Highly pathogenic avian influenza (HPAI) has been circulating in North America since 2022, and California has had ongoing activity in wild birds, marine mammals, domestic cats, dairy cattle, and periodic backyard and commercial poultry flocks since then, including detections in several counties in early 2026. It's a serious disease for the species it hits hardest, but its risk isn't evenly distributed across birds, and it's worth understanding where the real risk lies before deciding what to do about it.

Who's actually at risk

• Waterfowl (ducks, geese, gulls) are the primary reservoir and often carry the virus without symptoms, though the current strain does sometimes sicken or kill them too.
• Raptors (hawks, eagles, owls) are highly susceptible, typically from eating infected prey. Bald Eagles in particular have been hit hard nationally.
• Domestic poultry are extremely vulnerable, with mortality rates approaching 100% in affected flocks.
• Songbirds and typical feeder visitors (finches, sparrows, titmice, jays) are at consistently low risk. In national surveillance data, songbirds account for only a small fraction of documented wild bird cases, and there's no evidence they meaningfully spread the virus to each other or to poultry.

There is currently no official recommendation to take down feeders because of avian flu, unless you also keep backyard poultry.

Regular feeder hygiene (cleaning every two weeks, more often if you see sick birds) remains the most useful thing you can do, both for avian flu and for the other diseases that spread at feeders.

The concern isn't your poultry catching it from songbirds at a feeder, it's wild waterfowl or their droppings coming into contact with your flock.

Keep feeders and water sources for wild birds away from your poultry's food, water, and living area, and consider removing feeders entirely if there's been a confirmed detection near you. 

The California Department of Food and Agriculture's biosecurity guidance has the full list of precautions for flock owners.

If you've ever seen a House Finch at your feeder with red, swollen, or crusty-looking eyes, that's almost certainly avian conjunctivitis, caused by a bacterium called Mycoplasma gallisepticum. It's extremely common, spreads easily between birds sharing a feeder (tube feeders in particular, since birds perch close together), and while it's most associated with House Finches, it's been documented in goldfinches and other feeder species too.

Signs of House Finch eye disease

Swollen, red, watery, or crusted eyes, sometimes bad enough that the bird has difficulty seeing. Affected birds often look listless, rub their eyes against a perch, or stay at a feeder longer than a healthy bird would, which is part of why it spreads so efficiently there.

Take the feeder down immediately, discard the seed, clean the feeder thoroughly with a diluted bleach solution, and leave it down for one to two weeks before putting it back up. This gives the local finch flock time to disperse instead of continuing to reinfect each other at the same feeder, the same "sick bird at a feeder" protocol covered in our Feeding Birds Responsibly guide.

House Finch eye disease isn't known to infect humans or pets, so the main reason to act quickly is simply to stop it from spreading to more birds while it's active in your yard.

Salmonellosis is the single most common disease spread at bird feeders, caused by Salmonella bacteria in droppings that contaminate shared seed and feeding surfaces. It affects a wide range of feeder birds, especially House Sparrows, goldfinches, and Pine Siskins, and California has seen outbreaks tied specifically to feeders, including a notable 2021 die-off in the San Francisco Bay Area and periodic outbreaks in the Sierra during "irruption years," when large numbers of Pine Siskins move through in search of food.

What to look for

Sick birds often look puffed up, fluffed, and unusually lethargic, sometimes sitting still at a feeder even as other birds flee an approaching person or predator. Unlike House Finch eye disease, there's often no obvious visible symptom beyond the behavior itself, which is part of why sudden deaths at a feeder are sometimes mistaken for poisoning.

What to do

Same protocol as House Finch eye disease: take feeders down, discard the seed, clean thoroughly with a diluted bleach solution, and leave them down for one to two weeks. Unlike House Finch eye disease, salmonellosis can spread to humans and pets, so wash your hands thoroughly after handling feeders during a suspected outbreak, and keep cats and dogs away from sick or dead birds.

A few other diseases show up at feeders less often but are worth being able to recognize:

Trichomoniasis 

Trichomoniasis is a parasite that mostly affects Mourning Doves, one of the most common birds in the Conejo Valley, along with the Cooper's Hawks and other raptors that eat them. It causes sores in the mouth and throat that make it hard to swallow.

