Baltojo gandro Ciconia ciconia gausumas ir erdvinis pasiskirstymas, perėjimo buveinių pasirinkimas, perėjimo sėkmingumas ir pavasarinis atskridimas arealo šiaurės vakarų periferijoje

In this study, changes during the period 1994–2010 in White Stork abundance and spatial distribution, as well as in nest-site selection were determined; regularities in breeding habitat selection and the effect of some habitat characteristics on the breeding success were investigated. The White Stork habitat selection study was carried out in the north-western periphery of the species’ range on a sample, comprising 8.4% of the total breeding population of this species, concentrated in an area covering just 1.1% of its range. It was revealed that a considerable increase in the White Stork abundance in 1994–2010 coincided with the adaptation by birds to breeding at a new nest-site – on poles of overhead electricity lines. However, from the standpoint of reproduction, this change in the White Stork nesting behaviour was partly non-adaptive due to significantly lower breeding success in nests built on poles of operating overhead electricity lines. Data on the White Stork first spring arrival, collected during the period 1961–2000, revealed a significant advancement of spring arrival date to the breeding grounds in the north-western periphery of the range. Factors, affecting the first spring arrival to breeding grounds, were determined. The main threats facing the breeding White Storks were determined, their importance was assessed, and recommendations for the mitigation of these negative impacts were prepared for this species of the EU conservation concern

Abundance and spatial distribution, breeding habitat selection, breeding success and spring arrival of the white stork Ciconia ciconia in the north-western periphery of the range

In this study, changes during the period 1994–2010 in White Stork abundance and spatial distribution, as well as in nest-site selection were determined; regularities in breeding habitat selection and the effect of some habitat characteristics on the breeding success were investigated. The White Stork habitat selection study was carried out in the north-western periphery of the species’ range on a sample, comprising 8.4% of the total breeding population of this species, concentrated in an area covering just 1.1% of its range. It was revealed that a considerable increase in the White Stork abundance in 1994–2010 coincided with the adaptation by birds to breeding at a new nest-site – on poles of overhead electricity lines. However, from the standpoint of reproduction, this change in the White Stork nesting behaviour was partly non-adaptive due to significantly lower breeding success in nests built on poles of operating overhead electricity lines. Data on the White Stork first spring arrival, collected during the period 1961–2000, revealed a significant advancement of spring arrival date to the breeding grounds in the north-western periphery of the range. Factors, affecting the first spring arrival to breeding grounds, were determined. The main threats facing the breeding White Storks were determined, their importance was assessed, and recommendations for the mitigation of these negative impacts were prepared for this species of the EU conservation concern

Tawny Owl females of intermediate colour morph reproduce better and increase in a local polymorphic population

Individuals of the same population with differing melanin plumage colouration can respond differently through fitness to environmental stressors. In a local population of Tawny Owls (Strix aluco), we collected individual-based data on nesting attempts of this well-known colour polymorphic species between 1985 and 2014. We studied whether body size, condition, demographic parameters and habitat around occupied nest sites differ among grey, intermediate and brown coloured females. The proportions of females belonging to each of the three colour morphs in the local population changed during the study period, withintermediate individuals becoming more frequent in the last decade. Females were similar in body size and achieved similar body condition during breeding irrespective of plumage colouration. Although most of the analysed demographic parameters were not statistically significantly related to the colour morph, the intermediate owls raised more nestlings in a lifetime and tended to have higher recapture probability. We found little support for habitat and morph associations. In summary, we propose that the increase in intermediate Tawny Owl colour morphs in this local population is associated with their better reproductive performance compared to the other morphs

Tawny Owl females of intermediate colour morph reproduce better and increase in a local polymorphic population

