Swallow Gender Distinction

Nature Reports
By J. Millen

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Dennis Forsyth writes:

Last year the Swallows that nested here were very nearly indistinguishable in plumage and it took me a week before I was comfortable differentiating between the male and female.  This year there is no problem.  The first image below is the male. Note the white above the eye which is useful in distinguishing him from his cousin the Tree Swallow, another cavity nester.  He is strongly coloured all over while his mate in the lower photo is what Sibley calls a drab female.  Still a little white over the eye, but much less colour on the head and neck.  I think that around my place at least most females tend to be much brighter than this one.  Dennis

Violet-green Swallow, Tachycineta thalassina – Male
Violet-green Swallow, Tachycineta thalassina – Female