NICHE SEGREGATION, BEHAVIOURAL DIFFERENCES, AND RELATION TO MORPHOLOGY IN TWO IRANIAN SYNTOPIC WHEATEARS : THE NORTHERN WHEATEAR OENANTHE OENANTHE LIBANOTICA AND MOURNING WHEATEAR O. LUGENS PERSICA

This study aims to test the hypothesis that the ecological segregation of two syntopic species of wheatear in a semi-desert area is associated with morphological differences that may be related to eco-ethological traits. The distribution areas of these two species, the northern wheatear Oenanthe oenanthe libanotica and the mourning wheatear O. lugens persica, overlap in the Zagros Mountain in central Iran, where the species are close to their respective distributional limits. We studied the niche segregation of these two syntopic birds by measuring their behaviour, foraging techniques, movement patterns, and habitat variables (vegetation, mineral substrate, and geomorphological features). Body dimensions were measured on museum skins. These two species differ in a number of morphological aspects that are mainly related to foraging behaviour and movement patterns. These differences, also mentioned in the literature in other chat-like species, seem to correspond to a niche segregation that may reduce interspecific competition.