Mojave Desert Bird Species Have Declined By Almost Half

The Mojave Desert has gotten hotter and drier over the past 100 years, and this change has been especially hard on birds.

A new study from the University of California-Berkeley shows that bird species have fallen by 43 percent. That means once common birds are no longer common, and rare birds are now even rarer.

Steve Beissinger is a professor of conservation biology at UC Berkeley. He led the study, which was spurred by the centennial of biologist Joseph Grinnell's survey of California and Nevada wildlife.

“We thought as a great project for the centennial of the museum that we would go back and start to revisit these sites and see how changes in climate and land use have shaped where species are found today,” Beissinger said.

After three years of retracing Grinnell's steps through the western United States, Beissinger said researchers were surprised by what they found.

“We were going back to these sites and we’re re-surveying them and pretty soon we find that the desert is kind of half empty of birds,” he said.

Beissinger said 135 bird species were in decline, only one was increasing and four were introduced after Grinnell's original survey.

He said common birds like the northern mockingbird, prairie falcon, white-throated swift, western kingbird and even the morning dove — all birds that were common a century ago — were in decline.

Rarer birds have declined in greater proportion, Beissinger said. The common raven is the only species that has shown growth. Ravens can fly a great distance to get to water and are willing to eat a large variety of food.

“This is probably an early warning sign for changes that have taken place in the desert and it is pretty interesting that these changes … they seem to be related to long-term change or decline in precipitation,” he said.

He said climate change has winners and losers in most ecosystems, but life the Mojave Desert is already tough, which means a change in water supply makes it tougher.

“It is the Mojave that is really sticking out as a place that’s changed in ways that aren’t very suitable for life,” Beissinger said.

Beissinger says he's not sure if the decline will continue but the climate models he has seen shows what could be ahead.

“All the climate models continue to predict a future that is hotter and drier for the Southwest,” he said.

He said what is happening in the Mojave Desert bird population shows that our favorite places are being impacted by a changing climate in ways we may not be able to control.

“There is a sense of beauty and openness and awe of nature that I think is something we’re going to miss,” Beissinger said.

Steve Beissinger, professor of conservation biology, UC Berkeley