Sex-typing bird species with little or no sexual dimorphism: an evaluation of molecular and morphological sexing

Abstract

Many avian species are either sexually monomorphic or display a small amount of sexual dimorphism. In such cases, sex determination based on morphology is difficult. Molecular sexing methods are available, but choosing the right method and protocol depends on the study species. Here, we compared a molecular sexing method and the reliability of standard morphological sex determination in eight bird species that display little or no sexual dimorphism, including the endangered Eurasian griffon vulture, Gyps fulvus. Two molecular sexing protocols that employ a different set of primers were used. In addition, feather and blood samples were compared as DNA sources. The P2/P8 primer pair was effective in Passeriformes, whereas the 2550F/2718R was not. The opposite was true for the two species representing Falconiformes and Pelecaniformes. Morphological sex determination was subject to error in species with little sexual dimorphism.