BREEDING ECOLOGY OF A WILLOW FLYCATCHER POPULATION IN GRAND CANYON, ARIZONA

Abstract

The Willow Flycatcher (Empidonax traillii) is a widely distributed summer resident insectivore breeding across most of the United States and southern Canada (A.O.U. 1983). The subspecies of Willow Flycatcher occurring in the arid southwestern United States and extreme northwestern Mexico, E. t. extimus Phillips (1948), has decreased substantially in numbers in the past few decades (Hunter et al. 1987, Unitt 1987).