A method for sexing the chicks of Antarctic shags

CASAUX R.; RAMÓN A.; BARONI A.

ANTARCTIC SCIENCE

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2008 vol. 20 p. 147 - 148

0954-1020

Abstract: A total of 311 chick Antarctic shags Phalacrocorax bransfieldensis of 45-55 days old was sexed from the 1995-96 to the 2003-04 breeding seasons at Harmony Point, South Shetland Islands, Antarctica, by the use of a discriminant function estimated for adult individuals. Among the individuals sexed, 11.9% were recaptured when returned to the colony in subsequent seasons. The sex of these individuals was confirmed by vocalizations and behaviour. The overall effectiveness of the method was 91.9%; the wrong classifications were related to the effectiveness of the discriminant function instead of the validity of the method. The results presented here indicates that the use of discriminant functions estimated to sex adult specimens is an appropriate method to sex in the field chick Antarctic Shags older than 50 days. It is proposed that the methodology presented here could be also applicable in other dimorphic bird species.