What to look for:

Infected birds often drool, gape, or shake their head trying to clear their throat, and may have trouble swallowing or regurgitate food. Sick birds tend to sit fluffed up and still near feeders or water, sometimes letting you approach much closer than a healthy bird would. In advanced cases you may see yellowish, cheese-like sores in the mouth, though this is usually only visible with a bird in hand, not from a distance at a feeder. 

What to do:

Trichomoniasis is not known to spread from wild birds to people. If you see a bird showing these signs, take feeders down for a week or two and clean them thoroughly with a diluted bleach solution before refilling.

Aspergillosis is a fungal infection birds develop from breathing in mold spores that grow on damp or old seed. It's another reason the basic feeder hygiene covered in our Feeding Birds Responsibly guide matters, keeping seed dry and fresh prevents it from ever taking hold. 

What to look for:

Aspergillosis doesn't cause a visible mouth sore like trichomoniasis does, which makes it harder to spot. Infected birds show labored breathing and tail-bobbing with each breath, along with weight loss and lethargy, but these signs can look like general sickness from a distance. 

What to do:

Aspergillosis can spread to people, though this is rare from wild birds. Most human cases come from pet birds, where a person is breathing the same air as a sick bird in an enclosed space. If you see a bird showing these signs, take feeders down for a week or two and clean them thoroughly with a diluted bleach solution before refilling.

Avian pox is a virus that causes wart-like growths on a bird's face, legs, or feet. It's visually distinctive and spreads both through direct contact between birds and, like West Nile, by mosquitoes.

What to look for:

Wart-like, crusty growths on the featherless parts of a bird, typically around the eyes, beak, and legs. In some cases the growths can interfere with eating, breathing, or vision, depending on where they form. Doves, House Finches, and House Sparrows are commonly affected feeder visitors.

What to do:

Avian pox isn't known to spread to humans or pets. If you see a bird with these growths, take feeders down for a week or two and clean them thoroughly with a diluted bleach solution before refilling, the same protocol as the other feeder-spread diseases on this page.

West Nile virus spreads through mosquito bites and circulates between birds and mosquitoes, though most infected birds show no visible signs at all. Corvids (crows, scrub-jays) and raptors are among the species most likely to become seriously ill or die from it, while most songbirds carry the virus without obvious symptoms.

What to look for: A sick bird with West Nile virus may appear weak, uncoordinated, or unable to fly. Because visible signs are unreliable and easy to confuse with other illnesses, the more useful thing you can do is reduce mosquito breeding around your home rather than trying to identify the disease in a bird by sight. See our full guide on Mosquitoes, West Nile Virus, & Your Yard for how to manage standing water safely, including options that are pet- and wildlife-safe like mosquito dunks and the DIY mosquito trap.

What to do: If you find a dead bird you suspect died of West Nile virus, especially a crow, jay, raptor, or other larger bird, report it to the California Department of Public Health's dead bird reporting system rather than handling it directly.

Finding a dead bird in your yard is common and usually not cause for alarm, most deaths are unrelated to the diseases covered on this page. Still, it's worth knowing the basic safety steps and when a report is actually useful.

Don't handle it with bare hands. Use a shovel, an inverted plastic bag, or gloves to move it. Double-bag the bird and dispose of it in the trash, or bury it. Wash your hands thoroughly afterward, even if you wore gloves.

Keep pets away. Cats and dogs can pick up several of the illnesses on this page from mouthing or eating a dead bird. If a pet does have contact with one, contact your veterinarian.

When to report it:

• A sick or dead raptor, waterfowl, or other wild bird, especially in numbers or alongside other unusual mortality, report it to the California Department of Fish and Wildlife using their Wildlife Mortality Reporting Form.
• A dead crow, jay, raptor, or other bird you suspect died of West Nile virus, report it through the California Department of Public Health's dead bird reporting system.
• Sick or dead domestic poultry, ducks, or pet birds, call the CDFA's hotline at (866) 922-2473.

When it's not a rescue situation: A single dead adult songbird found at a feeder is common and doesn't usually need to be reported; the exceptions above are specifically about disease surveillance. See our FAQ for what to do if you find an injured or orphaned bird instead.

Several of these diseases, along with the sick or weakened birds they cause, put roaming outdoor cats at risk too, whether from catching and eating an infected bird or from contact with droppings and contaminated feeder surfaces.

Keeping cats indoors, or giving them supervised outdoor time in a catio, protects both your cat and the birds in your yard. See our page on Keeping Birds, Cats, and Local Wildlife Safe for the full picture.

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