New findings suggest increasingly dry conditions have halved Mojave’s bird populations over the last century. It’s a warning for the desert — and the world
“It wasn’t what we expected,” says Kelly Iknayan, a PhD student at the University of California, Berkeley, and the lead author of the study. According to Iknayan, similar avian surveys that were conducted in the Sierra Nevada and Central Valley yielded “a little bit more balance” — only a slight increase in the number of species in the Sierras, and a slight decrease in the Central Valley. In comparison, the changes in the Mojave were dramatic. “When we see a decline across a community like this, it also could potentially indicate that other things are out of balance.”
What’s out of balance is rainfall. Climate change has altered precipitation patterns in the desert, leading to the survey sites receiving 20 percent less precipitation than when they were first studied. Precipitation impacts the amount of surface water available and the health of the plants birds use for sustenance and hydration. The researchers determined that this decline in rain and snow was the major cause for the shriveling bird populations, not rising temperatures (which have not yet increased to the point of dehydrating birds more rapidly) or increased wildfires caused by flammable invasive species.
Desert birds seek refuge in areas with higher elevation, more surface water, and higher levels of precipitation. But over time as precipitation continues to decline, these refuges are also drying up. Birds are more likely to suffer from lethal dehydration before they can escape to the refuges or move out of the desert Southwest all together.