Identifying the sex of a bird is important to ensure successful breeding strategies and effective conservation programs, especially for endangered species.2 Sex can be identified from the intron size of the CHD1 gene located in avian sex chromosomes Z and W.2-4 Most birds are vulnerable to stress during sampling, however, so obtaining a sufficient amount of genomic DNA while causing the least amount of harm is a critical issue.
The Nicobar pigeon (Caloenas nicobarica) is a CITES I, highly threatened species distributed in southeast Asia. The major threat to its persistence is stress, especially from disturbance during breeding.
With cut feathers as samples, we successfully determined the gender of Nicobar pigeons. We found that the rachis segment of a cut feather contained sufficient amounts of DNA for determining sex. This indicates that cutting instead of plucking the feather is feasible; a cut feather including the rachis can be a superior method, because it decreases stress on the examined birds and is accomplished easily. Further, feather tips are also a favorable DNA source for identification of avian leukosis and Marek’s disease pathogens.1 This sampling method thus simultaneously facilitates screening for these important avian tumorigenic diseases.
We thank the technicians at the vet department of the Taipei Zoo for their kind help with sampling.
1. Davidson, I., and R. Borenshtain. 2002. The feather tips of commercial chickens are a favorable source of DNA for the amplification of Marek’s disease virus and avian leucosis virus, subgroup. J. Avian Pathol. 31:237–240.
2. Fridolfsson, A.K., and H. Ellegren. 1999. A simple and universal method for molecular sexing of non-ratite birds. J. Avian Biol. 30:116–121.
3. Griffiths, R., M.C. Double, K. Orr, and R.J.G. Dawson. 1998. A DNA test to sex most birds. Mol. Ecol. 7:1071–1075.
4. Kahn, N.W., S.J. Judith, and T.W. Quinn. 1998. Chromosome-specific intron size differences in the avian CHD gene provide a simple and efficient method for sex identification in birds. Auk 115:1074–1078.