Individuals of the same population with differing melanin plumage colouration can respond differently through fitness to environmental stressors. In a local population of Tawny Owls (Strix aluco), we collected individual-based data on nesting attempts of this well-known colour polymorphic species between 1985 and 2014. We studied whether body size, condition, demographic parameters and habitat around occupied nest sites differ among grey, intermediate and brown coloured females. The proportions of females belonging to each of the three colour morphs in the local population changed during the study period, withintermediate individuals becoming more frequent in the last decade. Females were similar in body size and achieved similar body condition during breeding irrespective of plumage colouration. Although most of the analysed demographic parameters were not statistically significantly related to the colour morph, the intermediate owls raised more nestlings in a lifetime and tended to have higher recapture probability. We found little support for habitat and morph associations. In summary, we propose that the increase in intermediate Tawny Owl colour morphs in this local population is associated with their better reproductive performance compared to the other morphs

Understanding recreational targets and ecological consequences: increased northern pike stocking reflected in top avian predator diet

Fish stocking is commonly used to enhance recreational fisheries; however, the side effects of stocking at the ecosystem scale have rarely been tested. Avian predators, because of their high position in food webs, can serve as indicators of environmental change, including prey-species abundance. The scope of this study was to understand whether recent changes in northern pike (Esox lucius) stocking on a national scale could cascade through food webs and significantly shape the diet of a predator––the white-tailed eagle (Haliaeetus albicilla). The stocking of pike in state-owned waters in Lithuania has increased two- to threefold since 2005. A significant increase in the proportion of pike in the breeding-season diet of the white-tailed eagle has also been observed. We explain the increase in pike in the predator’s diet as being a causal consequence of pike stocking. We encourage consideration of the entire food web when launching/terminating recreational fish stocking programmes

Spatial and temporal variations in the White-tailed Eagle Haliaeetus albicilla breeding diet revealed by prey remains

Capsule: Despite its population increase, the White-tailed Eagle Haliaeetus albicilla has not become food-limited, and does not pose a serious threat to birds of conservation concern in the region east of the Baltic Sea. Aims: We aimed to test variations in the main prey groups and dietary niche breadth of White-tailed Eagles through the years and along an environmental gradient as well as to evaluate the extent of predation on bird species of conservation concern. Methods: Prey remains were collected during nestling ringing from successful nests located in Lithuania. Results: The frequency of the prey groups varied along an environmental gradient, with a general pattern of increasing avian prey consumed by pairs breeding in areas with less abundant aquatic habitats. The frequency of alternative prey (i.e. terrestrial birds, mammals) and dietary niche breadth did not increase between 2005 and 2018 and during which time the White-tailed Eagle population nearly doubled. Instead, the occurrence of Northern Pike Esox lucius remains, which was the most frequent single prey species, increased throughout the study period. Bird species of conservation concern constituted only a small fraction of all the prey identified. Conclusions: The White-tailed Eagle has not become more dependent on alternative prey despite its population increase

Mtdna d-loop genetic diversity of common quail (Coturnix coturnix) migrating through Ukraine and Spain

Populations of common quail (Coturnix coturnix) have recently been declining in Europe. This is the first study of common quail in eastern Europe using molecular markers. The mtDNA D-loop genetic diversity of common quails migrating through Ukraine was analyzed and compared with that of birds migrating via northern Spain in 2017–2018. In samples from 77 birds, 32 polymorphic sites and 30 haplotypes (H1–H30) were identified, only 4 of which were common for birds sampled in both Ukraine and Spain. Phylogenetic analysis indicated 2 well-supported clades. Found were 3 haplotypes clustered in 1 phylogenetic clade only in common quails sampled in Ukraine. The results can be used for the identification of different flyways, particularly for common quails of eastern European origin

The genetic diversity and structure of the European Turtle Dove Streptopelia turtur

