Organisms aim to maximize their energy intake while minimizing the energy expended during foraging. However, as the environmental conditions vary in space and time, they have to adjust foraging strategies accordingly. The Eurasian Goshawk (Astur gentilis) is an iconic bird of prey widely regarded as a sentinel species of valuable old-growth forests. However, as a flexible raptor, it also thrives in other landscape types, such as agricultural and urban environments. We used GPS telemetry to track the movements of 13 male Goshawks breeding in the largest remaining temperate lowland old-growth forest in Europe, the Białowieża Forest, and examined their diet and reproductive success. We detected a variety of foraging strategies among individuals, ranging from predominantly forest-based hunting to regular excursions outside the forest to forage in farmland, villages, and towns. These behavioural responses were not consistently associated with nest site locations and consequently we found no relationship between home range size and either forest quality in the nest surroundings or proximity to alternative foraging habitats. Strikingly, several individuals breeding deep within the forest routinely travelled up to 20 km to hunt feral pigeons in a town, suggesting that the high abundance, accessibility, and predictability of optimal prey in urban environments shape the foraging behaviour of raptors even within primeval forests. We conclude that, rather than a single optimal foraging strategy, several equally profitable strategies exist for Goshawks breeding in old-growth forests.

Raptor populations in Africa are rapidly declining, yet causes of mortality are insufficiently known for most resident species understudied beyond poisoning. This study aimed to investigate the causes of raptor mortality on the African continent. We compiled 1012 mortality records from 43 raptor species tracked with GPS transmitters in Africa between 2003 and 2026 to identify the main causes of mortality, estimate the relative contribution of anthropogenic vs natural causes of mortality, and the factors affecting mortality. Human-induced mortality accounted for 58.8% of known mortality in migratory raptors (n = 233) and 74.3% in non-migratory raptors (n = 241). The main causes of known mortality were direct killing (24.4% of 474 records), poisoning (23.6%), and electrocution (10.1%). Predatory raptors were at higher risk of direct killing than vultures, had higher risk in urbanised than rural landscapes, for non-migrants compared to migrants, and during the non-breeding season compared to the breeding and migration seasons. Vultures had a higher risk of poisoning among adults compared to immatures and in more rural/protected areas relative to urbanised areas. Among poisoned vultures (n = 103), 40.2% were poisoned intentionally. Electrocution occurred at similar rates in vultures and predatory raptors, and more frequently with more urbanisation. The proportion of tracked birds for which cause of mortality could be identified increased over time but remained lower for non-migrants compared to migrants. Our results show the predominantly anthropogenic origin of raptor mortality in Africa, stressing the need for stronger conservation actions directed against direct killing, poisoning, and electrocution.

Spatial ecology of species is determined by the interplay of various social and demographic factors. Variation in utilisation of space may also reduce the conflict between individuals competing for the same resources. We simultaneously evaluated the effects of sex, territoriality and reproductive performance on the space use of the Eurasian goshawk, Accipiter gentilis, by analysing the home range sizes of 25 individuals across various stages of the annual cycle for up to 7 years. The mean annual home range (90% autocorrelated kernel density estimate) of territorial goshawks was slightly smaller than that of non-territorial hawks, and the ranges of successful birds tended to be smaller than those of non-successful territorial goshawks. The median home range of territorial females (295 km2) was five times larger than that of males (58 km2). While the home ranges of males overlapped by 89-100% with those of females, only 7-14% of females' ranges were utilised by their male counterparts. The home ranges of territorial females gradually increased after the incubation stage, and their fidelity to nest sites weakened. Males maintained their association with their nest sites throughout the year. These sex-specific differences may be attributed to distinct strategies, with males acting as territory holders and females exploring potential mates and nest sites, or to the reduction of competition between partners. The findings underscore the significance of long-term tracking across annual cycles in determining annual home ranges and show how complex space use patterns are in sedentary dietary specialists under seasonally varying food resources and intra- and extrapair competition.

