We spotted a black-throated green warbler building a nest in one of our big hemlocks about a month ago. Lucky for us, it was in a spot where we could see it right outside our living room window and we’ve had the spotting scope on it for a while.
Today I was taking a look, and for the first time I saw two warblers there - one in the nest, the other perched on the edge.
It looked like the one on the edge was feeding the one sitting on the nest.
Is that typical behavior? If not, what was I seeing?
Yes, it’s typical. In the Black-throated Green, only the female incubates. The male will feed the female on the nest, and also bring food to the nestlings, but he does not incubate.
I figured you’d know.
Is this the case with all warblers, or only the Black-throated greens? And how do you find out this stuff? I have Sibley’s Bird Behavior, but it seems like every time I look something up in it it has everything BUT the behavior I’m looking for.
And I confess, I just went to the SD for this one, because even though I know I have that Sibley guide somewhere, it appears to have wandered off…
I checked Warblers of the Americas; I have a pretty extensive library of bird books. A cursory check of species accounts suggests that in most warblers both sexes incubate, but a few are like the Black-throated Green in that the female does all or most of the incubation.
While in many small songbirds both sexes incubate, it’s not that unusual that only the female does so. And it’s not unusual for males to feed females on the nest.