Journal of Ornithology最新文献

The arid belt of Central Asia constitutes a barrier for small landbirds during autumn migration. Some species that migrate from Siberia to Africa circumvent this barrier by taking a detour around the northern coast of the Caspian Sea. It becomes increasingly clear that at least some songbirds that migrate between eastern Europe and southern Asia also perform a detour along the northern edge of the desert. Trapping data from the northern fringe of the barrier collected in this study (Orenburg Region of Russia, 51° 22′ N, 61° 23′ E; September 2023) and from earlier studies performed west and east of our study site show that some songbirds that migrate from European breeding grounds towards south and south-eastern Asian wintering quarters make a direct crossing, whereas others make a detour and circumvent Central Asian deserts. Ecological differences between the species of migrants cannot explain the observed pattern. Those species that make a detour are the ones that are considered to have colonized Europe from their ancestral breeding areas east of the Ural Mountains most lastly.

The annual cycles of long-distance migrant species are synchronized with the local climatic conditions at their breeding areas, as they impact the availability of food resources. A timely arrival of individuals to the breeding grounds is crucial for achieving high fitness. Variation in factors influencing timing, including climate, may thus impact the life history of individuals. We studied between-individual variation in migration timing, in particular how local breeding climate influences arrival time and how early-arriving individuals achieve a timely arrival. We tracked individual Lesser Kestrel (Falco naumanni) with GPS tags across a gradient of latitude (37°–42° N) and longitude (6.5° W–16.5° E). Arrival time was influenced by the breeding latitude, the breeding longitude, and the local temperature, without any apparent influence of sex. The time of arrival at the breeding grounds was 6 days later for every degree increase in latitude and 2 days later for every degree increase in longitude. Lesser Kestrels from southwestern colonies achieve earlier arrival than conspecifics breeding at northeastern colonies, mostly due to earlier departure from their non-breeding grounds. While we found some effects of travel speed and stopover duration on arrival date, the latter was primarily influenced by food abundance and wind conditions en route. The large effect of departure date from West Africa on arrival date, relative to the more moderate influence of stopover duration close to breeding colonies, supports the idea that geographically uneven climate change may negatively affect fitness via ecological mismatches in the breeding area.

The beginning of reproduction is usually accompanied by a series of decisions including where to establish a territory, attract a mate, to lay eggs or give birth. These decisions might be influenced by the quality of potential partners but also conspecific neighbours. In birds, the quality of an individual can be signaled by song features, like song complexity. Besides choosing the right location for reproduction and mate attraction, we propose here that song may also influence the reproductive investment, in particular early maternal investment, which is known to be a sensitive determinant reflecting different allocation of females in relation to male quality and attractiveness. Here, we examined whether song quality of conspecific neighbours can stimulate various reproductive parameters in European Common Reed Warblers (Acrocephalus scirpaceus). Therefore, we performed field playback experiments advertising song of high and low complexity and examined their influence on settlement decisions, early maternal investment, and breeding success. The number of nests and start of egg laying did not differ between the two playback types but nests were significantly closer to high complex song playbacks. Furthermore, in the high complex song group, a significantly higher proportion of eggs was fully dark pigmented than in the low complex playback group. Nests near high complex playbacks were significantly more successful and significantly more offspring were produced. The results are discussed in relation to whether males use song to stimulate female investment and whether establishing a breeding location near a high-quality neighbour may be an additional aspect in settlement decisions.

Our study reveals for the first time in a quantitative manner the differences in eggshell thickness and elemental composition between pigment spots and adjacent plain eggshell regions in bird species from three developmental modes, i.e. altricial (Great Reed Warbler Acrocephalus arundinaceus), semi-precocial (Black-headed Gull Chroicocephalus ridibundus, Mediterranean Gull Ichthyaetus melanocephalus, Sandwich Tern Thalasseus sandvicensis and Black Tern Chlidonias niger) and precocial species (Western Capercaillie Tetrao urogallus and Black Grouse Lyrurus tetrix). From a broader biological/biogeochemical perspective, our data broaden the knowledge in the heterogeneity of elemental composition between adjacent spotted-plain regions of eggshells, previously demonstrated in galliform birds, which differ in colour for many chemical elements. These differences, however, were distinctive of individual species and varied between chemical elements. There emerged a clear and consistent trend of higher elemental concentrations within pigment spots compared to plain eggshell regions, particularly in the case of five elements: C, Pb, Cu, Cr and Al. The most important and novel finding of our study is that even though the eggshells of gulls and terns (semi-precocial species) and of the passerine (altricial species) were thinner in the spotted regions (there was thus less shell material) compared with those of precocials (the eggshells being thicker eggshells at the spots), the spotted regions of all these eggs contained disproportionally higher concentrations of most major and minor chemical elements. Hence, this appears to be a general rule across all birds, regardless of the eggshell thickness in the spotted or plain regions and/or their developmental mode. In other words, this finding confirms that the thickness of the eggshell itself does not affect the concentrations of elements, and that the key issue related to this is the presence of one or more protoporphyrin layers along with the accompanying pool of chemical elements within the spotted eggshell region.

