Trophic niche partitioning between two Rock Nuthatches (Sitta tephronota & Sitta neumayer) in a contact zone in Iran

摘要: Two sympatric nuthatch species, Sitta tephronota and S. neumayer, provided the exemplar case of character displacement when term was coined. The two species are quite similar morphologically but have diverged from one another in sympatry, presumably because competition-driven selection favoring partitioning food resources. However, actual diet has never been shown. Here, we report dietary composition by analyzing items recovered gastrointestinal tract. We found that S. tephronata fed predominantly on Coleopterans, Hemipterans Orthopterans with most important seed plants taken being Amygdalus lycioides, Ficus carica Fabaceae, whereas, S. neumayer mainly Lepidopteran, A. lycioides, Fabaceae Tritium aestivum as taken. To determine whether partition prey into different sizes, examined mostly abundant insect preys (Hemipterans Coleopterans) measured head length for mandible size Coleopterans proxies body size. a significant relationship between bird size, S. tephronata, which is larger, captured larger bugs beetles. also ability each to crack seeds hardness, finding takes harder than S. neumayer. Analyses trophic niche breadth overlap showed (1) wider S. tephronata; (2) overall considerably high (3) frequently consumed insects low, suggesting may be resources conclude relative an axis driven associated traits, allowing stable coexistence species.