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Choosing an appropriate nest site is essential for successful breeding. Changes in land use cause populations of many species to decline although some species adapt to anthropogenic changes. The white stork Ciconia ciconia commonly uses artificial nest sites. Recently, white storks from Western Europe have been using landfills as feeding sites; the beginnings of this process are being observed in Central-Eastern Europe. The study aimed to determine factors influencing the probability of nest occupation and breeding effect in a Central-Eastern European population of white storks. We used long-term data from Western Poland on breeding effect, nest occupation, the structure supporting the nest, the proximity of the nearest landfills, landfill area, and land cover. The probability of nest occupation was significantly dependent on habitat quality (based on the share of the preferred type of land cover), the structure supporting the nest, and landfill proximity within a specific year. The breeding effect was influenced by habitat quality and nesting structure. We demonstrate that the type of nesting structure is an important factor influencing both the probability of nest reoccupation and breeding effect. However, the significance of landfills appears to be growing, and in recent years, storks prefer occupying nests closer to landfills, which may have significant consequences for the population of the white stork. [ABSTRACT FROM AUTHOR]

Interspecific or intraspecific destruction of eggs by other small bird species (Passeriformes) is a relatively rare behaviour. It is known from studies of several new world species from families Mimidae and Troglodytidae, but it has never been documented in the Eurasian wren (Troglodytes troglodytes). While studying the breeding biology of the white-throated dipper (Cinclus cinclus) in northern part of Central Slovakia, we documented seven events (frequency 1.8%) when Eurasian wren occupied a dipper's nest during the breeding season. None of these breeding attempts by the dippers was successful. In all cases, the breeding pairs abandoned their nest. Except of these seven cases, we also found an abandoned nest (situated in the nest box under a bridge) with damaged eggs of the white-throated dipper. According to the intact nest bottom, we hypothesise that the nest was not predated. Here we probably describe the first case of egg destruction by the Eurasian wren in Europe. [ABSTRACT FROM AUTHOR]

An influential period in avian life-cycles is the annual breeding season, when competition over suitable nesting sites and territories is a key factor that can determine fitness and distribution, especially for species that are highly selective in their nesting habitats. We analysed nest-site characteristics, breeding success and competitive interactions between two apex predator populations. Whereas the Short-toed Eagle Circaetus gallicus has nested in the Judean Foothills (Israel) for a long time, the Long-legged Buzzard Buteo rufinus has only invaded the nesting habitat of the Short-toed Eagle during their breeding season in the last two decades. These two recently sympatric species have similar nesting ecology and frequently use the same nests. They are therefore expected to compete over nesting sites and territories. We analysed interspecific interactions between these two species by combining information from comprehensive observational, experimental, GIS analysis and remote sensing data, deriving 65 variables to characterize the nest-sites used and the breeding success in 381 breeding attempts over four consecutive breeding seasons. To assess interspecific and intraspecific territorial behaviour and aggressiveness, stuffed Long-legged Buzzards and Short-toed Eagles were presented close to nests. Nest-site characteristics overlapped substantially between species, and Long-legged Buzzards occupied 21% of all Short-toed Eagle nests. Intraspecific aggression rates among Long-legged Buzzards were higher than their interspecific aggression rates with Short-toed Eagles and also higher than intraspecific aggression among Short-toed Eagles. Long-legged Buzzard and Short-toed Eagle breeding densities (1.59 ± 0.11 and 2.96 ± 0.11 pairs per 10 km2, respectively) are likely to be the highest across their respective breeding distributions, with a maximum productivity of 0.96 ± 0.01 and 0.56 ± 0.05 (young fledged/breeding pair) for Long-legged Buzzard and Short-toed Eagle, respectively. Intraspecific interactions among both species play an important role in determining their breeding success and the spatial distribution of nesting sites. Our results suggest that interspecific competition over nesting sites and territories between both species, and the potential dominance of Long-legged Buzzard, has both direct and indirect impacts on the spatial and demographic distribution of Short-toed Eagles due to the recent establishment of Long-legged Buzzard territories in the Judean breeding area. [ABSTRACT FROM AUTHOR]