Vultures are an indispensable part of a healthy and balanced ecosystem. Vultures migrate from breeding to wintering grounds to access resources which are otherwise unavailable. Despite the possible effect of climate change, their wintering habitat is not sufficiently studied. We studied wintering habitats of two Eurasian vultures—Griffon Vulture (Gyps fulvus; EGV) and Cinereous Vulture (Aegypius monachus; EBV) in northern India. Habitat distribution model (Maxent) and global circulation models (CCSM4, HadGEM2AO, MIROC5) were used to predict current and future (RCP2.6, RCP4.5 and RCP8.5 for 2050 and 2070) habitats of both the species. We identified influential habitat variables to determine current and future habitat suitability and suggested appropriate conservation measures. Model prediction showed that mean temperature of the driest quarter and precipitation of the wettest month were the two major influential variables with highest contribution, though landcover also played an important role. Suitable area expanse for EBV (12%) was smaller than EGV (38%) in the available 240,928 km². The predictive suitability map showed the dynamics of suitable and unsuitable habitats indicating range expansion (3–16%) and contraction (1–6%). Their shift was multidirectional occurring towards the Northwest, East, Southwest and Southeast. Across the scenario, impact of climate change was positive (net gain in suitable area) in most of the cases. The findings show that the Tarai districts need improvement in habitat management to provide safe roosting and foraging sites for Eurasian vultures with a large migratory pattern.

The use of unique markers in ornithology has a long history and is predicated on the assumption that markers have negligible effects on behavior and survival. The assumption that marks are harmless is particularly important with imperiled species. We studied the effects of two different marking schemes on Piping Plovers (Charadrius melodus), a small shorebird protected under the U.S. Endangered Species Act that is intensively monitored and managed. We used two marking schemes, (1) color bands and (2) uniquely engraved flags during breeding seasons from 2013 to 2023 to determine whether the injuries were causing additive mortality and thus actually limiting populations. We estimated the effect of perceived limping and injury (e.g., swelling, laceration, etc.) on chick and hatch-year survival. We detected injuries in some years and associated with both marking schemes (range 0.0–6.0%, average = 2.7% of marked chicks each year). Interval survival for banded chicks was like that of flagged chicks ((beta ) = − 0.55, 95% BCI: − 1.30–0.33, f = 0.92). Mean survival to fledging, however, was higher in years where flags were used ((overline{phi }=) 0.55 ± 0.14) than when bands were used ((overline{phi }=) 0.34 ± 0.14), but we surmise that this difference was partly conflated with negative density-dependent factors ((beta ) = − 0.49, 95% BCI: − 0.73 to − 0.25, f = 1.00) and predation. Our results show that pre-fledge survival of birds with uniquely coded flags was similar to that of birds receiving color bands. There was also no evidence that injured birds had a significantly lower hatch-year survival than those that were not injured. However, the relatively high (up to 6%) injury rate in some years remains a concern. Injury and survival rates need to be considered and evaluated when deciding on whether to mark individuals. Ultimately, wildlife practitioners should strive to use the best methods for information gathering and management, without negatively impacting the species.

