Détermination, par la biométrie, du sexe des poussins chez deux espèces de rapaces Circaetus gallicus et Buteo buteo

International audienceNestling sexing by biometric and molecular analysis in two diurnal raptors. The following data were collected during a long term study in France of the Common Buzzard Buteo buteo and the Short-toed Eagle Circaetus gallicus. Even though females of these two species are significantly larger than males, biometric parameters show substantial overlaps between sexes, so that in-hand sexing from morphometrics alone can be hazardous. Therefore, we have been looking for a reliable method of sexing nestlings, based on discriminant analysis of measurements, computed between groups of DNA determined males and females. In this paper, we give simple (linear) functions of a few parameters, allowing the prediction of the sex of a good proportion of the juveniles: Roughly 85% of Short-toed Eagle nestlings, older than 40 days (wing-length > 170mm), and 90% of Common Buzzard nestlings, from the age of 4 weeks (wing-length > 205mm), can be sexed correctly