Status and breeding ecology of the southwestern willow flycatcher in the Grand Canyon

Ernpidonax trailIll extirnus is one of several recognized subspecies of the Willow Flycatcher (Unitt 1987, Browning 1993), a neotropical migrant that breeds across much of North America. This southwestern race is a riparian obligate, nesting in dense patches of willow (Salix sp.), willow-cottonwood (Populus sp.), or other similarly structured habitats. In some areas of the Southwest, it nests in dense stands of tamarisk (Tamarix sp.). Willow Flycatchers were once widespread and locally common in the Southwest (Unitt 1987) but have declined to the point that E. t. extirnus was listed as an endangered subspecies in 1995 (USFWS 1995).