A river bird...

Swooping from a willow thicket to catch insects over a desert stream, the southwestern willow flycatcher is an image of grace and beauty. But the destruction of streamside forests and introduction of exotic cowbirds have also made it one of North America’s most endangered songbirds.

Four or five recognized flycatcher subspecies live in North America. The desert southwest is home to the southwestern willow flycatcher, a sparrow-sized bird with a pale olive breast, contrasting white throat and pale yellow belly. The most reliable way to distinguish this subspecies from others is through its distinct "fitz-bew" song—a song that is sadly becoming harder and harder for even the most ardent birder to hear.

...in search of a river

This migratory songbird has suffered a century of steady decline. Strictly dependent on dense willows, cottonwoods and other species found along southwestern rivers and streams, the flycatcher has lost more than 90 percent of its habitat to a combination of livestock grazing, dams, water withdrawal, and urban and agricultural sprawl. As its habitat is fragmented, the flycatcher is also made more vulnerable to nest parasitism by brown-headed cowbirds and nest predation by other species.

Fewer than 1,000 breeding pairs of the southwestern willow flycatcher remain throughout its range. Nine years of nearly rangewide surveys (1993-2001) found a total of only 986 flycatcher territories spread across southern California, Arizona, New Mexico and southern Colorado, Utah and Nevada. Those breeding areas that support the largest number of flycatchers are in peril from fires, water projects, livestock grazing and replacement of native habitats by introduced plant species.

Surveys have also shown that the breeding sites are widely scattered and isolated, and most sites include fewer than five breeding pairs. Because most flycatcher populations are isolated, there is often little hope that populations will be rescued by immigration from other populations.

Treacherous waters

In recent years, reservoirs have become a particularly dangerous place for the southwestern willow flycatcher. Attracted to an abundance of water and dense vegetation, large flycatcher populations have congregated at reservoirs such as Lake Mead on the Colorado River and Lake Roosevelt on the Salt River. These habitats have proven to be death traps, where efforts to increase storage for the water-thirsty southwest have led to proposal after proposal to flood flycatcher habitat and destroy populations.

The Center protects the flycatcher—and its rivers

For over a decade, the Center for Biological Diversity has taken a leading role in protecting the flycatcher. In 1992, the Center authored a petition submitted by a coalition of environmental groups to place the flycatcher on the federal endangered species list. When the U.S. Fish and Wildlife Service refused to process the petition, the Center filed a series of lawsuits that forced the agency to list the flycatcher as an endangered species and protect more than 600 miles of rivers in California, Arizona and New Mexico as critical habitat.

The flycatcher was listed as endangered in February 1995. Two years later, the Center won an injunction protecting a critical flycatcher population at Lake Isabella, California until extensive mitigation lands are purchased. In 1998 the Center convinced the U.S. Forest Service to remove cattle from several hundred miles of rivers in Arizona and New Mexico, a move to restore some of the delicate riparian habitat the flycatcher needs to survive. The Center has also been actively involved in research and management, producing a pivotal report on the status of the species in 1998, participating in development of a federal recovery plan, and presenting papers at scientific conferences.

But the habitat destruction continues

The U.S. Fish and Wildlife Service has issued many take permits since the bird was listed. Given the critical status of the flycatcher and ongoing threats to its habitat, the Center will be involved in the fight to save the southwestern willow flycatcher and the riparian habitats it depends on for decades to come.

graphic Andrew Rodman ©2002
February 11, 2010
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