We encourage FeederWatchers to look for signs of the disease in House Finches, American Goldfinches, and a few other finches coming to their feeders and to report whether they see it or not.
In 2008, the House Finch Disease Survey ended as a stand-alone project, but monitoring the disease continued through the data collection protocol in Project FeederWatch. These data have been invaluable for documenting the spread of the disease and have motivating research that seeks to understand the reasons for persistence of the disease as well as its longer-term impact on House Finch abundance. This survey collected data on the spread and prevalence of a bacterial disease that now affects House Finches from the Atlantic to Pacific coasts. Starting in 1994, because of the efforts of participants across North America, the Cornell Lab of Ornithology started the House Finch Disease Survey. In 2006, however, the disease was found west of the Rocky Mountains and has since spread to House Finch populations throughout the west. Initially, House Finch eye disease primarily affected the eastern House Finch population, which is largely separated from the western House Finch population by the Rocky Mountains. The released birds successfully bred and spread rapidly throughout eastern North America. They were released to the wild in the East after pet stores stopped illegal sales of “Hollywood Finches,” as they were commonly known to the pet bird trade. Until the 1940s, House Finches were found only in western North America. Mycoplasmal conjunctivitis, as the disease is sometimes called, spread rapidly across the Eastern Seaboard, leaving House Finches listless, mostly blind, and vulnerable to predators and bad weather. Lab tests revealed that the birds had Mycoplasma gallisepticum, a parasitic bacterium previously known to infect poultry. In the winter of 1994, Project FeederWatch participants in the Washington, D.C., area began reporting that House Finches at their feeders had swollen, red, crusty eyes.