Forest characteristics influence species at macrohabitat and microhabitat levels, but the mechanisms of these associations are still poorly understood. We used GPS-tracking to identify key ecological links shaping the foraging habitat selection of the Eurasian Goshawks (Astur gentilis) in forests and thereby evaluated the potential of the species to indicate high conservation-value forests. We tracked 25 Goshawks for up to six years in a 5300 km2 study area in Estonia (north-eastern Europe) and followed the Resource Selection Function approach to detect seasonal and sex-specific variations in habitat selection, using a series of variables on forest structure heterogeneity, composition, and conservation. Goshawks exhibited distinct preferences for mature, structurally complex, high conservation-value forests with abundant lying deadwood and proximity to water bodies. Females favored older, denser forests closer to edges, while males demonstrated greater flexibility, utilizing a broader range of forest types. Seasonal variations were also observed, with coniferous forests becoming more critical for females during defoliated periods, while males showed a stronger preference for deciduous forests year-round. By elucidating the habitat preferences of the Goshawk as an indicator species, our study highlights the importance of maintaining diverse forests. Our findings also inform potential conservation strategies for preserving high-value forest habitats.

The immature period is an important stage in the life histories of animals, influencing their subsequent development and future experiences. This stage is particularly pronounced in long-maturing raptors. In this study, we examined individual ranging areas at breeding and wintering grounds of the vulnerable Clanga clanga (Greater Spotted Eagle) and their hybrids with C. pomarina (Lesser Spotted Eagle) from their primary European Union populations in Poland and Estonia. We analyzed GPS tracking data from 26 individuals (including 11 hybrids) tagged between 2008 and 2022. Our results revealed a reduction in individual ranging areas at both breeding and wintering grounds as the birds matured. With increasing age, C. clanga arrived earlier at future breeding sites, likely to synchronize with breeding adults and enhance their ability to compete for territories and mates. As they aged, immature eagles also extended their stay at breeding grounds. Some individuals limited their ranging areas as early as their 4th or 5th calendar year, indicating the onset of site fidelity, whereas others continued wide-ranging movements into their 7th year. Males, in particular, exhibited philopatry and frequently visited nests of established pairs within their natal population prior to their own recruitment as breeders. Immatures were first observed at nests between their 3rd and 7th calendar years, but confirmed breeding typically occurred later, between their 8th and 10th calendar years. Eight individuals (7 males) were found breeding at an average distance of 8.1 +/- 7.3 km from their natal nests. No behavioral differences were observed between C. clanga and their hybrids. Our findings illustrate the slow maturation and prolonged preparation for breeding in this species and its hybrids. These results may inform population dynamics modeling and aid in the conservation of these vulnerable species. We tracked GPS-tagged immature Clanga clanga (Greater Spotted Eagle), a long-lived, slow life-history species, and their hybrids with C. pomarina (Lesser Spotted Eagle) to investigate behavioral changes during the adolescent stage. We found that the individual ranging areas at both wintering and breeding grounds decreased with age. As the eagles matured, they arrived at breeding sites progressively earlier. Eagles returned close to natal site and gradually restricted their space use, typically between the 4th and 7th calendar year. Recruitment into the breeding population occurred even later. Our study highlights the importance of the maturity period in long-lived birds, such as the species studied here, for later recruitment to breeding population. We also emphasize the prolonged and complex nature of maturation and recruitment, and, consequently, the vital importance of each individual in the conservation of globally vulnerable species. El per & iacute;odo inmaduro es una etapa importante en la historia de vida de los animales, que influye en su desarrollo posterior y en sus futuras experiencias. Esta etapa es particularmente marcada en rapaces de maduraci & oacute;n lenta. En este estudio, examinamos las & aacute;reas de rango individual en las zonas de reproducci & oacute;n e invernada de la especie vulnerable Clanga clanga y de sus h & iacute;bridos C. clanga x pomarina provenientes de sus principales poblaciones de la Uni & oacute;n Europea en Polonia y Estonia. Analizamos datos de rastreo por GPS de 26 individuos (incluidos 11 h & iacute;bridos) marcados entre 2008 y 2022. Nuestros resultados revelaron una reducci & oacute;n en las & aacute;reas de rango individual tanto en las zonas de reproducci & oacute;n como de invernada a medida que las aves maduraban. Con el aumento de la edad, C. clanga lleg & oacute; m & aacute;s temprano a los futuros sitios de reproducci & oacute;n, probablemente para sincronizarse con los adultos reproductores y mejorar su capacidad de competir por territorios y parejas. A medida que envejec & iacute;an, las & aacute;guilas inmaduras tambi & eacute;n extendieron su permanencia en las & aacute;reas de reproducci & oacute;n. Algunos individuos limitaron sus & aacute;reas de rango ya en su cuarto o quinto a & ntilde;o calendario, lo que indica el inicio de la fidelidad al sitio, mientras que otros continuaron con movimientos de amplio rango hasta su s & eacute;ptimo a & ntilde;o. Los machos, en particular, exhibieron filopatr & iacute;a y visitaron con frecuencia los nidos de parejas establecidas dentro de su poblaci & oacute;n natal antes de su propio reclutamiento como reproductores. Las aves inmaduras fueron observadas por primera vez en nidos entre su tercer y s & eacute;ptimo a & ntilde;o calendario, pero la reproducci & oacute;n confirmada ocurri & oacute; t & iacute;picamente m & aacute;s tarde, entre su octavo y d & eacute;cimo a & ntilde;o calendario. Se encontr & oacute; que ocho individuos (7 machos) se reprodujeron a una distancia promedio de 8,1 +/- 7,3 km de sus nidos natales. No se observaron diferencias de comportamiento entre C. clanga y sus h & iacute;bridos. Nuestros hallazgos ilustran la lenta maduraci & oacute;n y la preparaci & oacute;n prolongada para la reproducci & oacute;n en esta especie y sus h & iacute;bridos. Estos resultados pueden contribuir a los modelos de din & aacute;mica poblacional y a la conservaci & oacute;n de estas especies vulnerables.

