The Function of Stones in Nest Building: The Case of Black Wheatear (Oenanthe Leucura) revisited

Black Wheatears ( Oenanthe leucura) transport to breeding territories, including the nest, a large number of stones. Currently, there is negative evidence that stones serve for nest support, thermoregulation, weather protection or anti-predation, but in males, this behaviour appears to represent a form of post-mating display. This ‘sexual selection’ hypothesis, however, does not explain why females also carry stones, and why many stones are associated with the nest. We examined stone distribution and morphology in 277 abandoned nests of Black Wheatears from an arid area of southeastern Spain. Nests were built on the ground (14.4%), or in cracks (7.2%), cavities (54.6%) and ledges (23.8%) a…