A California gull soars above Mono Lake in Lee Vining, California, on July 18, 2011. Decades of state water policy have contributed to the breeding failure of these birds, which saw just 324 chicks spring from 20,000 adult gulls. (Paul Chinn/The San Francisco Chronicle via Getty Images)
California gulls that nest at the eastern Sierra’s Mono Lake suffered a catastrophic breeding failure last year, according to the latest installment in a four-decade-long series of reports tracking the birds’ health.
“It was the worst reproductive year on the books for these birds at Mono Lake,” said Bartshe Miller, Eastern Sierra policy director for the Mono Lake Committee, a group that’s worked for decades to restore an ecosystem devastated by water diversions to Los Angeles.
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The report attributed the low survival rate to the scarcity of the brine shrimp essential to the breeding gulls’ diet. That scarcity, in turn, is the product of an unusual stratification of lake waters due to its artificially low levels.
“When gulls are nesting, they really depend on the abundant shrimp,” Miller said. “They basically gobble that up, and then they take it back to the nest and they regurgitate it for the chicks.”
Nesting California gulls circle overhead during a nest survey conducted by the San Francisco Bay Bird Observatory near the Dumbarton Bridge in Fremont on May 12, 2025. (Beth LaBerge/KQED)
The gulls’ reproductive crash is prompting calls for state water regulators to reconsider measures ordered more than three decades ago to restore Mono Lake’s degraded ecosystems.
In 1994, the state Water Resources Control Board issued a landmark decision that was meant to halt a half-century of excessive water diversions from the eastern Sierra’s Mono Lake and begin the long process of environmental recovery.
Crucially, the order aimed to create the conditions that would allow the lake’s water level to rise by about 17 feet — from 6,375 to 6,392 above sea level — to a point biologists testified would benefit key species.
Recurring droughts and continuing diversions from the lake by the Los Angeles Department of Water and Power have combined to keep Mono well below the target level. Its current surface elevation is 6,383 feet.
Numbers of both California gulls and the brine shrimp declined since the early 1940s, when LADWP began siphoning water from streams feeding the salty lake.
By the late 1970s, the declining water levels had exposed a land bridge that allowed coyotes to reach the gulls’ nesting ground on Mono Lake’s islands. The lake’s dramatically increasing salinity levels harmed the reproduction of brine shrimp.
The water board’s order, known as Decision 1631, included a provision to hold further hearings if the lake’s 6,392-foot target level was not achieved by 2014. That date came and went, and despite calls from the Mono Lake Committee and other environmental groups, the water board has yet to call a hearing.
In the meantime, LADWP continues to divert the maximum volume of water allowed under D-1631. Miller said a new water board hearing could focus on reducing LA’s diversions to permit the lake to rise more quickly to its target elevation.
A Water Resources Control Board spokesperson said in an email that while no hearing has been scheduled, the agency “continues to engage with key parties to evaluate timing for future actions and other Mono Lake-related activities.”
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