This article is submitted with permission from Allison Wells CORNELL LABORATORY of ORNITHOLOGY 159 SAPSUCKER ROAD, ITHACA, N.Y. 14580- 1999- (607)- 254-2473
BIRD WATCHERS HELP CORNELL SCIENTISTS MONITOR THE SPREAD OF AN AVIAN DISEASE AT FEEDERS
August, 2000, Ithaca, New York. With help from participants in Project Feeder Watch, a nationwide network of bird feeding enthusiasts, researchers at CORNELL LABORATORY of ORNITHOLOGY have been able to demonstrate for the first time that a naturally occurring disease can regulate the size of wildlife population. The findings from a study of mycoplasmal conjunctivitis in House Finches (Carpodacus mexicanus) and published recently in the Proceedings of National Academy of Sciences, could give scientists insight into the dynamics of other host/disease systems as well, including currently affecting fish in the Chesapeake Bay,possibly even AIDS.
The study found that high density populations of House Finches that became infected with mycoplasmal conjunctivitis experienced a dramatic drop in numbers within two or three years after the epidemic began and that they stabilized at about 40% of their previous abundance. At the same time, emerging House Finch colonies in which the disease was present increased approximately to those levels. Thus, byinflicting mass mortality in established populations but allowing continued growth where the species still colonized, conjunctivitis was still a factor regarding population size. This finding could shed light on research regarding the impact of AIDS and other diseases.
Since 1987, participants in Project Feeder Watch have been collecting information about their winter feeder birds and sending it to LABORATORY of ORNITHOLOGY. During the winter of 1993- 1994 Feeder watchers in Washington, D.C. area were the first to observe and report House Finches with swollen, crusty eyes. In response, lab scientists developed a protocol called The House Finch Disease Survey to help Feeder Watchers collect information about the new disease as it spread far and wide from its Mid Atlantic Coast origin. "We seized the unprecedented opportunity to monitor a wildlife disease from its onset to its epidemic stages and beyond," says Project Feeder watch leader, Laura Kammermeier. "What's more, this novel ability is solely dependent on volunteered observations of bird watchers all across the country. We could not have made this discovery without their help"
Mycoplasmal conjunctivitis is caused by a previously unknown strain of mycoplasmal gallisepticum, a bacterium that typically leads to respiratory infections in domestic poultry. This new strain, that also affects American Goldfinches (Carduelis tristis) and a few other wild bird species, causes the eye of the infected bird to become swollen and crusty. This may lead to blindness and death from exposure, predation or starvation as the birds become vulnerable and unable to forage for food.
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