This study examines the Mediterranean Gull (Ichthyaetus melanocephalus), utilizing GPS/GSM transmitters year-round for the first time on this species. The research covers habitat use, migration patterns, and breeding behaviors, tracking 19 birds captured at breeding colonies in Poland. To capture the birds and fit transmitters, we selected representative locations: islands in dam reservoirs, gravel pits, rivers, and lakes. Mediterranean Gulls nested mainly in colonies of Black-headed Gulls (Chroicocephalus ridibundus). By tracking birds with transmitters, we identified nine additional breeding sites within Poland, the Czechia, and Germany. We determined the mean length of phenological periods: breeding (76, April 10–June 26), autumn migration (11, June 26–July 7), winter (261, July 5–March 23), and spring migration (18, March 23–April 10). According to residence sites analysis, cropland was the most frequently used habitat during breeding (52.9%), while the open sea was predominant in winter (25.8%). We identified key wintering areas: the English Channel, the Utrecht–Antwerpen area, the North Sea coast, and the Irish Sea coast. One individual wintered along the coast of Portugal and near Malaga in Spain. An interesting discovery was the longer spring migration than autumn what involved visits to multiple potential breeding sites, leading to the mapping of a network of potential breeding areas. This underscores the need for proactive habitat protection and comprehensive conservation strategies. Given the Mediterranean Gull’s migratory behavior and lifecycle, the study advocates for it as a model for conserving migratory waterbirds.

The Eurasian Spoonbill (Platalea leucorodia) and the White Stork (Ciconia ciconia) are emblematic birds of high conservation interest. This article examines their range history in Europe since the end of the last Glacial by analyzing subfossil bone finds of both species, mostly from archaeological excavations. It is shown that two thousand years ago, White Storks occurred exclusively in the territory of the Roman Empire, i.e. the northern border of their distribution ran along the Rhine and Danube rivers. The north-east part of the continent, with its high population density today, was only colonized in the last few centuries. The Spoonbill’s patchy occurrence in Europe today appears to be a typical distribution pattern for this species. The subfossil findings also do not indicate a large, closed distribution area for any phase of the last 10,000 years. Some of its distribution islands (e.g. those in the Netherlands) have existed for thousands of years.

Changes in species geographic distributions, including those of migration routes, stopover sites, and over-wintering grounds, may affect the phenology of breeding and moult. The White-winged Tern (Chlidonias leucopterus) is a long-distance migrant which breeds in Eurasia and winters in Africa and Australasia. This species is known in the Eastern Mediterranean and the Middle East mainly during the migration seasons although it also breeds locally in eastern Turkey and the Persian Gulf. However, in the last decade, there has been an apparent change in the winter distribution of this species, with increasing observations of individuals during December–February in the Middle East, many of them in breeding plumage. Using data collected from specimens stored at the Natural History Museum at Tring (UK), ringing data from Israel, the online database eBird, and accompanying Macaulay Library (Cornell Lab of Ornithology), we described these recent changes in the seasonal distribution and annual moult cycles. While the birds that breed in the north begin to replace their black body feathers immediately at the end of the breeding season, the birds described here displayed the black body plumage (breeding plumage) throughout the winter (December–February), a plumage pattern that is offset by seven to eight months from those of the northern-hemisphere breeding populations. This might suggest yet-to-be discovered local breeding in the Middle East in February–April. In such cases as this, we hypothesize that examination of plumage phenology may help researchers investigate the timing of as yet unknown breeding phenology.

Although geolocator tracking of small passerines has become commonplace in the last two decades, this tool is still underutilized for gathering natural history data of migration in many species. Common Whitethroat (Curruca communis) is one of the most numerous Afro-Palearctic migrants. However, our knowledge of the species’ migration ecology remains limited. Here, we combine ring-recovery analyses with geolocator tracking to describe migration routes and population-specific non-breeding areas in this long-distance migrant. Linkages between breeding, passage and non-breeding areas based on ring-recovery records revealed a strong correlation in longitudes, indicating parallel migration system and population-specific non-breeding grounds in whitethroats. Migration route simulation using EURING data suggested a possible migratory divide in Central Europe in autumn, while broad front migration across the Mediterranean occurs in spring. Geolocator-tracked whitethroats from Czechia (Central Europe) and Latvia (North-eastern Europe) migrated to non-breeding sites in Central Africa, where they first resided in the Sahel region before moving farther to a second non-breeding site in November/December. Major stopovers were associated with crossing of ecological barriers. A single Latvian bird with a repeat track showed similar migration patterns in both years, possibly visiting the same non-breeding sites in consecutive years. Both ringing and tracking data revealed clockwise loop migration between breeding and non-breeding sites.