ABSTRACT 
Steroid hormone components from the plasma of several avian species, 
including bald eagles (Haliaeetus leucocephalus), barn owls (Tyto alba), 
and black-crowned night herons (Nycticorax nycticorax), were separated by 
centrifugal chromatography on silica gel columms. Identification of sex 
was primarily by staining of steroid hormone bands with iodine, charring 
with sulfuric acid, and observing fluorescence under ultraviolet light. 
Techniques were standardized using plasma from known-sex Japanese 
quail (Coturnix coturnix japonica), mallard ducks (Anas platyrhynchos), 
and American kestrels (Falco Ssparverius). Before attempting to sex these 
species, or the eagles, owls, and herons that lack external sexual dimor- 
phism, a "blind trial" was conducted on a known-sex pair of a particular 
species. All of these methodological tests were uniformly successful. 
Quantification and positive identification of each of the steroid hormone 
components have not been completed, but the described techniques are 
sufficient to distinguish sex. 
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