Sexing of Juv. (1W) Black-faced Bunting Emberiza spodocephala personata

Abstract

I recorded crown color, wing length and primary molt of adult and juvenile Black-faced Bunting Emberiza spodocephala personata in Lake Furen (45°15'N, 145°23'E) and Fukushimagata Lagoon (37°54'N, 131°15'E), Japan, from late September to early November during 1987-1989. I took records of 99 adults and 544 juveniles. Crown color of the Black-faced Bunting can be used as a reliable sexing character for adults. Male is larger than female in wing length and the primary molt is completed in adult birds. In the juveniles, there are two groups in crown color, the greenish group has longer wing length than the brownish group. Post juvenile molt is either complete, partial, or 'no molt'. Regardless of crown color, the longest primary feather is longer in molted birds than in no molted. The male juveniles have greenish crown and longer wing length, than the female which is brownish on the crown. Thus, the wing length, crown color and primary molt can be used as a set of characters in sexing of juvenile Black-faced Buntings Emberiza spodocephala personata.