Please, keep bird feeders clean to keep birds healthy

This house finch has an eye disease commonly contracted at dirty bird feeders. CPW urges backyard birders to keep feeders clean.
Colorado Parks and Wildlife Logo

Joe Lewandowski

MONTROSE, Colo. – Backyard birders love their feeders, but when birds get bunched up they can pass around diseases.  You can help prevent diseases through proper use and regular cleaning of bird feeders and bird baths.

A recent observation in the Montrose area of house finches with swollen, crusty eyes sent up warning flags for Colorado Parks and Wildlife biologists for house-finch eye disease.  The disease, also called mycoplasmal conjunctivitis, is slowly spreading across the United States and Colorado birds are at risk. Although house-finch eye disease has not yet been confirmed in Colorado, it is important to remember that this disease and several others are commonly spread at bird feeders and bird baths. Other diseases include salmonellosis, trichomoniasis, avian pox, pigeon paramyxovirus and aspergillosis.

“Watching birds at feeders, especially during the winter, is a great way to enjoy and learn about the beauty of nature,” said Karen Fox, wildlife pathologist for Colorado Parks and Wildlife.  “Unfortunately, bird feeders and bird baths can quickly become contaminated with bacteria, viruses, parasites, and fungi if visited by sick birds. These germs are then spread to other healthy birds visiting the same feeders. Crowding of birds makes it even easier for germs to spread and large numbers of birds can become sick and even die.”

Most bird feeders should be cleaned at least once a month and bird baths at least once a week.  Platform-style bird feeders that allow birds to walk on top of ‒ and defecate on ‒ feed require more frequent cleaning in order to prevent the spread of bacteria like Salmonella. Hanging-style feeders with perches are easier to keep clean; but be sure to clean under the feeders where bird feces and feed accumulate.  Birds feeding off the ground can easily pick up bacteria from feces.

Colorado Parks and Wildlife offers these tips for those with feeders:

  • Clean feeders at least once a month.  Feeders can be washed in the dishwasher or with soapy water; rinse with diluted bleach solution ‒ nine parts water to one part bleach.
  • Clean bird baths and provide clean, fresh water at least once a week.
  • Be sure to dry feeders thoroughly before refilling; always dispose of any feed that gets wet.
  • Use multiple feeders and space them widely to prevent birds from crowding.
  • Sweep or rake-up debris and droppings below feeders so that birds don’t come in contact with waste material. Do not spread seed on the ground.
  • If you see diseased birds, take down your feeders for at least two weeks; then clean feeders thoroughly prior to replacing seed.
  • Wear gloves when handling feeders and wash hands afterward. Some diseases, such as salmonellosis, can cause illness in humans and domestic animals.
  • Pets should never be allowed to play with or consume sick or dead birds.
  • Please contact the nearest Colorado Parks and Wildlife office if you observe sick or dead birds at your feeders.
To learn more about birds and diseases, visit:

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