Adult survival and turnover rates are often estimated in long-lived species as the primary drivers of population dynamics. Various methods have been used, yet comparison of estimation methods is seldom undertaken. To address this gap, we used colour-ringing across different age groups, as well as GPS-tracking and genetic analysis of shed feathers, to estimate these critical parameters in a population of a medium-sized bird of prey, the Lesser Spotted Eagle. According to the colour-ringing data, the apparent survival during the first year of life (0.21) was more than four times lower than that of birds older than one year (0.88); the GPS-tracking (0.84) and genetic analysis (0.81) yielded similar survival estimates. However, population turnover rates derived from genetic feather analysis (0.17-0.43) exceeded expectations based on apparent survival estimates, as well as those derived from colour-rings (0.05-0.17) and GPS-tracking (0.05-0.08). Notably, all markers indicated high site fidelity among adult eagles, with breeding dispersal events being infrequent. Our findings underscore the utility of various methods for estimating apparent survival, though the ecological characteristics of the species may influence the efficacy of each method. However, estimates of population turnover rates were notably influenced by the choice of method and should be interpreted cautiously before recommending management actions.

Red Kites Milvus milvus and Black Kites M. migrans, two raptor species, occasionally hybridise in Europe. Yet the ecology of hybrids is virtually unknown. Here, I describe migration patterns of a hybrid offspring of the two species. In 2022, a juvenile hybrid male was GPS-tracked from its nest site in Estonia to southern Greece. Between 23 August and 18 September, the hybrid covered 3213 km and made three short stops lasting 1-3 days. The mean daily flight distance was 128 km (21.5-283 km). The route used by the hybrid is a minor flyway for both parental species. The quantitative migration patterns were more consistent with those of the Black Kite but were within the wide range of variation among Red Kites.

