Avian pox is a viral disease that can affect many species of wild and domestic birds. It often appears as wart-like growths on unfeathered areas of a bird’s body, including the skin around the eyes, the base of the bill, the legs, and the feet.

Some cases are mild and resolve over time. More serious infections can interfere with a bird’s ability to see, eat, breathe, or escape predators. Knowing what to watch for and responding promptly can help reduce opportunities for the virus to spread at your Colorado Springs feeding station.

What Is Avian Pox?

Avian pox is caused by a group of viruses known as avipoxviruses. Different strains affect different groups of birds, and the disease has been documented in many wild bird species.

Avian pox is not the same disease as human chickenpox, and it is not avian influenza.

The severity of an infection depends partly on the location, size, and number of lesions. Small external growths may eventually regress or fall away. Severe infections can lead to secondary infections, weakness, difficulty feeding, impaired vision, breathing problems, or death.

What Does Avian Pox Look Like?

Avian pox can appear in two primary forms.

Cutaneous or “Dry” Avian Pox

This is the more commonly observed form. It causes raised, wart-like or crusty growths on areas without feathers, such as:

• Around the eyes
• At the base or corners of the bill
• On the eyelids
• On the legs, feet or toes
• Around other exposed areas of skin

Growths may begin as small pale or yellowish bumps before becoming larger, darker or more crusted. Their appearance can vary considerably.

Diphtheritic or “Wet” Avian Pox

This form produces plaques or lesions inside the mouth, throat or respiratory tract. These lesions may not be visible from a distance but can interfere with eating and breathing.

Possible signs include:

• Difficulty swallowing
• Difficulty breathing
• Open-mouth breathing
• Discharge around the bill
• Weakness or reduced activity
• Difficulty eating despite remaining near food

A bird may have one form or a combination of both.

Avian Pox or House Finch Eye Disease?

Avian pox can be mistaken for House Finch eye disease when lesions develop near the eyes. However, their typical appearances are somewhat different.

Avian pox is more likely to produce defined, wart-like growths or raised lesions. Mycoplasmal conjunctivitis is more likely to cause red, swollen, watery or crusted eyes without a distinct wart-like growth.

It is not always possible to distinguish these illnesses by observation alone. Injuries, tumors, and other infections can also cause swelling or unusual growths.

Fortunately, the appropriate first steps at a backyard feeding station are similar: remove the affected feeders, clean and disinfect the feeding area, and give the birds time to disperse.

Learn more on our House Finch Eye Disease page.

How Does Avian Pox Spread?

Avian pox can spread in several ways:

• Bites from mosquitoes and other biting insects
• Direct contact between infected and uninfected birds
• Contact with contaminated feeder ports, perches and other surfaces
• Contact with contaminated food or water
• Virus entering through small breaks in the skin

Mosquitoes can pick up the virus while feeding on an infected bird and then carry it to another bird. Shared feeders may also contribute when birds rub affected skin against ports or perches and leave infectious material behind.

Feeders do not create avian pox, but any location where birds gather can provide additional opportunities for infection to move between individuals.

What Should I Do If I See an Affected Bird?

If a bird with suspicious growths or lesions has been using your feeding station:

• Take down the affected feeders. If birds move regularly among several feeders in the same station, remove all of them.
• Discard the remaining food. Do not return potentially contaminated food to its original container or scatter it elsewhere.
• Clean the surrounding area. Rake or sweep up seed, shells, droppings and other debris beneath the feeders.
• Wash and disinfect the feeders. Remove all visible debris first. Then disinfect them using approximately one part household bleach to ten parts water.
• Rinse thoroughly. Allow every feeder component to dry completely before using it again.
• Leave the feeders down for approximately two weeks. This encourages birds to disperse and reduces repeated contact with contaminated surfaces.
• Continue watching the area. If another affected bird appears after the feeders return, repeat the process.

Do not mix bleach with vinegar, ammonia or any other cleaning product.

Should I Remove My Bird Bath?

