We investigated apparent survival (i.e. survival confounded by permanent emigration) on the basis of a colour-ring programme in which individual Lesser Black-backed Gulls Larus fuscus and Herring Gulls Larus argentatus could be monitored over time. The work was conducted in a large, mixed colony in the western Wadden Sea (Texel), where measures of fecundity were collected simultaneously. In Herring Gulls, we found a mean apparent annual adult survival of 79% in females and 86% in males. Additive year effects rather than sex provided highest model support in Lesser Black-backed Gulls, in which apparent survival for both sexes combined varied between 81% and 100% (mean ≈91%). Breeding success in Lesser Black-backed Gulls was significantly lower than that of Herring Gulls. Lesser Black-backed Gulls experienced four consecutive breeding seasons with very low fledging rates (2006–2009) as a result of cannibalism (60–67% of all hatchlings). Chick predation was generally lower in Herring Gulls. A strong population increase in Lesser Black-backed Gulls coincided with substantial population declines in Herring Gulls in the Wadden Sea in the late 20st and early 21st century. In Lesser Black-backed Gulls, apparent survival declined by about 10% in the last two study years, which could, in combination with the low fecundity, halt the current population increase. We suggest that future work should concentrate on underexplored aspects affecting fecundity and survival such as intermittent breeding and sexual differences in migration, foraging and breeding effort.

In the period 1998–2010 the endemic subspecies of the Eurasian Spoonbill Platalea leucorodia balsaci breeding in Mauritania has decreased in numbers considerably. The causes for this decline are unknown. This study aimed to investigate the diet of the species. We analysed faecal material collected in the breeding colonies in 8 different years. The results show that Mauritanian Spoonbills almost exclusively eat shrimp (59.7%) and small fish (35.4%), the latter being dominated by Gobiidae (20.8%), Soleidae (4.8%) and Mugilidae (2.8%). Another 10 fish families were represented in small proportions. Shrimp were quantified on the basis of (parts of) mandibles present in the samples. All prey items eaten by the Spoonbills were extremely small. Diet composition of adult birds and chicks appeared to be similar. There was great variation in diet composition of adults between years, but there was no trend in any of the major diet components over the study period. This indicates that the decline of the Spoonbill population is not correlated with changes in food composition. Our diet study has been of a qualitative nature. Considering the dramatic population decline we plea for a more detailed ecological study of the species, including a quantitative approach of food intake and foraging conditions.

In 1974 R. de Naurois and F. Roux proposed that the distinct morphology of Eurasian Spoonbills Platalea leucorodia breeding on offshore islands in the Banc d'Arguin, Mauritania, in comparison with the sympatrically wintering northwest European breeding Spoonbills Platalea leucorodia leucorodia, justifies recognition as a separate subspecies Platalea leucorodia balsaci. This proposal is examined here on the basis of variation in nuclear DNA, microsatellites identified earlier for P. minor and P ajaja. We show that there is significant variation between Spoonbills breeding in Mauritania (n = 25) and the sympatrically wintering conspecifics breeding in the Dutch Wadden Sea (n = 105). Of the total genetic variation among the 130 individuals, 6.3% is attributable to variation between the two breeding areas (93.7% of the variation is within breeding areas). Pairwise F_ST values showed low genetic differentiation (FST'S < 0.012) among breeding colonies within The Netherlands. The level of genetic differentiation indicates that the level of gene flow between The Netherlands and Mauritania is much lower (∼4–5 individuals/generation) than among the Dutch colonies on separate Wadden Sea islands. Field observations on individually colour-marked birds from The Netherlands indeed suggest extensive dispersal within northwest Europe, with some introgression of leucorodia genes into the balsaci population. The level of microsatellite distinctiveness between sympatric populations of the two subspecies is similar to that recorded for subspecies of other migrant birds, and as such justifies the subspecies status of the Mauritanian Spoonbill.

