(White-eyed Vireo photo by Lloyd Spitalnik.)
The reason for the bird's presence in the sycamore tree was very evident. The tree is just full of small green caterpillars right now. They're the larvae of a small moth. Vireos love caterpillars and the bird I watched today was stuffing his face with them! He moved up and down the limbs and twigs, turning over leaves as he went, searching for those juicy caterpillars and he was finding plenty of them.
These vireos do nest in our area and I'm hoping to have a pair in my yard this summer.They build a well-constructed nest that is a deep, hanging cup made of such things as twigs, roots, shreds of bark, grass stems, leaves, plant down, lichen, moss, and sometimes even fragments of wasp nests. They bind the nest together with spider webs and line it with fine grass and fibers. Usually the nest is built relatively low to the ground in a shrub.
The female generally lays four eggs in the nest and both parents take turns incubating for about 13-15 days. Unfortunately, these birds are often parasitized by Brown-headed Cowbirds that lay their own eggs in the vireos' nest. The White-eyed Vireo may have as many as two broods during our long, long summers.
They are lovely birds and great fun to watch when you can manage to find them among the dense leaves. Today, I got lucky.