Tulare Lake

January 11, 2024

Question: Is it likely that Tulare Lake will continue to exist year after year, or could it drain off and disappear again?

Answer: When it’s full of water, Tulare Lake in Kings County is practically the size of Lake Tahoe. The major rivers which feed Tulare Lake are dammed and diverted for agricultural and municipal water uses so the lake only fills during exceptional rain years. Tulare Lake made a dramatic reappearance last year after a heavy rainy season, and the lake is likely to remain present in 2024 with rainfall predictions once again being above average.

CDFW is deeply involved in the monitoring of Tulare Lake because of the health implications for the state’s bird populations. As a main landing spot within the Pacific Flyway, millions of waterfowl, shorebirds and other bird species are expected to spend time there. It’s because the water is stagnant and too warm in summer months that avian botulism occurs.

The disease is caused by a toxin-producing bacteria that appears naturally in bodies of water like Tulare Lake. During bacterial growth, the botulinum toxin becomes concentrated in the bodies of invertebrates, such as fly larvae, which are then eaten by waterfowl and other birds, infecting them.

The last large avian botulism outbreak in Tulare Lake happened in 1983 when approximately 30,000 birds, mostly waterfowl, died. The numbers were far more encouraging last year, with fewer than 5,000 deaths. CDFW worked with the US Fish and Wildlife Service, UC Davis School of Veterinary Medicine’s, Oiled Wildlife Care Network and California Waterfowl to quickly collect dead birds to slow the spread of the bacteria and treated more than 1,200 birds releasing nearly 900 healthy birds back into the wild.