Publication

Water Requirements for Southwestern Willow Flycatcher Habitat and Nesting at the Pueblo of Isleta 2006-2007 Final Report

URL: https://webapps.usgs.gov/mrgescp/documents/Smith%20and%20Johnson_2008_Water%20Requirements%20for%20SWFL%20Habitat%20and%20Nesting%20at%20the%20Pueblo%20of%20Isleta.pdf

Date: 2008/02/22

Author(s): Smith J., Johnson K.

Publication: Natural Heritage New Mexico Publication Number 08-GTR-329, 45 p.

Abstract:

The southwestern willow flycatcher (SWFL, Empidonax traillii extimus) breeds in riparian habitats of the southwestern United States. In 1995, the southwestern subspecies of the willow flycatcher was listed by the U.S. Fish and Wildlife Service (USFWS) as federally endangered (USFWS 1995). A primary cause of the species’ decline is habitat loss due to water diversion, impoundment, and channelization (USFWS 2002).

Throughout the southwest, SWFLs nest in dense riparian vegetation near lentic water; e.g., slow-moving streams, river backwaters, oxbows, or marshy areas (Sogge and Marshall 2000). These riparian habitats are created by hydrological events such as periodic flooding, sediment deposition, inundation, and groundwater recharge. SWFLs often place their nests in trees or shrubs that are rooted in or hanging over standing water (Whitfield and Enos 1996, Sferra et al. 1997). Surface water may be present early in the breeding season, but drying may leave soils damp or even dry later in the season. If traditional nesting areas become consistently dry due to drought or reservoirs receding, flycatchers may use the site for a breeding season or two, but over longer periods suitable riparian vegetation cannot be maintained, and dry sites are ultimately abandoned (Sogge and Marshall 2000).