Wild Bird Diseases
Learn to recognize and prevent avian flu and other diseases in wild birds
Highly Pathogenic Avian Influenza (HPAI) is a subset of the H5N1 "bird flu" virus. HPAI is fatal to hawks, owls and domestic poultry and waterfowl are primary carriers but are generally not killed by it.
It apparently poses very little risk to songbirds (passerines).
Hummingbirds seem pretty safe from it because it is not transmitted
by their saliva into hummingbird feeders.
Documented incidences of HPAI transmission to people are very rare but the Low Pathogenic version seems more easily transmitted.
However, songbirds are still at risk from other diseases transmitted by feces and crowding at feeders.
Salmonellosis is an infection that comes from the Salmonella bacteria. Salmonellosis is spread through droppings which can easily contaminate your birdfeeder and birdbaths.
Aspergillosis is an upper respiratory disease caused by a fungus called Aspergillus. Aspergillus grows in warm moist areas and the spores of the fungus travel through the air and is later inhaled by the birds.
Avian Conjunctivitis aka "House Finch Disease" because the majority of its victims are House Finches. Infected birds show crusty, swollen or runny eyes, in some cases so severe that eyes are swollen shut.
"Mystery Bird Disease" was a widespread killer of birds (especially juveniles) last spring and summer, especially in the East but also appeared in the Northwest. Researchers have not discovered the cause and there’s no guarantee that whatever it was won’t start killing birds again this year.
Mold at feeders is always a problem and causes a variety of illnesses that are not fatal but weaken immune systems.
So, some recommendations:
If you see dead, diseased or disoriented birds on or near your feeders, take them down immediately for at least two weeks!
Clean feeders and bird baths at least weekly with soap and water, then disinfect with a 10 percent household bleach solution. After allowing 10 minutes of contact time, rinse with clean water and allow to air dry. Don't re-use seed from feeders.
Special considerations for hummingbird feeders. They should be emptied and cleaned at least every other day. The sugar promotes rapid growth of dangerous fungi. In cold weather take them in at night and put them out in the early morning. The thermal shock from drinking near-freezing sugar water can kill or disable hummers.
Clean up spilled seed and refuse from under feeders daily. This is a major attractant for other (often undesirable) wildlife such as deer, racoons, rodents and bears.
Don't group feeders together - spread them out.
Avoid wooden feeders, especially large platform feeders where groups of birds are packed close - they are very difficult to clean properly.
In bear country, hang feeders (including hummingbird feeders) at least 10 feet from the ground and well away from the house.
Take feeders in at night to avoid unwelcome visitors!
You can feed birds on the ground but don't concentrate seed in piles. Widely scatter seed with about 1-2 cups per 10'x10' area. This will spread birds out and prevent concentration.
Choose the correct seed for the birds you want to attract. Mixes with high concentration of red millet may be cheaper but very few birds will eat red millet so there's a lot of wastage. White proso millet is a better choice. Quick guides to types of seed:
It's okay to feed hummers with the above caveats.
Also okay to feed songbirds with caution - watch for sick or dead birds.
Links for More Info
A must-read article from Audubon on feeding birds
Dr. Dan takes us through a veritable catalog of diseases that affect songbirds at our feeders. He discusses other causes of morbidity and mortality that are causing population declines in our wild birds.
Also see Dr. Dan's article "Avian flu a small risk to our local songbirds" in the Jackson Hole News & Guide - August 31, 2022.
Common Bird Parasites & Diseases - from Massachusetts Audubon. An overview of common problems found in feeder birds.
Sick Birds and Bird Diseases - from Cornell's FeederWatch website. A bit more detail on three common diseases.
Salmonellosis in Birds - from Seattle Audubon. Specific information on the disease that ravaged bird populations in the West this spring.
Conjunctivitis in Birds - from Cornell's FeederWatch website.
House Finch Eye Disease - from Penn State Extension. Specific information on this common disease.