Global agricultural landscapes are witnessing a concerning decline in biodiversity, and this trend is predicted to persist. To safeguard these biodiversity-rich areas, it is crucial to pinpoint hotspots effectively. In doing so, we used various species of avian predators as suitable sentinel animals due to their mobility and dependence on prey diversity and abundance. Between 2019 and 2021, we tracked 62 individuals from four bird of prey species using GPS loggers in Estonian farmland. Dividing the study area into 50 m grids and overlaying them with tracked individuals' locations enabled us to differentiate between hotspots of their activity and control sites. We conducted surveys on amphibian, bird, small mammal and plant abundance and diversity to determine if avian predator activity hotspots correlated with overall biodiversity. Our findings revealed significantly higher diversity and abundance in the surveyed groups within activity hotspots compared to control sites. These hotspots continued to be frequently used by raptors in the subsequent year, albeit not two years later. In conclusion, multispecies GPS telemetry of avian predators emerges as an objective, dependable and spatially accurate biodiversity indicator. With the accumulation of movement data, we anticipate increased interest and adoption of this approach in biodiversity monitoring.

Human conflicts can have impacts on wildlife, from direct mortality and environmental damage to the displacement of people, changing institutional dynamics and altering economies.1,2,3 Extreme anthropogenic disturbances related to conflict may act as a barrier to migrating birds and increase the energetic costs of migration.4 On February 24th, 2022, the Russian Federation invaded Ukraine, with targeted attacks on Kyiv and the eastern regions.5 By March 3rd, when the first of 19 tagged Greater Spotted Eagles entered Ukraine on migration, the conflict had spread to most major cities, including parts of western Ukraine.6 We quantified how conflict impacted the migratory behavior of this species using GPS tracks and conflict data from the Armed Conflict Location and Event Data (ACLED) project7,8 in a quasi-experimental before-after control-impact design, accounting for meteorological conditions. Migrating eagles were exposed to conflict events along their migration through Ukraine and exhibited different behavior compared with previous years, using fewer stopover sites and making large route deviations. This delayed their arrival to the breeding grounds and likely increased the energetic cost of migration, with sublethal fitness effects. Our findings provide a rare window into how human conflicts affect animal behavior and highlight the potential impacts of exposure to conflict events or other extreme anthropogenic disturbances on wildlife.

Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of species worldwide. Tracking technologies can be an important tool to investigate temporal and spatial patterns of bird mortality as well as their drivers. We compiled 1704 mortality records from tracking studies across the African-Eurasian flyway for 45 species, including raptors, storks, and cranes, covering the period from 2003 to 2021. Our results show a higher frequency of human-induced causes of mortality than natural causes across taxonomic groups, geographical areas, and age classes. Moreover, we found that the frequency of human-induced mortality remained stable over the study period. From the human-induced mortality events with a known cause (n = 637), three main causes were identified: electrocution (40.5 %), illegal killing (21.7 %), and poisoning (16.3 %). Additionally, combined energy infrastructure-related mortality (i.e., electrocution, power line collision, and wind-farm collision) represented 49 % of all human-induced mortality events. Using a random forest model, the main predictors of human-induced mortality were found to be taxonomic group, geographic location (latitude and longitude), and human footprint index value at the location of mortality. Despite conservation efforts, human drivers of bird mortality in the African-Eurasian flyway do not appear to have declined over the last 15 years for the studied group of species. Results suggest that stronger conservation actions to address these threats across the flyway can reduce their impacts on species. In particular, projected future development of energy infrastructure is a representative example where application of planning, operation, and mitigation measures can enhance bird conservation.

