Habitat use by short-toed eagles Circaetus gallicus and their reptilian prey during the breeding season in Dadia Forest (north-eastern Greece)

SUMMARY The area surrounding and including Dadia Forest, north-eastern Greece, is well known for its diversity of breeding raptors, including many species of conservation concern. Dadia Forest has been exploited by humans for many centuries, but more recent social and economic changes have stimulated proposals that the forest should be subject to habitat management to protect the fauna of the region. We examined the distribution of reptiles over nine different habitat types with a view to assessing the importance of these habitats for foraging by short-toed eagles Circaetus gallicus. In addition, data on the diet of the species were collected from direct observations at nests. The short-toed eagle relies heavily on snakes for food. The most important prey species was the grass snake Nutrix natrix, although the Montpellier snake Malpolon monspessulunus and large whip snake Coluber jugularis also featured prominently as prey items at certain nests. Montpellier snakes and large whip snakes were distributed across all habitat types, but grass snakes were concentrated in areas of mainly intensive, but also non-intensive, cultivation. Analysis showed that short-toed eagles concentrated their foraging efforts in three habitat types: intensive and non-intensive cultivation and grasslands. Grass snakes were abundant on cultivated land but relatively scarce on grassland. Forested areas were largely avoided by foraging eagles. The data show that for the short-toed eagle the distribution and abundance of prey items on the ground does not reflect food availability. The possible effect of changes in habitat management on the short-toed eagle population in Dadia is discussed, in particular the establishment of exclusion zones that could result in progressive canopy closure.