Birds and Water in the Western U.S.

American Avocets in the Salton Sea. Photo: David Tipling/NPL/Minden Pictures

Water is the most precious resource in the West—for people, birds, and other wildlife. Riparian habitats like the forests and wetlands that line the Colorado River support some of the most abundant and diverse bird communities in the arid West, serving as home to some 400 species. The Colorado River also provides drinking water for more than 36 million people, irrigates 5.5 million acres of farms and ranches, and supports 16 million jobs throughout seven states, with a combined annual economic impact of $1.4 trillion.

 

But dams, diversions, drought, and water demand along the Colorado River have devastated cottonwood-willow forests and other native riparian habitat that support more than 40 percent of bird species in America’s Southwest. Saline lakes—the landlocked saltwater lakes fringed with wetlands that dot the Intermountain West—are beacons for millions of birds crossing an otherwise arid landscape. But as water recedes and exposes toxic dust, not only is habitat lost, but surrounding communities are at higher risk for asthma and other health issues.

 

In short, precipitous declines in Western water quantity and quality are exacting a high toll on the health, prosperity, and quality of life for rural and urban communities, and putting birds and wildlife at jeopardy.

 

Water and Birds in the Arid West: Habitats in Decline represents the first comprehensive assessment of the complex and vital relationships that exist among birds, water, and climate change in the region. Our research focused on two of the most imperiled and irreplaceable Western ecosystems: 1) the Colorado River Basin; and 2) the West’s network of saline lakes—including the Great Salt Lake and Salton Sea as well as other smaller but vitally important lakes. To read the full report, click here. Have questions? Read the FAQ. Want to get up-to-date news on water issues in West? Join the Western Rivers Action Network

 

Saline Lakes of the Intermountain West

We focused our analysis on the nine western saline lakes with the greatest importance for birds. More than half of these have shrunk by 50 to 95 percent over the past century. However, despite widespread awareness of the importance of water—and concern about adequate Western water supply—much of the available research on saline lakes and birds was focused on individual lakes. By bringing this work together, we were able to better understand how birds “use” the widely dispersed lakes and wetlands as an interconnected network of habitats. No other linked ecosystems in the Intermountain West can meet these birds’ unique requirements—and because shorebirds and waterbirds congregate in large numbers at major lakes, they are particularly vulnerable to habitat loss.

 

Key findings:

  • Collectively, saline lakes in the West support global populations of birds, including over 99 percent of the North American population of Eared Grebes, up to 90 percent of Wilson’s Phalaropes, and over 50 percent of American Avocets.
  • Saline lakes are critically important to migratory shorebird species, whose populations have declined nearly 70 percent since 1973.
  • Water levels in saline lakes have declined dramatically in the last 100+ years due to draining, diversions of inflows, and lake and groundwater extraction.
  • Lower water levels have increased lake salinity, altering food webs and reducing invertebrate food sources for migrating and resident shorebirds and waterbirds.
  • Drier conditions under climate change will exacerbate the impacts of water diversion on saline lakes by decreasing freshwater inflows.

Birds That Depend on Saline Lakes

   

Water in the Colorado River Basin

Although riparian zones account for less than 5 percent of the southwestern landscape, they support over 40 percent of all bird species found in the region and over 50 percent of the breeding bird species. These include at least 400 unique species along the lower Colorado River. As dams, diversions, and flow regulation, along with drought and increased demand for water, eliminate native cottonwood-willow forests along the Colorado River, many bird species face diminished and degraded habitat and an uncertain future.

 

Key findings:

  • Native riparian trees and shrubs such as cottonwood-willow ecosystems that pro-vide productive habitat for birds and other wildlife are disappearing as a result of water development—including damming, flow regulation, surface water diversion, and groundwater pumping.
  • Hydrology changes have also spurred the spread of non-native plants, particularly saltcedar, throughout the Colorado River Basin—reducing biodiversity and the number and variety of birds in many riparian habitats.
  • Populations of the following breeding birds, once common along the Colorado River, have experienced significant regional declines: Bell’s Vireo, Yellow Warbler, Yellow-breasted Chat, and Summer Tanager.
  • Three species—Yuma Ridgway’s Rail, Western Yellow-billed Cuckoo, and Southwestern Willow Flycatcher—are now listed as federally threatened or endangered, and at risk of extinction if current trends continue.
  • Climate change is projected to exacerbate habitat declines across the basin, reducing water supply, raising temperatures and aridity, and disrupting phenology—the timing of seasonal natural phenomena such as spring floods, plant flowering, and insect hatching.

Birds That Depend on the Colorado River