Keep birdfeeders clean to prevent disease

Feeders should be sanitized once a week with a bleach solution.  Photo by J.J. Meyer

Here's my latest column, which is scheduled to run in the Orange County Register on April 9. 

The California Department of Fish and Wildlife has already received more than a dozen reports of the avian eye disease called mycoplasmal conjunctivitis this season. The deadly disease typically affects house finches and goldfinches during spring and summer.

“So far the disease has been confirmed in Sacramento and El Dorado counties, but we’re likely to see it cropping up in new areas,” said Krysta Rogers, senior environmental scientist for the department. “It’s looking like this could be a bad year for the disease.”

Birds infected with conjunctivitis have red, swollen, runny or crusty eyes. In extreme cases the eyes become swollen shut. Infected birds can become blind, and therefore unable to feed. These birds may also appear puffed up and lethargic. While some infected birds recover, many die from starvation, exposure, or predation.

These reports follow on the heels of a salmonellosis outbreak that killed hundreds of songbirds, mostly pine siskins, in Northern California over the recent winter months. Only seven of these dead birds were found in Orange County from the end of December to mid-March, Rogers said.

Vicki Andersen, a licensed songbird rehabilitator from Fountain Valley, took in two of these birds, both pine siskins, which were retrieved from Silverado Canyon. “The birds that came in were very, very sick,” she said. “They appeared emaciated, weak, fluffed up and unresponsive. Both died within a couple of hours.” Because of these symptoms, Andersen attributed the deaths to salmonellosis, though there was no necropsy done on the birds. Pine siskins tend to be particularly susceptible to the disease, she said. Though other species may also develop the disease from close contact with infected pine siskins.

“This was the first time I’ve ever taken in a pine siskin,” said Andersen, who has had a license to rehabilitate songbirds for 15 years at her Songbird Care and Education Center. Pine siskins are small songbirds from the finch family. They are gregarious birds that tend to flock with goldfinches. They are migrants, or winter visitors, to our area. Most have begun their spring migration north, she said.

Because salmonellosis is a bacterial infection spread through food and water contaminated with feces, it has been associated with bird feeders. After this recent outbreak, Rogers said that ideally she’d like to see all bird feeders be taken down permanently. “But since that isn’t likely, at the very least it’s recommended that bird feeders and bird baths be removed for at least three to four weeks and cleaned well.”

The National Wildlife Health Center states that it is possible to prevent or minimize disease problems at bird feeders and recommends the following steps:

1. Give them space – Avoid crowding by providing ample feeder space. Lots of birds using a single feeder looks wonderful, but crowding is a key factor in spreading disease. If birds have to jostle each other to reach the food, they are crowded. This crowding also creates stress, which may make birds more vulnerable to disease.
2. Clean up wastes – Keep the feeder area clean of waste food and droppings. A broom and shovel can accomplish a lot of good, but a vacuum such as you might use in your garage or workshop will help even more.
3. Make feeders safe – Provide safe feeders without sharp points or edges. Even small scratches and cuts will allow bacteria and viruses to enter otherwise healthy birds.
4. Keep feeders clean – Clean and disinfect feeders regularly. Use one part liquid chlorine household bleach in nine parts of tepid water (a 10 percent solution) to disinfect. Make enough solution to immerse an empty, cleaned feeder completely for two to three minutes. Allow to air dry. Once or twice a month should do, but weekly could help more if you notice sick birds at your feeders.
5. Use good food – Discard any food that smells musty, is wet, looks moldy or has fungus growing on it. Disinfect any storage container that holds spoiled food and the scoop used to fill feeders from it.
6. Prevent contamination – Keep rodents out of stored food. Mice can carry and spread some bird diseases.
7. Act early – Don’t wait to act until you see sick or dead birds. With good prevention you’ll seldom find sick or dead birds at your feeders.
8. Spread the word - Encourage your neighbors who feed birds to follow the same precautions. Birds normally move among feeders and can spread diseases as they go. The safest bird feeders will be those in communities where neighbors cooperate with equal concern for the birds.
For more information, go to: www.nwhc.usgs.gov, and wildlife.ca.gov.

Being vigilant about cleanliness is particularly important when it comes to hummingbird feeders. Hummingbirds can pick up a deadly fungal infection called Hummers Candidiasis from dirty feeders. The infection causes a swollen tongue, which causes the birds to suffocate or starve. An infected bird can pass this disease to birds at other feeders. A sugar solution, or nectar, can ferment in direct sunlight in two days and in as little as five days in the shade. If the nectar solution is cloudy or moldy, take it down and clean it thoroughly with a 10 percent solution of white vinegar and hot water. Rise thoroughly and replace with fresh nectar.

Happy Birding!
J.J.