Seen carrying a caterpillar (?), so assumption is carrying food for young.
Birds I found flying about and perching on various trees. They were yellow on the face and breast, and brown on the back and wings. The birds were chasing each other around, making high-pitched, almost hissing calls.
14 Jun 2010.
Baldpate Mountain, Mercer Co, NJ.
This female, along with her even brighter male partner, were ferrying caterpillars relentlessly to a nest that I never could find. I'm hoping the inhabitant of the nest was not a cowbird, which is much larger than its foster parents and has a relatively huge appetite.
The Blue-winged Warbler (Vermivora cyanoptera) is a fairly common New World warbler, 11.5 cm (4.5 in) long and weighing 8.5 g (0.30 oz). It breeds in eastern North America in southern Ontario and the eastern USA. Its range is extending northwards, where it is replacing the very closely related Golden-winged Warbler, Vermivora chrysoptera.