A New Method to Sex Barn OwlsTyto alba

Nominate Barn Owls Tyto a. alba can be sexed based on flecking patterns of the underwing and underbody, but in the Dutch population consisting of the nominate subspecies and T. a. guttata, overlap in flecking exists between the sexes. In this paper we describe a new method to sex Barn Owls based on apical bar widths of the primaries. Data were obtained from 240 dead Barn Owls that were sexed by autopsy. The apical bars of the primaries 10 and 8...