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Bonelli’s Eagle Aquila fasciata is one of the rarest birds of prey in Europe, where it has suffered a significant decline in recent decades. We present information on the home‐ranges and spatial parameters of 18 Bonelli’s Eagles radiotracked in 2002–2006 in Catalonia (northeast Spain) and describe the home‐range probability kernel, distances moved, breeding area eccentricity, territorial overlap,...
Survival typically contributes most to population trends in long‐lived birds and its accurate estimation is therefore vital for population management and conservation. We evaluated the effects of age, territoriality and reproduction on survival in Bonelli’s Eagle Aquila fasciata through multistate capture‐mark‐recapture analyses on a long‐term dataset. Monitoring was carried out in southeast France...
The effect of changing climatic conditions on wild populations has been the subject of much recent research. Most attention has been on the direct effects of climate changes on species of lower trophic levels and on the negative consequences of climate change. However, a deeper understanding of how climate change affects apex predators is vital, as they are keystone species that have a disproportionate...
Diet analyses are central to the study of avian trophic ecology, and stable isotope analyses have made an increasing contribution in the last two decades. Few isotopic studies have assessed the diet of raptor species, which are more frequently analysed by conventional diet methods such as pellet analysis. In this study, we compare prey consumption estimates of nestling Bonelli's Eagles Aquila fasciata...
The morph ratio distribution in polymorphic species often varies clinally, with a gradual change in morph ratios across the distributional range of the species. In polymorphic bird populations, clinal variation is rarely quantified. We describe a cline in the morph ratios of Black Sparrowhawks across South Africa, which is principally driven by a higher ratio of dark morph birds in the newly colonized...
There are serious concerns about the environmental and ecological degradation caused by modern agriculture and its impact on animal populations. There is therefore a need to assess the reproductive performance of free‐living animals in agricultural landscapes. We undertook a 4‐year study on the reproductive biology of Eurasian Kestrel Falco tinnunculus in the Parma district of Italy. Kestrels breeding...
Gaps in our knowledge of the geographical distribution of species represent a fundamental challenge to biogeographers and conservation biologists alike, and are particularly pervasive in the tropics. Here we highlight the case of the Rufous‐thighed Kite Harpagus diodon, a South American raptor commonly mapped as resident across half the continent. Recent observations at migration watch points have...
Migration is a significant event in the annual cycle of many avian species. During migration birds face many challenges, including unfamiliar foraging and refuge habitats, resulting in a much higher rate of mortality during migration than during other seasons of the year. Weather may significantly affect a bird's decision to initiate migration, the course and pace of migration, and its survival during...
Body size strongly influences fitness, with larger individuals benefiting in terms of both greater productivity and survivorship; for reverse sexual size dimorphic (RSD) species, this relationship may be more complex. We examined the selection pressures acting on body size in male and female Merlins Falco columbarius to assess whether larger or smaller individuals of this RSD species were favoured...
Migrating juvenile birds rely on endogenous information in choosing the direction in which to fly, but such input may be overridden by social interactions with experienced individuals. We tagged seven juvenile Short‐toed Eagles Circaetus gallicus with GPS transmitters in southern Italy. This trans‐Saharan migrant flies mainly by soaring and is therefore not well adapted to performing long water crossings...
Predators will often respond to reductions in preferred prey by switching to alternative prey resources. However, this may not apply to all alternative prey groups in patchy landscapes. We investigated the demographic and aggregative numerical and functional responses of Common Buzzards Buteo buteo in relation to variations in prey abundance on a moor managed for Red Grouse Lagopus lagopus scotica...
Flight behaviour characteristics such as flight altitude and avoidance behaviour determine the species‐specific collision risk of birds with wind turbines. However, traditional observational methods exhibit limited positional accuracy. High‐resolution GPS telemetry represents a promising method to overcome this drawback. In this study, we used three‐dimensional GPS tracking data including high‐accuracy...
Diet differences between the sexes and ages have often been recorded for bird species. Many raptor species show extreme sexual size dimorphism, with females often considerably larger than the males and these differences may be reflected in their diets. Diet studies in raptors most frequently focus on analysing prey remains or pellets collected at nest‐sites. These methods are subsequently limited...
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