RIVERSIDE, Calif. — The Salton Sea, California’s largest lake, has been drying up for decades thanks to a combination of drought, reduced agricultural inflow and the diversion of Colorado River water to other regions like San Diego.

The lake has been a crucial part of the Pacific Flyway since its accidental formation in 1905, providing migratory bird species with hundreds of square miles of wetland habitat.

As the Salton Sea has shrunk, its salinity has increased, leading to the death of nearly all fish and invertebrates like pile worms that once lived in the lake. Without those reliable food sources, the number of migratory birds visiting the Salton Sea has drastically declined. 

Ornithologist Robert McKernan of the Oasis Bird Observatory has been documenting bird populations in the region for decades and he says the decrease has become especially pronounced in the last few years.

“[In] 2016, 2017 is when you could start noticing decline, and in 2021, 2022 and now 2023, it’s fairly evident,” McKernan said. 

The number of Eared Grebes, that once flocked to the lake in the millions, has been reduced to just several thousand, according to the Audubon Society. The numbers of visiting Brown and White American Pelicans have also seen marked declines. 

According to the research nonprofit Pacific Institute, the lake’s water levels have dropped by over 10 feet in the last two decades. In addition to affecting bird species, the lake’s decline has led to an array of negative impacts on local communities ranging from economic turmoil to an increase in respiratory illness. 

Though this year saw record rainfall, experts like McKernan say far more water is needed to raise the lake’s levels and lower its salinity if wildlife is to once again thrive in the region. 

There are already some habitat conservation projects in the area like the California Salton Sea Management Program, but McKernan says those will only do so much. 

“Those will be postage stamps compared to the Salton Sea, the size and significance of the Salton Sea and what it provided to bird species,” McKernan said.