Summary Detecting factors causing the decline of wildlife populations provides essential knowledge for their effective conservation. Populations of Black Stork Ciconia nigra are decreasing in northern Europe; however, there are no detailed analyses of its survival, which frequently is a key demographic parameter affecting population dynamics in long-lived species. We used long-term data from re-sighted colour-ringed birds and satellite-tracked birds to estimate age- and sex-specific survival in a rapidly declining Black Stork population in the Baltic region at the northern end of the European range. Apparent survival (0.89) among colour-ringed birds older than one year was not significantly different from the previously reported estimates in Central Europe and the estimated real survival of GPS-tracked birds (0.77). However, the apparent survival of first-year (1y) birds was only 0.04, which is remarkably lower than earlier estimates in Central Europe. The real survival of GPS-tracked 1y birds was somewhat higher (0.11), but still much lower than estimates in other long-lived species. Apparent survival was three times lower in 1y females (0.013) than 1y males (0.045); this could be explained in part by a higher mean natal dispersal of females (189.1 km), compared with that of males (72.0 km), as well as by sex-specific mortality due to poor foraging conditions. There were no significant differences in apparent survival between the male and female storks older than one year. To better address the population decline, further research is needed to determine the factors causing low survival in young Black Storks, including the roles of food availability and climate change.

Abstract The northern hawk owl is a real irruptive species that respond to irregular changes in the food supply. When prey levels are adequate, it breeds and winters within northern forests. Decreased prey availability can start winter invasions, the timing and magnitude of which are the subject of this study. Mainly the citizen data were extracted from the national bird websites to obtain data on the number of northern hawk owls observed in 2010–22. This paper demonstrates that through citizen data large amounts of information can be collected over wide areas, entire Europe in this case. From Finland to Poland and Czechia the invasions years were very similar, 2013–14, 2017–18 and 2021–22 but in Sweden and Norway three clear irruption years were a year or two before. In Denmark, the clear invasions years were 2013–14, 2016–17 and 2019–20 but Poland, peak years were not at all as clear as in the other countries. The invasions started earliest in Finland in September and peaked in November. In Estonia and Latvia peaks occurred from November to January. In Poland, irruption peaked a month later in December but continued until April like in Finland, Estonia and Latvia. The origin of the irrupting owls in the region has been debated. In Norway, authors are convinced that owls originate from Fennoscandia but this paper indicates that mass invasions have to originate from northern Russia. However, only in Denmark there was one Russian northern hawk owl ring recovery. Further ring recoveries and preferably GPS tagging and satellite tracking of the northern hawk owls are awaited to have a better picture of invasion movements and future conservation needs.

Monitoring of biodiversity in expanding urban areas is an essential part of wildlife conservation. There is evidence that raptors, such as Northern Goshawks (Accipiter gentilis), are effective bioindicator species in urban areas, however, their relationship with other bird populations is not clearly established. We asked whether activity patterns of Goshawks are a reliable indicator of wintering bird abundance and diversity in urban ecosystems. We tracked the movement of eight GPS-tagged Goshawks in the city of Tartu (Estonia) and analysed the numbers and diversity of birds in the same area using direct mapping and occasional data obtained from birdwatchers. The direct mapping approach revealed that the number of birds and avian species richness were higher in Goshawk activity hotspots than at random sites in 2022, however, no such differences were detected in 2023. Analysis of occasional citizen-collected data showed no effect of avian abundance nor species richness on the distribution of Goshawk activity. These results suggested that the movements of Goshawks may indicate the abundance and diversity of its prey, however, this relationship depends on the detection methodology. Hence, raptors are a promising bioindicator in urban environments, but results should be interpreted with caution, particularly when using citizen-collected data.

