The birds I see with the greatest frequency here in D.C. are American robins. I see them all year round too – they are permanent residents. Even though I see robins on a daily basis, I never have any idea if the robin I am looking at is a male or a female. They look exactly the same to my eye, though my understanding is that the females are slightly paler than the males.
Some birds are like that – the males and females look almost the same. But many birds are sexually dimorphic and there are differences between the sexes that are obvious.
We were absolutely thrilled when we saw a black-throated blue warbler perched on a tree branch on the edge of the cove. I was immediately able to see that the bird was male. Male and female black-throated blue warblers do not look alike.
The males have black throats, black faces, and are a bright-blue color on the tops of their heads and down their backs. Their tummies are white. The females are a dull greenish-brown color with yellowish-white bellies.
As far as I know I have never seen a female black-throated blue warbler, but I cannot say for sure. Since the females are less flashy than the males, it seems like I may have seen one and not realized it.
When I got home from our walk to Fletcher’s Cove, I looked black-throated blue warblers up in my birding field guide to refresh my memory regarding what the females look like. I learned that the males and females have one plumage thing in common: they each have a white patch on their wings. This white patch will help me identify a female if I am ever lucky enough to see one. I’ll keep my eyes peeled and let you know if I do!