Some variables, especially the total length of head, seem to be useful for sex determination in the field.

Nestling characteristics and identification of the lesser spotted eagle Aquila pomarina, greater spotted eagle A. clanga, and their hybrids

Abstract: The lesser spotted eagle Aquila pomarina and the greater spotted eagle A. clanga are closely related endangered raptors whose taxonomic status, field iden- tification, and ultimately conservation, have been com- plicated due to morphological similarity. However, the partial overlap in morphological features may also in- volve hybrids, which are known to exist, but which have so far been poorly described. This study investigated spotted eagle nestlings in Estonia, pre-identifying them according to mitochondrial DNA, nape patch and the appearance of their parents. Relative size of bill and toes (corrected for nestling growth) enabled us to separate the smaller A. pomarina, but hybrids were as large as A. clanga. All three groups had distinct plumages with hybrids being intermediate; the separation was clearest using both size and plumage indices. In all, 164 of 168 birds were correctly identified using a three-step proce- dure, separating: (1) A. clanga, having no nape patch; (2) 9 of 13 hybrids according to plumage index; and (3) the remaining hybrids by their large size (at least two fea- tures over the mean+2 SD values of A. pomarina). Knowing the sex helped to interpret size, but not plumage, characteristics, and its overall value for assisting identification was not high. The results support the view that spotted eagles with intermediate characters are usually hybrids which can be recognised by their appearance.

Blood sampling does not affect fledging success and fledgling local recruitment in coal tits (Parus ater)

Abstract: In order to assess the potentially harmful consequences of blood sampling in nestling coal tits (Parus ater), we analysed fledging success, fledgling local recruitment and recruit natal dispersal for nestlings originating from 27 blood-sampled broods and nestlings from 39 control broods. No adverse effects of blood sampling were detectable.

Habitat use of nightjar (Caprimulgus europaeus) in an Austrian pine forest

Abstract: The Steinfeld in Lower Austria supports a population of European Nightjar (Caprimulgus europaeus) which was extensively studied during 1997 and 1998. The study area encompassed a pine forest of 20 km2. The population densities of 1.05 and 1.25 territories/km2, respectively, lies within the range found in central European populations. Annual monitoring until 2001 has shown the population to be stable. To gain an insight into habitat use of the species, various habitat-related parameters were measured inside and outside the territories, namely structure of trees, density of trees, structure of undergrowth vegetation and structure of clearings. Discriminant analysis was applied to assess the factors responsible for habitat choice of the Nightjar population. The findings showed that the Nightjars’ territories were frequently centered on a large clearing with an area of at least 0.7 ha. Clearings less than 50 m wide were not colonized. The requirement for a minimum width of a clearing in addition to a minimum area probably relates to better hunting conditions. Nightjars prefer trees where the lower edge of the crown is on average 4.38 m higher than at control points so that males can churr from dead branches immediately below the canopy. Such trees were found on the edge of clearings in the forest, and the edge of a clearing thus had a pronounced effect on the quality of a territory. In contrast to reports in the literature, neither the proportion of bare patches of ground nor the average height of undergrowth vegetation was found to be decisive for territory selection.

Sexual dimorphism in relation to winter foraging in the white-backed woodpecker ( Dendrocopos leucotos )

Abstract: Male white-backed woodpeckers (Dendrocopos leucotos) in a 250-km2 study area in western Norway are significantly larger than females in bill length and depth, wing and tarsus lengths, and bodyweight During the winters (October–March 1985–2002), most pairs were observed within their breeding territory where both sexes foraged mainly in grey alder and birch trees, and visited trees of the same tree height and stem width However, males foraged more frequently on dead trees and on trees broken by storms Males also used more trees with less bark cover, foraged nearer the ground and used foraging sites of larger diameter Furthermore, males practised more deep wood-pecking and less bark-pecking than females Unlike in other sexually dimorphic woodpecker species, the foraging niche breadth in wintering white-backed woodpeckers showed only minor sexual differences, and the sexes overlapped significantly in all parameters examined Since previous studies in the area have shown that the sexes overlap considerably in use of their territory, it was expected, as found in other size dimorphic woodpeckers, that the larger male would displace the supposedly socially subordinate female to suboptimal feeding sites In our area, the sexes were rarely seen together, and no sign of aggression between the sexes was observed Despite the sex-specific differences found in the foraging behaviour of the birds, it is not obvious how the differences should be related to size dimorphism

Nest sites and breeding ecology of the Másafuera Rayadito (Aphrastura masafuerae) on Alejandro Selkirk Island, Chile

Abstract: The first nest sites of the endemic Masafuera Rayadito (Aphrastura masafuerae) are described, the first one being found on 16 December 1992. Masafuera Rayaditos breed in small natural holes in steep rocks, the nest being hidden within the rock and not visible through the 3 cm-wide entrance. All nest sites were located in the summit region of Alejandro Selkirk Island above 1,200 m altitude, characterised by fern stands. Nesting has been reported from early December to late January. Feeding frequency increases only slightly during nestling time. Both parents feed the nestlings in similar proportions. During the daily round no regular variation in feeding frequency occurs, although it is often higher during the first hours after sunrise. In general, it decreases strongly when a Masafuera Hawk (Buteo polyosoma exsul) is present close to the nest site. It hunts intensively on Rayaditos, both adults and juveniles. Habitat destruction and predation pressure have caused the Masafuera Rayadito to be the most endangered bird species in Chile (total population c. 140 individuals). More detailed studies on its breeding ecology are urgently needed, especially on reproductive success.