HAYWARD, Calif., July 21 (UPI) -- An exploding population of sea gulls is putting more pressure on endangered bird species in the San Francisco Bay area, experts say.
Tens of thousands of California gulls now live in 10 colonies on bay levees off San Jose, Palo Alto, Union City, Fremont, Richmond, Alcatraz Island and Hayward, leaving people to wonder what steps might be taken to get them under control, the San Jose Mercury News reported Saturday. Park workers and volunteers have taken to shooing them away by blasting horns, clapping and blowing whistles. Sometimes guns are used to thin out the flocks, the newspaper said.
The gulls try to eat least terns, which are small endangered birds that lay eggs at Hayward Regional Shorelin Park.
Scientists are mystified by the increase in the gulls' population from 24 birds in 1980 to the current number of 53,000, the Mercury News reported.
Nobody knows how to stop the population boom, which causes problems such as birds colliding with airplanes, swarming landfills, divebombing neighborhoods and schools, and eating shorebirds that governmental agencies have worked for years to bring back from the brink of extinction, the newspaper reported.
The voracious birds are a serious threat to the West Coast's largest wetlands restoration effort: the restoration of 15,100 acres of former South Bay Cargill industrial salt ponds back to their original tidal marshes. A main goal of that effort, which has cost taxpayers more than $300 million, is to increase the populations of endangered species, scientists said.