A population boom in the Bay Area is causing quite a flap as thousands of California Gulls swarm piers, inundate wetlands, harass airplanes, swoop down on students at schools and generally make a mess of things.

In 1980, there were only 24 of the birds in the area and they were considered a “species of special concern” in California, according to MSN News. Now larus californicus are said to number more than 53,000 and continue to breed at a quickening pace. It’s estimated that there are 41% more of them now than there were two years ago and they have a life expectancy of 25 years.

Cheryl Strong, a biologist with the Don Edwards San Francisco Bay National Wildlife Refuge, told the San Jose Mercury News that the gull population could double in the next few years, but said, “I don’t want to think about that.”

There are reportedly 10 colonies of the birds scattered all over the region, from Richmond to San Jose. They are endangering a $300 million wetlands restoration of the former Cargill industrial salt ponds and wreaking havoc during San Francisco Giants baseball games at AT&T Park.

They are gobbling up endangered species, in addition to their usual diet of just about anything that moves, including fish, bugs and their own young. If the gulls run out of living things, they are also quite fond of garbage, which they find in plentiful supply at the landfills they blanket.  

According to the Mercury News, no one is quite sure why they are proliferating so quickly. But some are pointing to an explanation increasingly cited as an explanation for the inexplicable: global warming.

A 2006 research report (pdf) that studied the gulls at their historical breeding ground found that the two factors affecting their population growth the most were food and heat. When the temperatures rise, the gulls lay more eggs.

–Ken Broder

To Learn More:

Bay Area Sea Gull Population Explodes, Bringing Flocks of Problems (by Paul Rogers, San Jose Mercury News)

California Has a Problem: Gulls Gone Wild (by Heather Smith, MSN News)

California Gull (National Geographic)

Annual Variation in Numbers of Breeding California Gulls at Mono Lake, California (by Peter H. Wrege, W. David Shuford, David W. Winkler and Robert Jellison, Cooper Ornithological Society 2006) (pdf)