If the affected bird has used your bird bath, empty the bath and clean and disinfect it thoroughly. Rinse it carefully before returning it to service.

Avian pox can be carried by mosquitoes, but that does not mean you must permanently remove your bird bath. Mosquitoes need standing water long enough for their larvae to develop. Frequently changing the water, scrubbing the basin and keeping the bath well maintained make it less suitable for mosquito breeding while continuing to provide birds with valuable clean water.

Also check your yard for water that remains undisturbed in clogged gutters, buckets, saucers, tires, tarps, and other containers.

Learn more in our Bird Baths in Colorado Springs Guide.

Should I Try to Treat or Remove the Growths?

Do not pull, cut, scrape, or otherwise attempt to remove a growth from a wild bird. This can cause bleeding, pain, secondary infection, and additional injury.

Do not add antibiotics, medications, or home remedies to bird food or drinking water. Antibiotics do not treat viruses, and uncontrolled medication can expose healthy birds and other wildlife to inappropriate substances.

Most wild birds are protected by law and may only be captured and treated by properly licensed professionals. Do not attempt to capture an affected bird unless a licensed wildlife rehabilitator provides instructions.

If the bird cannot fly, is unable to eat, has difficulty breathing, or appears to be in immediate danger, contact a licensed wildlife rehabilitator for guidance.

Can Birds Recover From Avian Pox?

Birds with mild external lesions may recover, with the growths gradually regressing or falling away over several weeks or months. Recovery is less likely when lesions interfere with vision, breathing, standing, or feeding.

Open or damaged growths can also become infected with bacteria or fungi. Even when the poxvirus itself is not fatal, an affected bird may become more vulnerable to starvation, severe weather, and predators.

How Can I Reduce Disease at My Feeders?

There is no guaranteed way to prevent avian pox, particularly because mosquitoes and direct contact between wild birds can transmit it. Good feeding practices can still reduce contamination and crowding.

• Clean feeders regularly.
• Choose feeders that can be completely disassembled.
• Scrub food ports, perches, seams and crevices carefully.
• Replace wet, moldy or contaminated food promptly.
• Spread feeders apart to reduce crowding.
• Clean the ground beneath feeding stations.
• Change bird-bath water frequently.
• Eliminate neglected standing water where mosquitoes can reproduce.
• Wash your hands after handling feeders, baths or bird waste.
• Monitor birds for changes in appearance or behavior.

For routine cleaning, follow the instructions provided for your feeder. Depending on the feeder materials, it may be cleaned with hot soapy water or a solution of one part white vinegar to ten parts water. Rinse thoroughly and allow it to dry completely before refilling it.

If a sick bird has used the feeder, follow the bleach-disinfection process described above.

Visit our Backyard Bird Care Guide for more information about cleaning feeders, maintaining bird baths and keeping food fresh.

Help Scientists Track Bird Disease

Photographs can help document unusual lesions and symptoms, but take them from a safe distance with a camera or zoom lens. Do not approach or handle the bird simply to obtain a better photograph.

Participants in Project FeederWatch can report birds showing signs of disease. These observations help researchers monitor when and where illnesses occur.

A Sick Bird Is a Signal to Pause

Seeing a bird with avian pox can be upsetting. Temporarily removing feeders may feel difficult, but a short pause reduces crowding and gives you an opportunity to clean and disinfect the entire feeding station.

Our team at Wild Birds Unlimited of Colorado Springs can help you choose easy-to-clean feeders, find replacement parts, and select appropriate cleaning supplies. We cannot diagnose or treat wildlife disease, but we are always happy to help you maintain a cleaner and healthier feeding station.

 

Additional Resources:

Cornell Wildlife Health Lab: Avian Pox
Project FeederWatch: Sick Birds and Bird Diseases
U.S. Geological Survey: Avian Pox
Wild Birds Unlimited of Colorado Springs: Bird Health
Wild Birds Unlimited of Colorado Springs: House Finch Eye Disease