House Finch Eye Disease

This year I decided to participate in Project FeederWatch. This citizen science program is the perfect outlet for someone who enjoys watching the birds at her backyard feeders, but doesn’t want to bore all her friends and family with a list of birds she has attracted. Project FeederWatch actually wants your data! With their partner the Cornell Lab of Ornithology, they use your data to track birds in Canada and all U.S. states except Hawaii.

Being that the House Finch is a frequent visitor to my feeders in the winter months, it is often included as a bird seen on my weekly FeederWatch sightings list. Each time that I enter the House Finch I am prompted to report if these birds had signs of eye disease. The FeederWatch program has turned out to be a useful tool for scientists to track avian diseases as well as winter movements. 

House Finches were initially found only in western North America. In the 1940’s pet stores across the U.S. started illegally selling House Finches as pets calling them “Hollywood Finches.” Someone in Brooklyn, NY spotted one of the birds in a pet store and reported it to the Audubon Society. To avoid prosecution pet stores stopped selling the House Finches and released them into the wild. The birds that were released continued to breed successfully and spread throughout eastern North America. 

In 1994, participants of Project FeederWatch in the Washington, DC area spotted and reported seeing House Finches with swollen, crusty eyes acting strangely at their feeders. Lab tests were done through the Cornell Lab of Ornithology on some infected birds and found these birds were infected with a parasitic bacterium called mycoplasmal conjunctivitis. This disease had previously been found in poultry as a respiratory disease. Possibly the first House Finch to contract the disease was sharing feed with some of the infected poultry. 

With the help of the participants from Project FeederWatch, scientists from the Cornell Lab of Ornithology have tracked the progression of the House Finch eye disease across the United States since it was first spotted in 1994. Through 1997 the infected birds seemed to be concentrated on the eastern part of the country and through the midwest and into Canada. In 2002 FeederWatch participants began spotting the infected birds in the northwestern states and the disease began progressing down the west coast and finally in 2013 began looping back east into the southwestern states. 

The House Finches afflicted with mycophlamal conjunctivitis have red, swollen, and crusty eyes. In extreme cases the eyes are so swollen the birds are essentially blind making it difficult for them to find food and are susceptible to predators. In many cases, infected House Finches do not die from the disease itself, but from starvation or predation. However, there are some birds who are able to survive mycophlamal conjunctivitis and these are the birds who have continued to spread the disease across the country. 

Over the years the House Finch developed some immunity to the bacteria and to keep up the bacteria evolved to become even more virulent. So, the prevalence of the disease has remained stable. Goldfinches, Purple Finches, and Evening Grosbeaks, have also been sighted with the disease, but it is not as prevalent in these species. 

If you spot infected birds at your feeders, All About Birds has some tips to follow to keep your yard and feeders disease free.

• Clean your feeders at least every month with a diluted bleach solution. Rinse well and allow feeders to dry completely.
• Consider purchasing tube feeders that can be completely disassembled and washed in a diluted bleach solution in the sink or in the dishwasher.
• Rake the area underneath your feeder to remove droppings and old moldy seed.
• Space your feeders widely to discourage crowding among birds.
• If you see diseased birds, take your feeders down and clean them. Wait a few days before putting feeders back up to encourage sick birds to disperse. Contact a wildlife rehabilitator for help with sick birds.
• Read more about House Finch eye disease from Project FeederWatch and All About Birds.

Author: sibirders

SEABROOK ISLAND BIRDERS / “watching, learning, protecting” Seabrook Island Birders (SIB) are residents, renters and guests of Seabrook Island, SC who have an interest in learning, protecting and providing for the well-being of the incredible variety of birds that inhabit Seabrook Island throughout the year. View all posts by sibirders