Zoological Studies

Sex Identification of the Black-faced Spoonbill (Platalea minor)

Yeong-Hsiang Cheng, Tzong-Fu Kuo, Der-Nan Lee, and Ching-Feng Weng (2006) The Black-faced Spoonbill (BFS), Platalea minor, endemic to East Asia, is a well-known species listed as globally “critically endangered”. It is difficult to recognize the gender of a BFS by its appearance; this can make it extremely difficult to implement human-assisted breeding programs, as well as evolutionary and ecological studies. In this work, therefore, a molecular approach was used to determine the sex of the endangered monomorphic BFS, as opposed to a morphological or histological approach. In Dec. 2002, an outbreak of Clostridium botulinum toxin type C killed many birds overwintering in the Tseng-Wen estuary, southwestern Taiwan, and this provided the opportunity to obtain muscle samples for DNA extraction. The polymerase chain reaction (PCR) with a single set of primers was employed to amplify a fragment in both the chromobox-helicase-DNA-binding genes (CHD)-W and CHD-Z; after electrophoresis, the products showed a single band in males, with females having a 2nd distinctive band. The PCR products for the CHD-Z and -W genes were 658 and 464 bp, respectively. The nucleotide sequences of these bands were further confirmed after cloning and sequencing. The nucleotide sequences of the CHD-Z and -W genes were 83% homologous. When using morphological and histological examination results for comparison, 26 birds (14 males and 12 females; sex ratio, 1.16) were correctly sexed using our test. This study is the first time that the gender of the Black-faced Spoonbill has been identified using the PCR technique; there is great potential for applying this tool for further investigations into the ecology and reproductive behavior of this species.