The Use of Flow Cytometry for Rapid Identification of Sex in Birds

Unambiguous identification of the sex of live birds is critical in numerous areas of avian research, including studies of alternative reproductive tactics, sexratio manipulation, and conservation biology (e.g. van Rhijn 1973, Snyder and Snyder 1989, Stamps 1990). However, identification of sex can be problematic for researchers dealing with young birds or sexually monomorphic species. Techniques currently available for identification of sex, primarily based on cytogenetics or biochemical genetics, are time-consuming, expensive, or require considerable amounts of tissue. The use of sex-specific DNA probes can overcome some of these shortcomings (Quinn et al. 1990), but this technique is time-consuming also, and probes may not be equally effective with DNA of species from divergent taxonomic groups. Other techniques such as laparotomy do not always work with nestlings or sexually immature birds, are potentially stressful, and may be inadvisable when dealing with threatened or endangered species.