The European Turtle Dove, Streptopelia turtur, a long-distance migrant wintering in Africa, is a widespread Palearctic species. This species is classified as vulnerable and is undergoing a long-term demographic decline. The results of the previous study (based on mitochondrial (mtDNA) cytochrome-b (cytb) sequences of birds from Western and Southern Europe) indicated that the species was not genetically structured. We analysed the mtDNA cytb and D-loop of 258 birds collected from Morocco, Spain, and Ukraine. High genetic variability, expressed by haplotype diversity and nucleotide diversity, was revealed in both cytb (Hd = 0.905 ± 0.009, π = 0.00628 ± 0.00014) and the D-loop (Hd = 0.937 ± 0.009, π = 0.01502 ± 0.00034). SAMOVA and principal coordinates analysis revealed the birds belonged to two genetically distinct groups. One group included birds collected in Spain, while birds sampled in Morocco and Ukraine formed another group. Furthermore, significant genetic differentiation was identified between Turtle Doves from Morocco and Ukraine, and certain Spanish samples. The present results indicate that specific management and conservation plans relevant for the species in various regions should be applied. However, further nuclear DNA research and new studies (particularly in Eastern Europe) are necessary for the decisive results on genetic structure of this species

Internationally important stopover area for the globally-threatened Common Pochard Aythya ferina in the Volga River delta

The Common Pochard Aythya ferina (hereafter Pochard), is a widespread freshwater diving duck of the Palearctic. A large and rapid decrease in abundance resulted in it being classified as Vulnerable in the International Union for Conservation of Nature’s (IUCN) Red List in 2015 and it is now considered to be a threatened species globally. The objective of this study was to provide reliable data on numbers and habitat use for Pochard in the delta area of the River Volga (southern European Russia) during their autumn migration. The total number of Pochard staging in the River Volga’s avandelta was estimated at c. 346,000–390,000 individuals in mid-November 2020 and c. 153,200–170,000 in mid-November 2021. Several sites with large numbers of staging Pochard were identified within the delta, and the Volga River delta currently holds the most important stopover concentrations of Pochard in the Palearctic. A large-scale monitoring and research programme is required for Pochard in the delta of the River Volga, because such information is essential for the effective conservation of this globally-threatened species

Recent changes in breeding abundance and distribution of the Common Pochard (Aythya ferina) in its eastern range

Background The Common Pochard (Aythya ferina) (hereafter Pochard), a widespread and common freshwater diving duck in the Palearctic, was reclassified in 2015 from Least Concern to Vulnerable IUCN status based on rapid declines throughout its range. Analysis of its status, distribution and the potential causes for the decline in Europe has been undertaken, but there has never been a review of its status in the major part of its breeding range across Russia to the Pacific coast. Methods We reviewed the scientific literature and unpublished reports, and canvassed expert opinion throughout Russia to assess available knowledge about changes in the species distribution and abundance since the 1980s. Results While accepting available information may not be representative throughout the entire eastern range of the species, the review found marked declines in Pochard breeding abundance in the last two decades throughout European Russia. Pochard have also declined throughout Siberia. Declines throughout the steppe region seemed related to local drought severity in recent years, necessitating further research to confirm this climate link at larger spatial scales. Declines in the forest and forest-steppe regions appeared related to the major abandonment of fish farms in western Russia that had formerly provided habitat for breeding Pochard. However, hyper-eutrophication of shallow eutrophic lakes, cessation of grazing and haymaking in floodplain systems necessary to maintain suitable nesting habitat and disappearance of colonies of the Black-headed Gull (Chroicocephalus ridibundus) in a number of wetlands were also implicated. Increasing invasive alien predator species (e.g. American MinkNeovison visonand Raccoon DogNyctereutes procyonoides) and increasing spring hunting were also thought to contribute to declines. Reports of expansion in numbers and range only came from small numbers occurring in the Russian Far East, including on the border with China and the long-established isolated population on Kamchatka Peninsula. Conclusions Widespread declines throughout the eastern breeding range of the Pochard give continued cause for concern. Although we could address all the potential causal factors identified above by management interventions, we urgently need better information relating to key factors affecting site-specific Pochard breeding success and abundance, to be able to implement effective actions to restore the species to more favourable conservation status throughout its breeding range