Sex Determination in Manchurian Crane Grus japonensis by Discriminant Analysis

Abstract

Application of discriminant analysis to sex determination in Manchurian Cranes Grus japonensis was discussed, using following four measurements from 8 males and 14 females; tail length (TL), wing length (WL), tarsus length (LL) and bill length (BL). Following discriminant function was obtained:
Z=0.16887TL+0.01329WL-0.21827LL+1.06610BL-15.35077
Sex of the birds is determined by sign of this discriminant score (Z), as males when Z>0 and as females when Z<0. The difference of average score between 8 males and 14 females was significantly large (df=20, t=9.144, p<0.001).
This method of sex identification in this rare bird using measurements in several parts of the body is thought to be useful at zoo or field because of its easiness and immediateness. However, collection of more data of body measurements and other items for measurement should be needed in order to obtain more accurate discriminant function.