Sex identification of Eurasian Scops Owl Otus scops using morphometric analysis.

The Eurasian Scops Owl Otus scops is a migratory owl whose population is declining throughout a large part of its breeding range, due to intensification of farming practices and land-use changes. For this reason, it is considered Europe’s most threatened owl species. Scops Owl is one of several raptor species that are difficult to sex, due to limited morphological differences between the sexes. A reliable method of sexing Scops Owls through biometric measurements would facilitate the study of their sex-related survival, movements and behaviour characteristics, improving their conservation management. In the current study, we developed a cost-effective and accurate method of sexing Scops Owls, based on discriminant analysis of morphometrics. A sample of 105 birds were captured, sexed using genetic methods and had biometric measures taken. A generalised linear model was built to evaluate the biometric measures that are statistically linked to sex. The best model selected three variables: wing length, tail length and weight. The results of the model were used to derive model scores, and the probability of male and female to be correctly identified was predicted. The discriminant function provides an accurate method of sexing Scops Owls in the hand.