Diseases at bird feeders: what to look for and when to take the feeders down

The short answer

• When you see a sick or dead bird at your feeders, take every feeder down for two weeks, clean everything, and rake up the spilled seed underneath.
• Salmonellosis is the outbreak most likely to hit a seed feeder, and it tracks winters when pine siskins irrupt south in large flocks.
• House finch eye disease produces crusted, swollen, often closed eyes and spreads on the feeder ports birds press their faces against.
• Trichomonosis kills doves and finches by blocking the throat, and it spreads through shared water as readily as through shared seed.
• Follow your state or provincial wildlife agency's current advice, which is the only source that knows what is circulating near you this month.

A feeder does one thing that nothing in a natural landscape does: it puts dozens of birds, repeatedly, on the same few square inches of surface, in the same spot, day after day. That is what makes it a good place to watch birds and a good place for a pathogen to move. None of the diseases below are caused by feeding. All of them are accelerated by it.

The good news is that the response is almost always the same, and you do not need a diagnosis to act on it.

Salmonellosis#

What you see. A bird sitting fluffed and half asleep, often on the ground below the feeder, letting you approach far closer than it should. It may pick at seed without swallowing. Death follows fast, so many people see a dead bird before they see a sick one. Finches, and siskins in particular, are the usual casualties.

How feeders spread it. Salmonella passes in droppings. A tray feeder where birds stand in their own waste, a hopper with a wet floor, and the ground under any feeder are all reservoirs. Wet, moldy seed is the ideal medium, which is why this is a wet-winter and early-spring problem more than a January cold snap problem.

The pattern to know. Salmonellosis outbreaks track irruption years. When pine siskins push south in large numbers, they arrive as big, hungry, tightly packed flocks, often already stressed, and they crowd nyjer and sunflower feeders in numbers a yard never normally sees. Look at how many species overlap on those two seeds:

Top top-tier favorite Yes eats readily Some takes occasionally Rare rarely No not a feeder food

Everything in that table can end up at the same tube in the same hour. In an irruption winter, tighten your cleaning interval before you see a problem, not after.

Response. Feeders down for two weeks, full clean, ground raked. If your area is in a declared outbreak, keep them down as long as the agency asks.

House finch eye disease (mycoplasmal conjunctivitis)#

What you see. One or both eyes red, swollen, watery, then crusted shut. The bird is often otherwise alert but sits still and stays late at the feeder because it cannot see well enough to do anything else. Blind birds do not starve directly, they get taken by cats and hawks or hit by cars.

How feeders spread it. By direct contact with surfaces. Birds press their faces to feeder ports, and Mycoplasma gallisepticum transfers from the port to the next bird's eye. Tube feeders with small ports are the classic vector because the bird's face touches the plastic on every visit.

Which birds. House finches most of all, hence the name. Goldfinches, purple finches and other finches also get it.

Response. Same two-week takedown and clean. When you restart, this is the disease that most rewards a change of feeder style: switch to designs where birds do not push their heads into a port, spread the flock across more feeding stations, and keep the cleaning interval short. Our cleaning schedule tool will set an interval from your weather and traffic.

Trichomonosis#

What you see. A bird that looks like it is trying to swallow and cannot. Wet, matted feathers around the beak, food dropped repeatedly, laboured breathing, obvious weight loss over days. Doves and pigeons are the classic hosts, and finches are hit hard where it has spread into songbird populations.

How feeders spread it. The parasite lives in the mouth and throat and is passed through saliva on shared food and shared water. This is the disease that makes bird baths part of the problem: a contaminated bath can move it faster than a seed tray. Adults also pass it to their young by regurgitation, so a summer outbreak spreads through nests.

Response. Take down feeders and the bath for two weeks. Water is not optional to clean here. When you restart the bath, move to the maintenance rhythm in bird baths and water, which for summer means a change every two to three days.

Avian pox#

What you see. Wart-like growths, usually on unfeathered skin: around the eyes, at the base of the beak, on the legs and feet. Mild cases look like a rough gray or yellowish lump. Bad cases distort the beak or close an eye. The bird often behaves normally at first.

How feeders spread it. Mostly by contact with contaminated surfaces, especially rough ones that hold material in cracks, and by biting insects. Wooden perches and porous, weathered plastic hold virus longer than smooth metal or glass.

Response. The two-week takedown applies. This is also the disease that argues hardest for replacing split, roughened perches rather than living with them, which is one of the checks in feeder repair and maintenance. Do not try to treat a bird yourself; it is illegal for native species and pointless without training.

Highly pathogenic avian influenza#

What you see. Neurological signs are the giveaway: a bird twisting its neck, unable to hold its head straight, walking in circles, tremors, or sudden death with no other explanation. In practice, backyard feeder watchers are far more likely to see this in waterfowl, gulls, crows or a raptor than in a chickadee.

How feeders relate to it. Songbirds at seed feeders are not the main carriers. The risk concentrates in waterbirds and the raptors and scavengers that eat them. The real feeder connection is proximity to poultry: if you keep chickens or ducks, wild birds around the coop are a serious biosecurity problem, and feeders and baths near a coop should come down and stay down.

Response. If you keep poultry, do not feed wild birds. If you do not, follow your state or provincial wildlife agency, which will say plainly whether feeders should come down in your area right now. That guidance changes with the season and the outbreak map, and it is the only answer that reflects your county rather than the internet.

