Biometrics, sexual dimorphism and gender determination of Griffon Vultures Gyps fulvus from Crete

Abstract

In the present study we describe the morphometries of 97 live Eurasian Griffon Vultures Gyps fulvus collected on the island of Crete (Greece) and a sex determination model on the basis of various field techniques and multivariate data analysis. We determined the sex of 49 individuals with sex-specific DNA markers and polymerase chain reaction using DNA extracted from blood samples. Adult birds were generally larger than young ones with the wing chord being the only significantly different character. Male Griffons were smaller than females for most body characters and significantly larger (c. 3-5%) for head length, head width, bill length and bill length including the cere. A stepwise discriminant function analysis showed a high predictive power in gender determination by classifying 94.1% of the individuals of known sex that was not reduced by a jackknife cross-validation technique.