Stacey Cole's Nature Talks: Is avian conjunctivitis why sparrows, goldfinches are dying?
STACEY COLE |
November 01. 2013 10:03PM
Not long ago I received a letter from a North Woodstock reader who wrote in part: "I have had more than 50 sparrows and goldfinches die so far this summer. Some say it is a virus, their eyes get sticky so they can't see the food. Thought first it was a neighbor's cat. No. Thought it might be my bird seed or feeders. Changed all my bird seed and cleaned the feeders with bleach, rinsed well. Received my Birds and Blooms. They had an article of doves coming in with virus. We have plenty of doves. Chickadees and others are doing fine. Just sparrows and goldfinches are dying."
Although the symptoms our reader described were those of a bird infected with avian conjunctivitis, I had not heard of doves contracting the virus.
Avian conjunctivitis, is a bacterial infection, that, in some areas, has desiccated flocks of house finches. Other birds including purple finches, evening grosbeaks and pine grosbeaks, all members of the Fringilidae family, also have been susceptible to this virus. I believe our first column in Nature Talks about the eastern population of house finches dying by conjunctivitis appeared in 1996. It told about house finches and it has been and continues to be the one species of birds most severely affected. Occasionally we noted a few cases of the disease confirmed in American goldfinches. Also, for a number of years, the Cornell Laboratory of Ornithology, located at Sapsucker Woods in Ithaca, N.Y., has been closely tracking the spread of the bacterial infection causing conjunctivitis-ike symptoms in affected house finches. This project, referred to as "The House Finch Disease Survey," was unfortunately dropped a few years ago for lack of money to fund it.
The complaint, commonly referred to as the "house finch disease (avian conjunctivitis)," was first known to affect house finches during the winter of 1993-'94 in the states of Virginia and Maryland. Mycoplasmal conjunctivitis, as the disease is currently known, is caused by a parasite bacterium previously known to infect only poultry. Its spread was rapid through eastern house finch populations so that by November 1994 the epidemic had widened, mainly north, and covered a triangular region between Virginia, southern Ontario and southern New Hampshire. By November 1995 the disease had spread into the south, reaching Georgia and to Illinois in the Midwest. It has continued northerly as far as Quebec, Canada. The next year it had moved into Missouri, Iowa, and Minnesota. The disease has continued its spread.
In the Autumn, 2004, issue of "Birdscope," a publication of the Cornell Laboratory of Ornithology, it was reported: "Ten years after house finch eye disease was discovered in the East an epidemic breaks out on the opposite side of the continent. The data shows that the disease began spreading epidemically in the Northwest (British Columbia, Alberta, Washington, Idaho, Montana, Oregon and Wyoming) in early 2004. In February through April, 2004, disease prevalence had reached 15 percent in the Northwest, half again the highest level previously observed."
Although epidemic outbreaks appear to have pretty much skipped the middle of our country since it swept through house finch populations here in the eastern United States, it is not expected to disappear any time soon. It is always possible that the disease may make inroads into other members of the Fringilidae family.
When a sick or dead bird is found within a bird feeding area it should be a strong reminder that keeping such areas uncontaminated is of vital importance. A thorough cleaning can be quite a chore, especially during the heavy winter feeding time.
Bird feeders should be cleaned in a solution of nine parts of tepid water and one part bleach, soaked for two or three minutes in the solution, rinsed and thoroughly dried.
While feeders are down, the feeding area beneath should be cleaned as best as can be done. If possible, allow any wet areas to thoroughly dry.One should watch for signs of disease by observing the actions of the birds that visit feeders. Diseased birds are usually lethargic and sit quietly with their feathers all puffed up. It does not take long for the bacteria to spread through its body and a bird will die quickly.
In the case of a serious disease outbreak, feeders should be taken down immediately and kept down for a period of 2 to 3 weeks. If a second outbreak occurs shortly after the feeders are replaced they should once again be taken down and remain so for the rest of the season.
If regular or electrically heated bird baths, or any type of watering device is used in winter, they also should be washed and disinfected. A good sanitation program is a must for anyone who feeds birds.
Stacey Cole's address is 529 W. Swanzey Road, Swanzey, 03446.