Capsule: Shed feathers can be used for the field identification of the Greater Spotted Eagle Clanga clanga and Lesser Spotted Eagle Clanga pomarina, but identification of hybrids is problematic. Aims: To provide an easy method for distinguishing the shed flight feathers of the Greater Spotted Eagle, Lesser Spotted Eagle, and their hybrids. Methods: We examined seven morphological characteristics and developed multinomial logistic regression models to aid in identification of feathers. Results: The most informative feature was the relative feather length. Barring improved the identification of tail feathers, secondaries, and proximal primaries. Feathers of Lesser Spotted Eagles were significantly shorter and more barred than those of Greater Spotted Eagles. Feathers of hybrids were also highly barred but had an intermediate length. The length from the tip to notch, width of the notch, and specific colouration patterns were also included in the best models for specific feather types. The combination of these characteristics resulted in identification accuracies of 89-97% for Lesser Spotted Eagle feathers and 80-100% for Greater Spotted Eagle feathers. However, all F1-hybrids were incorrectly identified as Greater Spotted or Lesser Spotted Eagles. Conclusion: Shed feathers could have potential for the non-invasive field identification of spotted eagle species at nest sites. However, the identification of hybrids based on feathers is difficult due to substantial morphological variation and overlap with parent species.

Our study aims to increase the understanding about the impacts of potential drivers of pollen richness by using a pollen-vegetation modelling approach. We used the Sutton-Prentice dispersal model implemented in the HUMPOL software suite to explore the effects of factors commonly associated with pollen richness: vegetation diversity (plant richness and evenness), land-cover characteristics (patch richness, evenness and size, and basin size) and pollen-related parameters (productivity and fall speed). The impact of the factors was tested using modelling scenarios involving all combinations of the included factors and their values. All tested factors had a statistically significant impact on modelled pollen richness. Pollen-type based plant richness was the dominant determinant of pollen richness; however, pollen productivity became co-dominant at higher plant richness levels, effectively limiting the detection of species with low pollen productivity. The fall speed of pollen and sedimentary basin size had moderate impact, but gained importance in simulations with elevated plant richness. In patchy land-cover, patch richness was the most significant determinant of pollen richness, while patch evenness and size were the least important factors. Our modelling approach provides insights into the significance of common factors in determining pollen richness and its connection to plant diversity, as well as a theoretical basis for understanding the substantial variation among earlier empirical pollen-plant richness studies. The estimation of plant richness from pollen richness in past vegetation diversity studies could be improved by the separation of taxa with low and high pollen productivity and an awareness of the pollen source area.

Characterizing the genetic diversity and structure of populations is essential for understanding their evolutionary history and planning species conservation. The lesser spotted eagle (Clanga pomarina) is a large migratory raptor with a relatively small breeding range concentrated in Eastern Europe. We evaluated the level of genetic diversity and population structuring by estimating the length diversity of 23 microsatellite markers in 306 individuals and sequencing 473 nucleotides from the mitochondrial pseudo-control region in 265 individuals across the distribution range. The microsatellite data suggested shallow differentiation between geographical regions and moderate genetic diversity across the range; no recent population bottlenecks were detected. Mitochondrial diversity was relatively low; however, high values were recorded at the southern edge of the distribution range. This, in combination with the star-like distribution of mitochondrial haplotypes, suggests the expansion of the European population from a single (Balkan) refugium during the late Pleistocene or early Holocene after the glacial population bottleneck. However, the Caucasian population may have survived in a separate refugium. We conclude that the lack of clear population structuring and ongoing gene flow across Europe support the treatment of the geographically restricted global population of the lesser spotted eagle as a single evolutionary and conservation unit.

Biodiversity is often highest at ecotones. However, edge effects vary among species and the spatial extent has rarely been quantified. Rodents form an important part of the food chain and thus are keystones of the ecosystem. We measured the species richness and abundance of rodents at ecotones between forests and three types of open agricultural biotopes (grasslands, rapeseed fields, and cereal fields) along perpendicular transects. The species richness and relative abundance of rodents were highest at the forest/grassland ecotone where the densities of the yellow-necked mouse (Apodemus flavicollis) and the striped field mouse (A. agrarius) were highest. The highest density of the forest-dwelling bank vole (Myodes glareolus) was recorded next to grasslands; however, the abundance of this species increased towards the forest interior. The positive edge effect of ecotones on species richness and total abundance did not exceed 10 m. Our results suggest that maintaining narrow grasslands at the margins of crop fields would strengthen rodent communities at ecotones as well as in adjacent forests.

