Tail pattern variation in the Black Wheatear (Oenanthe leucura)

Delayed plumage maturation occurs in birds when subadult plumage is retained until after the first breeding season. We analysed data from 114 Black Wheatears (Oenanthe leucura), which were trapped during 2014–2016 in southeastern Spain, to explore whether biometric measurements, and more specifically tail pattern, differed among age and sex classes, and whether there was a relationship between tail pattern and delayed plumage maturation. Males and adults were heavier and had longer wings and tails than females and juveniles, respectively. Adult birds had longer terminal black tail bars than juveniles, which suggests a potential dominance-signalling function for the tail pattern. Further research is needed to investigate the relationship between these traits and sexual selection and dominance in Black Wheatear.