A Discriminant Function for Predicting Sex in the Balearic Shearwater

Abstract

We evaluate sexual adult size dimorphism and provide a sex-discriminating function for the Balearic Shearwater (Puffinus mauretanicus). Blood samples taken from adults were used to sex birds by the amplification of the CHD gene. Linear discriminant analysis was applied to eight morphometric characters to determine whether any single variable or combination of them could provide reliable sex determination. Females were significantly smaller than males for most tested variables. Analysis indicated that head plus bill length and minimum bill depth were the most accurate variables in a discriminant function model, predicting sex with about 90% accuracy.