Research on nest occupation and prey grabbing by saker falcon (Falco cherrug) on power lines in Vojvodina (Serbia) was done in the period from 1986 to 2004. During three specially analyzed periods, saker falcon took the nests of raven (Corvus corax) in 91% of a total of 22 cases of nest occupation, and those of hooded crow (Corvus corone cornix) in only 9%. Saker falcon regularly grabs prey from different birds that occasionally or constantly spend time around power lines [Kestrel (Falco tinnunculus), hobby (Falco subbuteo), hooded crow (Corvus corone cornix), jack-daw (Corvus monedula), marsh harrier (Circus aeruginosus), hen harrier (Circus cyaneus), buzzard (Buteo buteo), and raven (Corvus corax)]. One year a studied pair of saker falcons on a power line in Donji Srem, Serbia grabbed prey from five different species of birds. Out of a total of 40 cases of prey grabbing in the period from January to December, as much 70% of the grabbed prey was taken from kestrel (Falco tinnunculus). During the winter and early spring, prey was grabbed predominantly by males; after May, prey was sometimes grabbed by females as well. Most of the grabbed prey was common vole (Microtus arvalis).

Scavenging has been threatened with the declines of vultures. The Cinereous Vulture Aegypius monachus is predicted to be decline with mainly anthropogenic activities in Turkey, having the second largest population of the species in Europe. Earlier studies urgently recommended constituting a buffer zone in a spatial and temporal context for breeding areas of the species. For an effective buffer zone, land managers mostly used both the empirically revealed flight and stress distances between human activity and breeding individuals. Furthermore, various spatial and temporal factors could influence the disturbance level and reaction distances to human activity. Furthermore, reaction distances could affect the nesting strategies of the species as a disturbance indicator. Therefore, the main aim of this study is to determine the reaction distances as well as the significant spatial factors that influence those distances and to demonstrate the relationship between reaction distances and nest occupation. The study was carried out with the population of Cinereous Vultures in the Middle Sakarya Region in Northwest of Turkey. Based on 61 field observations, the average flight distance was 281.35 m, and stress distance was 467.53 m. The results also indicated that highly accessible and visible slopes located opposite the nest and concentrated in and/or around pathways/roads influenced the reaction distances of the breeding individuals significantly. Moreover, the reaction distances and roads are the primary factors for the decision of nest occupation in the study area. According to the study, 1084 m could be used as a radius for the inner buffer zone and the buffer zone was estimated as 369 ha. If it is not acceptable for economic reasons, at least 870 m should be used as a radius for the critical buffer zone. In conclusion, this study supports that the sensitivity of the Cinereous Vulture increases with the increase in accessibility/visibility of nest sites and those sensitivity levels may have affected the nest occupation of the species. [ABSTRACT FROM AUTHOR]

The effects of competition and risk of predation on secondary cavity breeders were examined between the 2008 and 2009 breeding seasons using an experimental design manipulating two nest entrance sizes (large entrances allowed Barn Owls ( Tyto alba) to enter, while the small entrances excluded them). During the 2009 breeding season, the entrance sizes of nest boxes were exchanged, so that if during one year a nest box in a particular location had a small entrance, the second year it had a large entrance and vice versa. Barn Owls and Eurasian Kestrels ( Falco tinnunculus) occupied 67.3 and 17.3%, respectively, of large entrance nest boxes. Significantly more Jackdaws ( Corvus monedula), House Sparrows ( Passer domesticus) and Scops Owls ( Otus scops) bred in nest boxes with small than with large entrances. After nest box entrance sizes were exchanged, Barn Owls and smaller species did not breed in the same nest boxes with the new entrance size. Jackdaws probably did not breed in large entrance nest boxes due both to exploitation competition (Barn Owls and Eurasian Kestrels occupied the majority of large entrance nest boxes), and may also have avoided empty nest boxes because of the risk of interference competition; whereas smaller species may have also avoided large entrance nest boxes due to risk of predation. [ABSTRACT FROM AUTHOR]