The White-breasted Cormorant Phalacrocorax carbo lucidus occurs in Central, West, East and South Africa. The West African population breeds on the Cape Verde Islands and along the Atlantic coast from Mauritania to Guinea. The species forages in marine, brackish and fresh waters and is thought to be (almost) completely piscivorous. However, data on diet are poorly available and completely lacking for the West African population. We collected regurgitated pellets at three sites, in Mauritania (Island of Zira, Banc d'Arguin) and Senegal (Ilot aux Oiseaux, a small islet in the estuary of the Senegal River and Ile de la Madeleine near Dakar). On the basis of otoliths, 34 fish species belonging to 21 families were identified. There was great variation in the diet of the cormorants at the different sites, with Haemulidae and Batrachoididae being dominant on Ile de la Madeleine, Ariidae and Cynoglossidae on Ilot aux Oiseaux and Sparidae, Mugilidae and Batrachoididae on the Island of Zira. Most fish consumed were coastal species, many of which may also enter brackish or fresh waters. The cormorants mainly ate benthic and bentho-pelagic fish species varying in size between 10 and 20 cm. There was great variation in the number of otoliths per pellet at the different sites with a remarkably small number in the Zira sample. We investigated whether a small number of otoliths per pellet can be explained by the prey fish being larger or by the otoliths being more eroded. The latter might be an indication that part of the otoliths had been totally dissolved and thus disappeared from the samples. Neither fish size nor extent of wear could explain the small number of otoliths in the Zira sample. A comparison between artisanal fisheries catches and the diet of the cormorants showed hardly any overlap for the Senegalese sites. However, substantial overlap was found at the Banc d'Arguin in Mauritania. These differences can be explained by the high proportion of pelagic species caught in the Senegalese sites.

We studied the movements, home ranges and roost site preferences of three first-year Cinereous Vultures Aegypius monachus after they fledged at the Türkmenbaba Mountains, Eskiehir, western Turkey. We captured chicks at the nest in 2009 and 2010 and fitted them with GPS-GSM transmitters. After fledging, we received a total of 993 locations from all birds during 105–148 days of tracking. Tracked birds initially used small foraging areas, covering a mean 90% kernel home range of 356 ±134 SE km², and on average moved <10 km per day. As they started to migrate, daily movements increased to 59.3–120.3 km on average and took place largely during midday. Birds preferred to roost at sites with higher altitude, steeper slope and more wooded land. Our data suggest that first year birds from Turkey disperse south in October and November to desert habitats in middle latitude Arabia, and may cover up to 2765 km during migration.

Immature European Honey Buzzards Pernis apivorus are believed to remain in tropical Africa during the first years of their lives. We studied their movements during this period with the aid of satellite telemetry. After crossing the Sahara Desert on autumn migration, all six tracked young buzzards stopped at relatively northerly latitudes, between 9.9–13.6°N. Of the five individuals that continued transmitting, four made south-directed movements, mainly in November, to areas located further south or east within latitudes 1.7–9.8°N. Three young buzzards were tracked for more than three months in tropical Africa, and these individuals continued to perform extensive movements within the tropics throughout the tracking period. They travelled between 2,430 and 3,990 km (minimum distances) during 13 to 14 months, in which they visited several sites. In contrast, adult birds migrate directly to their wintering sites where they remain stationary within restricted territories. The mobile life of young Honey Buzzards during the period prior to their first northbound migration may be associated with responses to seasonal weather changes in the tropics and prospecting behaviour. These movements may also reflect intraspecific competition which might be catalyzed by forest degradation and fragmentation.

We set out to explore whether changes in fecundity and survival (or both) of European Honey Buzzards were associated with trends observed in The Netherlands. We used standardized monitoring data on numbers and reproduction from several study plots in The Netherlands over the period of 1974–2005. Survival estimates were based on recoveries of Honey Buzzards ringed throughout Europe (collated by EURING and individual ringing stations). Based on these values we computed the annual population growth rate with a time invariant population model, and used elasticity analysis to detect the parameter with the strongest influence on growth rate. Lambda was smaller than 1, suggesting a population decline, but confidence intervals around lambda were relatively wide. Elasticity of adult survival was much higher than of any other life history parameter, indicating that adult survival has potentially the greatest impact on annual population growth. Because data on reproduction varied strongly we estimated a 95% confidence interval for annual population growth by bootstrapping the reproduction data. Furthermore, we analysed the influence of stochastic food availability (i.e. wasp abundance) on reproduction, and through this demographic factor, on the population trend. The stochastic model suggests a clear population decline, which is consistent with observed declines across much of northern and western Europe (including The Netherlands). For the growth rate λ to reach 1, a reproductive output of 1.16 young per pair was calculated to be necessary, much higher than the 0.53–0.88 found in two study sites in The Netherlands.

