Skip to main content

Conjunctivitis in finches (Mycoplasmosis)

Conjunctivitis is a medical term to describe inflammation of the membrane that covers the front of the eye and lines the inside of the eyelids. The disease in wild birds was first identified in 1994 when house finches in Washington D.C. were reported with severe conjunctivitis with swollen eyes with runny or crusty discharges. The cause of this specific conjunctivitis in finches is a specific strain of bacteria called Mycoplasma gallisepticum. The disease is also called house finch eye disease, Mycoplasmal conjunctivitis or Mycoplasmosis. This disease is most common in house finches but has also been reported in purple finches, American goldfinches and evening grosbeaks. It has been found in house finches in nearly all states east of the Rocky Mountains. There are a few sporadic reports annually of conjunctivitis in finches in Wisconsin.


The bacteria are transmitted between birds through the infective discharge from the eye. It is easily spread where birds congregate at roost sites, feeding areas, bird feeders and bird baths. Tube-type bird feeders are especially risky because the discharge from the eyes can easily be left on the openings of the feeders and transmitted to the next bird that arrives. The bacteria can also survive for short periods on contaminated materials such as dust, litter, feathers, bird feeders, boots and clothing.


Affected birds have red, swollen eyes with a clear discharge. As the disease worsens, birds can develop a crusty layer around the eyes and the eyes can become swollen shut. The feathers around the eyes may become wet and matted and the birds will look fluffed out and become inactive.


Preventing transmission to healthy birds is the best method of management. The public can take simple precautions to reduce the risk of transmission of mycoplasmosis in wild birds.

  • Clean feeders, feeding areas and birdbaths using a 10% bleach solution.
  • Remove seed hulls under bird feeders.
  • Move feeders occasionally to prevent the buildup of excrement underneath the feeder.
  • Add additional feeders to reduce overcrowding and contamination.
  • Keep seeds and food dry.
  • Change the water in birdbaths regularly.
  • If a sick or dead bird is found near a feeder or birdbath, remove the feeder or birdbath, wash and disinfect it using the 10% bleach solution and wait at least a week before putting it back up. If possible, move it to a new location.

If you find a group of dead birds, contact the DNR Wildlife Switchboard by emailing or calling 608-267-0866. You will need to leave a message for the switchboard staff to return your call. In your message, please include the number of animals, the species (such as goldfinch), if they were sick or dead, the specific location where you saw them, including the county and your contact information.


The bacteria that causes finch conjunctivitis does not infect people.