Need some help with this one. It was very tiny and I could recognize the sound if I heard it. Was one long very high pitched Trrrillllllll.
Singing right in front of me!
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.