An approach to sexing young Great Bustards Otis tarda using discriminant analysis and molecular techniques

Adult Great Bastards Otis tarda are sexually dimorphic, males weighing more than twice as much as females. However, there is no practical way to disti nguish sex in chicks by their morphology. In this paper we describe a discr iminant function, Tail Length/Weight, which correctly sexed 98.2% of 165 Gr eat Bustard chicks at two study areas in Spain, the Wildlife Reserve of Lag unas de Villafafila and the province of Madrid. The value for Tail Length/W eight separating the sexes was 0.099: Tail Lerlgth/Weight for males < 0.099 < Tail Length/Weight for females. We also show, that the recently describe d PCR-based sex determination technique using genomic DNA is valid for the Great Bustard. Both approaches should be useful fbr sexing young Great Bust ards in captive breeding programmes and studies on wild populations.