California's iconic Mono Lake, famous for its unique geological formations and prime location for birdwatching since millions of migratory birds visit it each year, has seen a huge decline in California gulls. Experts attribute the species' struggle to the changing temperatures and associated weather — specifically, record levels of rain and snowfall that occurred several winters ago. 

What happened?

According to the San Francisco Chronicle, tens of thousands of gulls normally arrive at the lake every summer to give birth. But last year, it became clear that the gull population was experiencing issues with reproduction. Just 324 birds hatched in 2024, marking the lowest number ever recorded. In comparison, 11,000 chicks hatched the year prior, according to the research group Point Blue Conservation Science.

"We're talking about a near-complete breeding failure," Ryan Burnett, Sierra Nevada director at Point Blue and a co-author of the report, told the outlet.

Part of the problem is a decades-long struggle with water management at the lake. The city of Los Angeles pumps water from creeks that connect to the Mono to supplement its water needs, though regulations are in place to reduce exports when the lake level falls below certain thresholds. Frequent droughts caused by the changing climate have also made it harder for gulls to survive. 

However, since just over 20,000 gulls arrived at the lake last year — a record low — the study authors knew something else must have caused such a rapid decline in their numbers. The Chronicle reported that the authors attribute the population collapse to "the historic amount of rain and snow that fell in the winter of 2022-23," which negatively impacted brine shrimp that gulls rely on for successful breeding.

Why is the decrease in California gulls concerning?

Since the lake is a crucial stopover for migratory birds, it's a well-known spot among bird enthusiasts. However, the troubles at Mono Lake may affect tourism and recreation activities, especially since California gulls are one of the most popular species for birdwatching. 

Aside from the human impacts, the decline in gulls will also disrupt the delicate saline ecosystem. As opportunistic omnivores, gulls help regulate the population of insects, fish, and rodents, and contribute to the decomposition of matter with their scavenging behaviors. Because of this, they benefit the ecosystem by recycling nutrients and providing insights into the health of Mono Lake by indicating changes in the availability of prey.

While Point Blue has observed a "steady decline" in California gulls over the past four decades, it said the last several years have been the worst for the species, largely because of erratic weather patterns. 

"The good years aren't as good as they used to be, and the bad years are much worse," Burnett said. "We're going to have more extreme conditions. We're going to bounce back and forth between drought and then get these big boom years. Neither is good for the gulls."

What's being done to protect the birds?

While Point Blue said the gull's numbers have mostly increased after challenging years, and the birds have colonized new areas recently, the poor outcomes at Mono Lake are concerning. If the ecosystem no longer supports a healthy bird habitat, this could indicate a longer-term issue at the lake. 

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The Mono Lake Committee, a nonprofit dedicated to protecting the lake, has called for stricter water regulations to help California gulls rebound and limit the impacts of freshwater inflows on the saltwater in the event of floods. 

The Los Angeles Department of Water and Power gets just 3% of the city's total water from the basin, but that number can really add up during years when the lake is especially low. 

Ultimately, further conservation efforts and more investments in desalination plants to increase the state's water resilience will likely make the biggest difference in protecting Mono Lake. But we can all help by switching to energy-efficient appliances or using eco-friendly transportation to reduce pollution and mitigate the impacts of the warming planet.

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