For the Birds Radio Program: House Finch Eye Disease

Original Air Date: Aug. 21, 2000

Why are House Finches suddenly looking sick? (Out-of-date website and other information)

Duration: 4′20″


I’ve been getting a few phone calls and e-mails from listeners, mostly in Central Minnesota, regarding some House Finches that have nasty-looking deformities in and around their eyes. These birds are suffering from a frequently fatal disease called mycoplasmal conjunctivitis, which is contagious but less virulent than some disease organisms. Birds can survive with it, but usually become blind, and eventually starve or are taken by a predator. And birds apparently must be in close proximity to pass the bacterium back and forth.

This eye disease, a strain of a common poultry pathogen, was first described in 1994, when birders in Virginia and Maryland reported seeing House Finches with red, swollen, crusty eyes. Since that time, sightings of infected birds have spread. Confirmed cases have been reported to the eastern edge of the Great Plains, and there are unconfirmed reports of the disease even farther west. Conjunctivitis predominantly affects House Finches, but a few infected goldfinches, Purple Finches, and House Sparrows have also been found.

The most effective medicine is prevention, and if you discover infected House Finches in your yard, your two best courses of action seem contradictory: either increase the number of your feeders to keep birds from coming in close contact with one another (keeping feeders as clean as possible!) or close down your feeding station altogether for a week or two, allowing the finch flock to break up.

The Cornell Laboratory of Ornithology has been tracking the spread of the disease thanks to the volunteer efforts of thousands of backyard feeder watchers who send them feeder information in the mail or via the Internet. To learn more about the disease or participate in the House Finch Disease Survey, check out the Laboratory’s web page at , or connect to it via my web page at .

Valuable House Finch population information also comes from participants in the Laboratory of Ornithology’s Project Feeder Watch. There is a $15 cost for participating in this project, to cover postage and the materials the Lab sends, including an instructions booklet for counting birds, the Feeder Watcher’s Handbook, full of information on birds and bird feeding, data forms for sending in your data, a one-year subscription to Birdscope, the newsletter of the Lab of Ornithology, a full-color poster of common feeder birds, and a colorful bird-watching days calendar to help you keep track of your bird counts. The Lab also offers a Classroom Feeder Watch program with a complete set of classroom lessons, activities, and materials. To learn more about this project, check out the Lab’s web page at or call 1-800- 843-2473. This information is also available on my web page.

Two decades ago there were no House Finches in Wisconsin or Minnesota, but now they’re a welcome addition to our birdlife, filling out backyards with song and our hanging baskets with their nests. They’ve out-competed House Sparrows in the backyard feeding niche in many areas, but overall don’t seem to be causing much or any harm to native birds. It doesn’t take much to protect them and to help track the course of a disease decimating it in many places–Cornell makes their research projects fun and interesting, and like any volunteer effort to make the world better for one of God’s creatures, helping makes the world a better place for all of us.