Reading the signs: a quick sort#

That last row matters. A soaked bird in April, a juvenile with patchy head feathers in August, or an adult in heavy molt in late summer all look alarming and are all normal.

Handling dead birds safely#

1. Put on disposable gloves, or invert a plastic bag over your hand as a glove.
2. Pick the bird up, pull the bag back over it so the bag is now right side out around the body, and seal it.
3. Put that bag inside a second bag and seal that too. Place it in household waste, or follow your agency's instructions if they differ.
4. Wash your hands with soap and water. Disinfect any tool you used.
5. Keep dogs and cats away from the carcass and the ground where it lay.

Report before you dispose if you find several dead birds in a short window, or any dead waterfowl, gull, crow or raptor. Clusters are what state and provincial agencies want to hear about, and a single reported cluster is often what triggers a regional advisory.

Prevention that actually reduces risk#

Cleaning is the obvious half. The layout is the half people miss.

• Clean on a schedule, not on appearance. Every two weeks in mild dry conditions, weekly in heat, damp or heavy traffic. Method and dilution in how to clean a bird feeder.
• Never top up over old seed. The bottom layer is where damp, mold and droppings collect. Empty, then refill. See moldy seed for what grows down there.
• Spread the birds out. Two feeders 15 ft apart carry the same crowd at half the density of one feeder. In an irruption winter, three is better than two.
• Move the station occasionally. Droppings and hulls build up in the ground beneath a feeder. Shifting the pole 10 ft once or twice a year resets that.
• Cut the hull layer. Hull-free seed leaves nothing on the ground to rot. That is one of the arguments for sunflower hearts beyond the tidiness.
• Rake underneath. Ten minutes with a rake in early spring removes the single largest reservoir in most yards.

Restarting after a takedown#

Do not put four feeders back on day fifteen. Hang one, fill it with fresh seed from a sealed container, and watch it for a week. If birds look healthy, add the rest one at a time over the following week. If a sick bird appears again, everything comes down for another two weeks and you check your agency's page before trying again.

Birds do not need your feeder to survive. Two weeks with no feeder in a yard that has decent native cover and natural food costs the local flock almost nothing, and it is the most effective single action available to you.

Frequently asked questions#

Should I take my bird feeders down if I see a sick bird?

Yes. The standard response is to take every feeder and bath down for two weeks, run them through the full clean in how to clean a bird feeder, and rake up the seed and droppings on the ground underneath. Two weeks disperses the flock and breaks the transmission chain. Feeding birds is not necessary for their survival in most of North America, so the cost of a pause is close to zero and the benefit is real.

What does a bird with salmonellosis look like?

Fluffed up, slow and unusually tame. A sick bird sits with feathers puffed, eyes half closed, often on the ground below the feeder, and lets you walk right up to it. It may keep trying to feed without swallowing much. Salmonellosis kills quickly, so the first sign for many people is a dead bird under the feeder rather than a sick one on it. Pine siskins and goldfinches are the classic victims, especially in a winter when siskins have moved south in numbers.

Can I catch anything from my bird feeder?

Salmonella bacteria can pass to people and to pets, usually through hands or through a dog or cat that picks up a dead bird. Handle feeders as you would raw chicken: wash your hands afterwards, do not clean feeders in the kitchen sink, and use a dedicated bucket and brush outdoors. Highly pathogenic avian influenza very rarely infects people, but the same precautions apply. Keep dogs and cats away from sick or dead birds entirely.

Do I need to stop feeding because of bird flu?

For most backyards, no. Songbirds at seed feeders are not the main carriers of highly pathogenic avian influenza; waterfowl, gulls and raptors are the birds usually involved. The advice changes if you keep poultry, in which case wild birds near a coop are a genuine risk and feeders should come down. It also changes during a local outbreak. Check your state or provincial wildlife agency, which posts current guidance and is the authority to follow.

How do I safely dispose of a dead bird from under my feeder?

Do not touch it with bare hands. Wear disposable gloves or invert a plastic bag over your hand, pick the bird up, turn the bag inside out around it, seal it, put it in a second bag and place it in household waste. Wash your hands thoroughly afterwards. If you find several dead birds in a short period, or any dead waterfowl or raptor, report it to your state or provincial wildlife agency before disposal, because clusters are what agencies track.

How long should feeders stay down after an outbreak?

Two weeks is the working minimum, and it is what most wildlife agencies ask for. Longer if birds are still turning up sick when you put feeders back, or if your agency asks for a longer pause. When you restart, put out one feeder rather than four, use fresh seed, and watch for a week before restoring the full station. Reopening at full capacity puts the same crowd back in the same place, which is what caused the problem.

Sources and further reading

1. National Wildlife Health Center US Geological Survey Wildlife disease surveillance, mortality event reporting and disease fact sheets
2. Bird Feeder Maintenance and Cleaning Cornell Lab of Ornithology, Project FeederWatch Cleaning method, bleach dilution and sick bird guidance
3. Animal and Plant Health Inspection Service US Department of Agriculture Current status of highly pathogenic avian influenza and reporting routes
4. Birds Canada Birds Canada Canadian feeder disease guidance and regional advisories