A morphometric model to predict the sex of virginia rails (Rallus limicola)

Virginia rails (Rallus limicola) are secretive marsh birds found in freshwater wetlands across much of North American. There is currently no known way to differentiate between the sexes in the field. We suggest the use of morphometric discriminant analysis as an effective method to separate males and females. We compared the length of the culmen, tarsus, wing chord, and middle toe of live birds captured at Ottawa National Wildlife Refuge (Ottawa Co., OH) during the springs of 2002-2011 and museum specimens measured the summer of 2011. We genetically determined the sex of a subset of samples using an intronic region of the chromo-helicase-DNA-binding gene on the Z and W chromosomes. For live birds, 81% of males and 70% of females were classified correctly; and for museum specimens, 71% of males and 80% of females were classified correctly. This technique provides an accurate and simple method of determining Virginia rail sex that can contribute to efforts to better understand population demographics.