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Southwestern Willow Flycatcher

 

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  • Willow Flycatcher perches on a branch. Credit: Dave Menke, USFWS.

    Willow Flycatcher perches on a branch. Credit: Dave Menke, USFWS.

  • Willow Flycatcher by Seabamirum, on Flickr.

    Willow Flycatcher by Seabamirum, on Flickr.

Southwestern willow flycatcher (Empidonax traillii extimus)

Species description: The southwestern willow flycatcher (Empidonax traillii extimus) is a subspecies of the willow flycatcher family. It has a grayish-green back and wings, whitish throat, light gray-olive breast, and pale yellowish belly. Two wingbars are visible and the eye ring is faint or absent. The upper beak is darker than the lower beak. The most distinguishing characteristic between the southwestern willow flycatcher and other willow flycatchers is their song, a sneezy "fitz-bew."

The southwestern willow flycatcher breeds in Arizona, New Mexico, and southern California, plus portions of southern Nevada and Utah, southwest Colorado. It winters in the rain forests of Mexico, Central America and northern South America. The flycatcher is a late spring breeder seen and heard in riparian forests by mid-May. It nests in trees and thickets in late May and early June, lays three to four eggs in one-day intervals with the young fledging in early July. There is usually only one brood raised per year, but multiple clutches are not uncommon.


Reasons for decline »

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Loss and modification of riparian habitat and nest parasitism by the brown-headed cowbird are key factors in the decline of flycatcher populations. River and stream impoundments, ground water pumping, and overuse of riparian areas have altered up to 90 percent of the flycatcher’s historical habitat. Livestock can also impact the riparian habitat of the flycatcher. These cool and shady streamside habitats are preferred by livestock that consume cottonwood and willow saplings when grass species are not available, depleting the density of vegetation. Since salt cedar is unpalatable to cattle, struggling willow and cottonwood saplings are eaten instead, thereby accelerating the change in habitat. Another threat is the brown-headed cowbird. This bird lays its eggs in the nests of other species. It removes one or more eggs from the nest and replaces them with its own. The eggs of the cowbird hatch sooner, the young grow faster, and are much larger and more demanding than those of the nesting bird. These young cowbirds then crowd out and starve the other hatchlings. Sometimes flycatchers will abandon their nests and start over, often too late in the season. Cowbird parasitism can greatly reduce the nesting success of the southwestern willow flycatcher. Healthy populations of birds can recover from losses due to nest parasitism, but cowbird parasitism on populations whose numbers are already reduced due to habitat loss can be the final straw.

Interestingly enough, riparian ecosystems may depend on the flycatcher as well. Studies have shown that predation on insects by birds actually results in the improved health of trees and forests. The southwestern willow flycatcher and other insectivorous birds in riparian woodlands consume huge numbers of insects per day, including mass quantities of mosquitoes. By controlling insect populations, flycatchers keep humans comfortable and contribute to the health of southwest riparian systems as well. To save the southwestern willow flycatcher, we must save these beautiful desert riparian ecosystems and the wondrous array of life within them.


Recent actions & links »

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Recent Actions: On Janurary 3, 2013, we published a final rule to designate revised critical habitat for the southwestern willow flycatcher under the Endangered Species Act.  In total, approximately 1,975 stream kilometers (1,227 stream miles) are being designated as critical habitat.  These areas are designated as stream segments, with the lateral extent including the riparian areas and streams that occur within the 100-year floodplain or flood-prone areas encompassing a total area of approximately 84,569 hectares (208,973 acres).  The critical habitat is located on a combination of Federal, State, tribal, and private lands in Arizona, California, Colorado, Nevada, New Mexico, and Utah.  The effect of this regulation is to conserve the flycatcher’s habitat under the Endangered Species Act.

Learn more about southwestern willow flycatchers and conservation efforts:

Arizona Field Office's website 
Service's Environmental Conservation Online System
Service’s Information, Planning, and Conservation (IPaC) System 

 

 

The mission of the U.S. Fish and Wildlife Service is working with Others to conserve, protect, and enhance fish, wildlife, plants and their habitats for the continuing benefit of the American People.
Last modified: July 05, 2018
All Images Credit to and Courtesy of the U.S. Fish and Wildlife Service Unless Specified Otherwise.
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