Common Bird Parasites & Diseases

The four diseases that most frequently affect birds that use feeders are: salmonella, trichomoniasis, aspergillosis, and avian pox. All of these diseases are transmitted from one bird to another at feeding stations, especially when overcrowding occurs. Birds are also susceptible to mites and lice. There are many steps you can take to help keep feeder birds and people safe and healthy.

Common Diseases


The most common disease of feeder birds, Salmonellosis is caused by bacteria from the genus Salmonella and often begins as an intestinal-tract infection. Symptoms such as diarrhea, ruffled feathers, and lethargy usually occur. Birds who are showing symptoms usually die in 1 to 3 days.

The disease can spread rapidly at crowded feeding stations as healthy birds eat food contaminated by the droppings of sick birds. Salmonella can be transmitted to people who handle sick or dead birds; always wear disposable gloves when handling infected birds. And wash hands thoroughly after touching a bird feeder or birdbath.


Trichomoniasis is caused by a group of one-celled protozoa and regularly affects many bird species. One strain of the parasite infects pigeons and doves and, in turn, their predators, such as hawks and falcons. In some strains of the disease, birds develop sores in their mouths or throats; because they are unable to swallow, contaminated food is dropped and consumed by other birds, thus spreading the infection.


Aspergillosis is a fungal infection caused by the Aspergillus fungus, which can be found in damp or wet seed mixtures, in birds' nesting materials, or in landfills. Spores inhaled into the lungs and air sacs of birds eventually cause pneumonia and bronchitis. Sick birds experience labored breathing, weakness, and diarrhea, but will continue to take food at feeding stations until they die.

Avian pox

Avian Pox, a viral disease, has been reported to infect 60 species of wild birds. Symptoms of the disease are lesions that form on unfeathered parts of the body such as legs, feet, and eyelids; around the beak; and in the mouth. In some cases, death can occur when numerous sores around the eyes prevent the bird from locating food, but most birds recover from the virus. The virus is spread by direct contact with infected birds at feeders or through bites of mosquitoes that have fed on the blood of sick birds.

Mites and Lice

Some species of mites and lice subsist on bird feathers and skin while others suck blood. Large numbers of blood-sucking mites can cause anemia and death in young birds while a nest heavily infested with feather mites may cause the parents to abandon the eggs or young.

Feather mites: The most common symptom of feather mites in birds such as blue jays, cardinals, and various other species is bald, featherless heads. When they are preening or bathing, the birds are unable to reach the head and neck area and the parasites are able to destroy the head feathers. The black color on the head is due to the skin's exposure to the sun. The feathers will normally grow back in two or three weeks.

Lyme Disease

Ticks can create problems for birds when they attach themselves to skin around the eyes, making it difficult for the bird to locate food. Birds may also transport the deer tick, the vector of Lyme disease, from one place to another, but are not considered a host for the disease.

Situations & Solutions

Preventing Spread of Diseases at Bird Feeders

  • Clean feeders monthly using one part bleach to nine parts warm water. Soak the feeder in the solution for a few minutes, rinse, and air dry.
  • If uneaten food is accumulating in or under feeders, consider using less food or switch to a seed more to the birds' liking.
  • If birds are fighting over space at a feeder, consider adding more feeders to alleviate the congestion that can potentially be responsible for the rapid spread of disease.
  • Store seed in airtight containers to prevent spoilage.
  • Avoid throwing large amounts of food on the ground or alternate ground feeding areas so that uneaten food does not accumulate and develop bacteria or mold.
  • If dead birds are found, stop feeding for a few weeks and thoroughly clean feeders and areas under feeders. Use disposable gloves when handling dead birds.

Dead or Sick Birds

If you see a dead or sick bird near a feeder, the feeder(s) should be removed for two weeks. Wear disposable gloves to remove and clean it outdoors in a bucket, rather than in a kitchen sink. The feeder should be thoroughly dried before refilling with seed.

To dispose of a dead bird, wear rubber gloves or place a plastic bag over your hand to pick up a dead bird. Place the bird in two plastic bags and bury it or place it in the trash. Be sure to keep pets away from bird carcasses and away from the debris area under feeders.

Mites in Homes

When young birds fledge and vacate a nest infested with mites, the parasites must search for new hosts. Occasionally, during their search, they enter homes through air conditioners or windows situated near nests. Don’t panic: the mites cannot survive on humans, feather pillows, or comforters.

If you do have mites in your home, vacuum and wipe up any visible mites. Use detergent and bleach when cleaning areas around windows; the odor should deter others. A barrier of double-sided tape laid on the inside windowsills will also prevent mites from entering houses.