Dietary niche comparison of raptors in NE Iran, as an important zoogeographic zone

Abstract

Diet analysis is one of the most basic requirements for understanding species' ecological niches and determining their feeding relationships in an ecosystem. Pellets are common material for investigating diets. In this study, to investigate the diets and food niche overlap of coexisting raptors in NE Iran, a total of 344 pellets were collected during 2017–18. The pellets belonged to common buzzard (Buteo buteo), long-legged buzzard (Buteo rufinus), little owl (Athene noctua), common kestrel (Falco tinnunculus), golden eagle (Aquila chrysaetos), and Eurasian sparrowhawk (Accipiter nisus) from the Binalud protected area. Analysis of prey percent frequency showed that the pellets were predominantly composed of the remains of rodents, followed by birds and reptiles. The most frequently captured rodents were jirds (Meriones libycus and M. persicus), followed by a vole (Microtus arvalis). Although the raptors generally utilized small mammalian prey, they showed species-specific preferences and seasonal variations in the share of prey species. According to three niche overlap indices, the largest food overlaps were found between long-legged buzzard with common buzzard, and golden eagle with common buzzard. The smallest food overlap was found between little owl and golden eagle. Seasonal comparison for common buzzard, common kestrel and little owl showed that richness in the prey items was the highest in summer, followed by autumn. In addition to providing valuable information in terms of raptors' food habits and biodiversity, the results of this study can be leveraged in conservation and management programs.