Diet of the lesser kestrel Falco naumanni at post-breeding roosts in southern Albania

Abstract The lesser kestrel is an insectivorous and migratory falcon species, frequently using communal roosts in the post-breeding period in southern Europe. Using pellet analysis from two post-breeding roosting sites in southern Albania collected in August 2017, we identified 1539 prey items belonging to approximately 58 prey species, 20 families and 7 orders in 110 pellets from two sites. Invertebrates made up the major part of the diet spectrum (PNI = 99.8 %, PFI = 100 %). Invertebrate prey body size varied between 8 and 62 mm (mean 28.1 mm). Bush-crickets (Tettigoniidae) and locusts (Acrididae) were the most abundant and frequent prey groups (PNI = 33 % resp. 48.6 % and PFI = 97 % resp. 94 %). Within the bush-cricket family we could identify the species of genera Tettigonia, Decticus, Platycleis, Isophya and Metrioptera. The species of genera Calliptamus, Stenobothrus and Locusta belonged among the locust species identified in the food. Birds and mammals were found in pellets only occasionally. The prey composition was rather similar at both studied sites, while locusts (Acrididae) were more abundant at the Jorgucat site and bush-crickets (Tettigonioidea) at the Mollas site in the same time. Prey groups Scarabeidae beetles and other beetles (Coleoptera other) were more abundant and frequent at Mollas than at Jorgucat, and spiders were more frequent at Jorgucat. These results suggest that the high abundance of orthopterans and beetles in the food supply in certain localities is the main reason for selection and stable occupancy of these massive communal roosting sites by lesser kestrels in Albania.