Development during the relatively short time that young spend in the nest is crucial in a bird's life history. The rate of nestling growth strongly depends on numerous environmental and social factors, even within the same species or population. In the present study I examine the relative contributions of brood size, hatching asynchrony, hatching date and feeding rate in determining intraspecific variation in the growth of Eurasian Blackcap Sylvia atricapilla nestlings. I found a significant effect of brood size, hatching order and date on nestling development. However, the effect of hatching order and date was significant only for young nestlings and it gradually disappeared with nestling age. The only factor significantly affecting nestling development just before fledging was brood size. Nests of four siblings produced the heaviest young with the longest tarsi. This probably resulted from the highest feeding rate per nestling observed in broods of four nestlings. The study shows that for Blackcaps breeding in a good year a brood size of four is the optimal number, and that younger siblings can catch-up with older nest mates.

Across most of the tropics it is often difficult to tell whether extensions of known range by bird species reflect genuine change or are artefacts of increased observation. Yellow-vented Bulbul Pycnonotus goiavier is a mainly Sundaic passerine known from southern Indochina (southern Thailand, Cambodia and southernmost Vietnam) for many decades. The first Lao record came only in 1996 but since then the species has spread north through Lao PDR along the Mekong and some major tributaries. All Lao records are from the lowland plains, in non-forest habitat. Inspection of the locations of records and of birdrecording patterns in Lao PDR over time indicate that this bulbul's northern expansion, paralleled by one in adjacent Thailand, is surely not simply the belated finding of a species long-overlooked. Both climate change and habitat change (forest conversion and fragmentation) are plausible causes. That five of six non-forest passerines that have colonised (or massively expanded in) Lao PDR in the last 30 years are from the south, with one from the west but none from the north, may suggest climatic change as the cause, but their rates of expansion far outstrip northward temperature movement. While Yellow-vented Bulbul's change in national status is obvious, even though Lao PDR is one of the least known countries for birds in South-east Asia, disentangling the roles of these two simultaneous major effects in avifaunal change in South-east Asia is challenging.

The Great Tit Parus major is one of the most intensively studied birds and such studies have contributed greatly to the current understanding of the evolution and ecology of natural populations. However, despite its wide geographic distribution and high variation in life history traits among regions, most ecological studies are concentrated in Europe, and there are relatively few studies elsewhere. We studied the breeding ecology of a Great Tit population in northern Japan and compared their breeding parameters to those described previously for European populations. This population was characterized by a long breeding season, up to four months from May to as late as the end of August (egglaying to fledging), and a high frequency of multiple brooding (≥60%) including two occasions of third broods. In addition, clutch size was large with a mean of over ten, compared to less than eight in European populations at the equivalent latitude. The high productivity of the studied population may be a consequence of the high diversity and abundance of prey items in northern Japan associated with past and present climatic characteristics.

In male passerines, the accumulation of sperm in the sperm reserves causes the cloaca to become enlarged, forming the cloacal protuberance (CP). In Blue Tits, the timing of breeding differs considerably between pairs. Hence, when catching a male during the breeding season it may be unclear whether he is in a reproductively active state (i.e. producing sperm). Here, we show in captive Blue Tits Cyanistes caeruleus that CP volume is increased in males in a reproductively active state when compared to the same males in a reproductively inactive state. However, there was some overlap in CP volume when comparing the values in reproductively active and non-active states. Measurements of CP volume at a single time point, therefore, do not allow the researcher to reliably determine an individual's reproductive status.

It is well established that once birds have laid their eggs they sometimes incubate non-egg objects. However, reports of birds incubating solely non-egg objects (without prior manipulation by researchers) are rare. Here we report on our observation of a Long-billed Dowitcher Limnodromus scolopaceus incubating a clutch composed entirely of mammalian bones. To our knowledge, this is the first report on (a) incubation of foreign objects in Scolopacidae, (b) incubation of a ‘clutch’ composed entirely of bones, and (c) incubation of foreign objects in a nest atypical for this species in both construction and nest habitat. We discuss possible explanations for this presumably maladaptive behaviour.

The subspecies of Northern Goshawk Accipiter gentilis present clinal plumage variation. However, aberrant plumages are exceptional. On 2 February 2012, in Sędziszów (southern Poland), a dead Northern Goshawk with aberrant plumage was found. The bird was mostly beige but had retained the banding pattern in the flight feathers and streaking on the breast and underwing coverts. Birds in the described aberrant plumage might be confused with the Eastern Palearctic subspecies A. g. albidus.