Species coexist only when occupying different ecological niches. We evaluated habitat and trophic niches in two recently diverged hybridizing avian apex predators, the declining Greater Spotted Eagle Clanga clanga (mainly found in contracting wetlands) and the more numerous Lesser Spotted Eagle Clanga pomarina (inhabiting mosaic farmlands). We tracked 24 Spotted Eagles, including interspecific hybrids, by GPS to estimate the home-range size, land use composition and landscape structure in sympatric populations. In addition to information for landscape utilization, data for diet composition were evaluated. Home-ranges of the two species were similar in size and open foraging habitats consisted mostly of agricultural landscape. However, landscape utilization of the Greater Spotted Eagle was largely driven by the composition of land-use types, whereas the Lesser Spotted Eagle was mostly influenced by structural components of the landscape. Farmland-dwelling voles accounted for the bulk of the diet in both species; however, subdominant prey classes differed. Hybrids exhibited intermediate or mixed features of home-ranges and diets. Our results provide evidence for reduced niche partitioning and potential competition between the two Spotted Eagles, which may have been reinforced by anthropogenic habitat alteration. A closer examination of movement patterns revealed previously overlooked differences between closely related species with respect to landscape utilization strategies.

Citizen science is increasingly contributing to ecology and conservation research, mostly by the extensive collection of field data. Although webcams attract numerous observers, they have been underused in this respect. We used prey delivery records deposited by citizen scientists in an internet forum linked to webcams to explore the diet composition and food provisioning in a forest-dwelling raptor of conservation concern, the Lesser Spotted Eagle (Clanga pomarina). Four pairs were studied throughout the breeding season. Most of the identified prey items were mammals (62.1%), followed by frogs (31.2%), birds (6.6%) and fish (0.1%). Among mammals, voles accounted for 84.6%, moles 12.1%, water voles 2.4% and weasels 0.4%. Frogs were the most frequently detected prey item in the spring, with a slight increase towards the end of the season, the proportion of mammals increased during the breeding season, and birds were hunted mostly in the middle of the breeding season. However, exact temporal patterns differed between nests. The food delivery rate of males increased over time but decreased somewhat before fledging the young. Females started hunting in mid-summer and their rapidly increasing effort compensated for a reduced male hunting intensity. The data collected by citizen scientists via webcams reflected the general patterns detected in earlier studies, supporting the reliability of crowd-sourced web-based data collection in avian foraging ecology.

Context Small woody features (SWF; tree lines and small woods) in agricultural landscapes provide a substitute for forest conditions for a wide range of species and a suitable edge habitat for ecotone species. The importance of SWF for biodiversity is usually inferred from presence or abundance data for small animals. Although large animals, due to their lower density are less likely to be attributed with SWF, they may depend on these areas to effectively utilize the agricultural landscape matrix. Objectives We followed movements of three avian predator species (northern goshawk, common buzzard, and lesser spotted eagle) in the breeding and post-breeding season to assess their dependence on SWF in agricultural landscapes and to determine the characteristics of woods influencing each species. Methods We compared time spent flying and perching, where perching sites were classified as open space, forest interior, forest edge, and SWF. Next, the relative importance of SWF and forest edges, as well as specific characteristics of each habitat, were evaluated using resource selection functions. Results All species spent most of the daytime perching, and preferentially utilized SWF and forest edges. Buzzards and eagles were not influenced by the characteristics of SWF, but goshawks preferred relatively large, dense patches. Conclusions We conclude that SWF are crucial for exploitation of agricultural landscapes by avian predators by providing suitable perching sites for foraging. We also detected variation in the quality of perching sites, suggesting that for some species (like the goshawk), artificial perching sites cannot compensate for a lack of SWF.