Comments / Research Needs:
Eye colour (blue, grey, brown or some combination), brightness of red feathers of the orbital ring, and bill length and colour may assist in determining age and sex.. but molecular DNA analysis remains the most reliable technique for determining sex (Kennedy 2009; Kennedy and Marra 2010).
Kennedy, C.M. 2009. Matrix effects on individual and community-level responses of birds to forest fragmentation in Jamaica. In: Biology, Ecology, Evolution and Systematics. University of Maryland, College Park. Pg. 198.
Kennedy, C.M. and P.P. Marra. 2010. Matrix mediates avian movements in tropical forested landscapes: Inference from experimental translocations. Biological Conservation 143:2136-2145.
Pyle, P., A. McAndrews, P. Velez, R.L Wilkerson, R.B. Siegel and D.F. DeSante. 2004. Molt patterns and age and sex determination of selected southeastern Cuban landbirds. J. Field Ornithol. 75:136-145.