In a recent post, Birding for Fun and Profit, I mentioned that volunteer birders across Canada and the U.S. are instrumental in assisting with research related to wild bird populations by submission of raw data observations of kinds and numbers of birds visiting yards and gardens. Aside from the pleasure of bird watching (and complementary teasing of friends and family which invariably accompanies the hobby), is the knowledge that bird watching advances true scientific efforts. Project FeederWatch has tracked the advancement of certain avian diseases and requests its citizen scientists to report instances in their data logs. This past week, for only the second time (and first time during my “official” Project FeederWatch period), I’ve observed a bird with symptoms of red, swollen, and crusty eyes which is caused by the bacterium, Mycoplasma gallisepticum.
This little guy was at my feeder this past week, unfortunately demonstrating a classic case of House Finch Eye disease, a kind of conjunctivitis caused by M. gallisepticum.
First observed in the mid-1990s by Cornell feeder-watching volunteers, this disease has spread throughout the House Finch, Haemorhous mexicanus, population of North America. The poultry respiratory disease made a species leap to wild House Finch populations and because the beginning of the epidemic can be traced to a specific point (Maryland) and time (February 1994), and because Cornell Lab of Ornithology’s Project Feederwatch was in full swing, volunteers reported sightings describing House Finches with symptoms of eye disease and scientists got to work.
Within a few years, reports of diseased House Finches were common throughout the U.S. With raw data provided by Cornell’s “army” of bird watchers and the creative impulse of a Cornell Lab scientist, Belgian-born ornithologist, André Dhondt, an interdisciplinary research team has studied the evolution of this new disease from its inception and analyzed its impact on a given population–in this case, the hapless House Finch. In the two decades since M. gallisepticum debuted in that small population of Maryland House Finches, the process of disease evolution–mutations coupled with population dynamics–is better understood, and scientists are now utilizing the gained knowledge towards a fuller understanding of disease spread in humans and development of immunities. For a fascinating read, check out this article: House Finch Eye Disease: Outbreak, Then Understanding.
As for my little diseased finch, I haven’t seen him in a couple of days. I have noted his presence on my data for the week. Last year, I always indicated “yes” and “zero” responses to the questions of if I looked for House Finch Disease and how many finches I saw. This week, it’s still a “yes” but now with a “one.” I’ve only seen one other House Finch with crusty eyes and that was on a female House Finch in May 2016. With each passing day that I watched her, she became less able to function at the feeder. Both of her eyes were swollen and nearly closed; she would flutter until she happened to land on a branch, or the feeder, or the ground. It was clear to me that she couldn’t see well enough to fly and perch. For her, feeding became nearly impossible due to her poor eyesight. Eventually, she stopped visiting my back garden.
For what it’s worth, the other eye of the finch I’ve observed this week is healthy and unimpaired and he’s flying and feeding normally. Additionally, most birds aren’t afflicted by this disease; continent-wide, American Goldfinches (which I only see in late winter) and a few others have been impacted.
What to do? Well, there’s really nothing I can do to help individual birds. They might recover on their own, but more likely, they’ll starve or become prey for someone else once they’re so blinded that they cannot feed and fend for themselves. I am wiping the feeding stations on the feeder each evening with a diluted bleach/water solution, and that’s one easy way to keep the feeder clean. Feeders should be washed once-per-month, though I have to admit that I don’t do that as regularly as I should; I should make that change. Other tips for healthy bird feeding include regularly raking or sweeping the area underneath feeders and spreading feeders throughout the garden so that birds aren’t crowded. Always, if you catch a sick bird, contact a wildlife rehabilitator in your area–he/she will have the expertise to care for the sick bird.
While I certainly subscribe to the dictum of letting nature take its course, we gardeners and bird watchers can help our wild ecosystem partners thrive by simple changes in our gardening and bird-feeding practices. Let’s take care of our wild birds!