Fact Sheet: Coping with Diseases at Bird Feeders
Four diseases commonly
affect those bird species that typically use feeders. This is an important
distinction because not all bird species visit feeders.
Salmonellosis is a general term for any disease in animals and people
caused by a group of bacteria known by the Latin name Salmonella. Birds
can die quickly if the Salmonella bacteria spread throughout the body.
Abscesses often form in the lining of the esophagus and crop as part of
the infection process. Infected birds pass bacteria in their fecal droppings.
Other birds get sick when they eat food contaminated by the droppings.
Salmonellosis is the most common bird-feeder disease.
The Trichomonads are a group of protozoan (one-celled microscopic) parasites
that affect a broad variety of animals, including humans. One Trichomonads
species afflicts only pigeons and doves. The popular and widespread Mourning
Dove is particularly susceptible. Birds afflicted with Trichomoniasis
typically develop sores in their mouths and throats. Unable to swallow,
they drop food or water contaminated with Trichomonads that other birds
then consume, thus spreading the disease.
The Aspergillus fungus (mold) grows on damp feed and in the debris beneath
feeders. Birds inhale the fungal spores and the fungus spreads through
their lungs and air sacs, causing bronchitis and pneumonia.
More noticeable than the other diseases, avian pox causes wartlike growths
on featherless surfaces of a bird's face, wings, legs, and feet. The virus
that causes pox is spread by direct contact with infected birds, by healthy
birds picking up shed viruses on food or feeders, or by insects mechanically
carrying the virus on their body. However, not all warty growths on birds
are caused by the avian pox virus.
The Disease Problems
All four diseases can lead to death. Salmonellosis may kill the birds
outright, and pneumonia from Aspergillosis is nearly always fatal. Trichomoniasis
may obstruct a bird's throat. Avian pox growths on the face can become
large enough to impair vision or eating ability and growths on feet and
toes can affect a bird's ability to stand or perch. Thus, sick birds are
more vulnerable to starvation, dehydration, predation, and severe weather.
You can spot sick
birds in a crowd. They are less alert and less active. They feed less
and often cower on a feeder, reluctant to fly. Their feathers look ill-kept.
Despite these obvious symptoms, disease usually is overlooked as a complication
of feeding birds. Certainly, the signs of illness are not as easily noticed
as bright colors and cheery songs; but being inconspicuous does not make
The Precautions against Disease
People who feed birds cannot ignore the disease issue. Eight relatively
easy steps can be taken to prevent or minimize disease problems at feeders.
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
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
4. Keep feeders
clean - Clean and disinfect feeders regularly. Use one part of 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
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 without being affected themselves.
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 birdfeeders will be those in communities where neighbors cooperate
with equal concern for the birds.
The Complete Story
Birds do get sick. Disease is one of many natural processes affecting
wild species. Sick birds do show up at feeders, and other birds can get
sick as a consequence.
Just because bird
feeding is not problem-free does not mean that it is bad or should be
stopped. It does mean you have an ethical obligation not to jeopardize
wild birds. What is called for is intelligent bird feeding. Follow the
precautions listed above, and you can continue to enjoy feeding healthy
Bird feeding seems
like the perfect out-door activity. People can learn a lot while they
enjoy helping birds. As ideal as bird feeding may seem, it carries some
risk for birds that visit the feeders and some responsibility for people
who do the feeding.