SALTON SEA, Calif. (KABC) -- Thousands of birds have been found dead at the Salton Sea.The California Department of Fish and Wildlife says ducks, gulls, and other birds were found dead at the south end of the lake between Jan. 8 and 17.Tests show signs of the avian cholera.Officials say outbreaks of avian cholera occur annually during the winter in California as a result of birds flocking close together during migration.Wildlife officials say they collected more than 1,200 carcasses of birds, including ruddy ducks, northern shovelers, blacked-necked stilts and gulls. Most of the carcasses were incinerated to prevent the spread of disease, although some were shipped as samples for laboratory testing.