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Southwestern willow flycatcher

SWFL1The willow flycatcher (Empidonax traillii) is a widespread species that breeds across much of the conterminous United States. It is a neotropical migrant songbird that breeds in the southwestern United States and parts of Mexico, and winters primarily in parts of Mexico and Central America. This species is considered to be a riparian obligate, because it requires dense riparian vegetation within which to nest and the presence of surface water, or soil that is moist enough to support this dense vegetation. This riparian vegetation can be either native broadleaf plant species (i.e., willows, buttonbush, cottonwood, ash) or nonnative species such as tamarisk. Breeding habitat generally consists of a brushy and dense understory (≥ 3m tall) with significant amounts of live foliage. SWFL will breed in dense understory that includes a taller canopy of larger trees (such as larger cottonwood and willows), but this is not a requirement as long as a dense and shrubby understory is present. The southwestern willow flycatcher (Empidonax traillii extimus, SWFL) is one of four subspecies of the willow flycatcher. The US Fish and Wildlife Service (USFWS) listed SWFL as an endangered species in 1995, primarily due to widespread loss and degradation of riparian habitats in the American Southwest.

To date, southwestern willow flycatchers have not been observed on any Pima County preserves. However, Pima County has committed itself to monitoring for the presence of this species using the USFWS-approved call playback survey protocol on the Cienega Creek Natural Preserve every three years. Surveys at the Bingham Cienega Natural Preserve were discontinued after staff determined that suitable SWFL breeding habitat no longer existed due to excessive drying of the once wet cienega.

Photo by Dave Menke - USFWS.