Canker is an infection of the mouth, throat and crop caused by the single-celled parasite Trichomonas gallinae. It is also called trichomonosis or trichomoniasis. The classic sign is yellow-white, cheesy lumps inside the beak or throat, often with drooling and difficulty swallowing. A vet confirms it by looking at a swab under the microscope, and it is treated with anti-protozoal drugs such as carnidazole or metronidazole.
Please note: this article is general information and is not a substitute for advice from an avian vet or a licensed wildlife rehabilitator. If you have found an injured or sick bird, contact a vet or your local rescue (see our list of pigeon-friendly rescue centres).
How common is canker?
The University of Florida’s extension guide calls trichomoniasis the most common disease of pigeons and estimates that around 80 per cent of pigeons carry the organism. Most carriers show no signs. Disease tends to appear when a bird is stressed by other illness, parasites, overbreeding or poor conditions, or when it meets a more harmful strain.
How canker spreads
- From parent to squab, through crop milk and regurgitated food. The same guide notes squabs of about 10 to 24 days old are often worst affected.
- Through shared drinking water, baths and feeders.
- Between wild birds at garden feeders.
Signs of canker
- Yellow, white or tan cheesy plaques in the mouth, throat or on the roof of the mouth
- Drooling, repeated swallowing or stretching the neck
- Bad smell from the beak
- Trouble closing the beak
- Watery eyes if lesions are near the sinuses
- Weight loss, fluffed feathers and lack of interest in flying
- In squabs, a swelling at the navel
Large lesions can block the throat and kill a bird by starvation or suffocation, so canker needs treating promptly.
Diagnosis
Other conditions can look similar, including pigeon pox, vitamin A deficiency and candida (yeast). Merck Veterinary Manual explains that canker is confirmed by finding the moving parasites in a wet mount from a swab of the mouth or crop.
Treatment
Merck lists carnidazole, metronidazole and dimetridazole as treatments used in pigeons. Doses and products differ by country and some are prescription-only, so get the dose from a vet. Do not try to pull plaques out. They can be attached to living tissue and bleed heavily.
A bird with a sore throat may not eat enough. A vet or rescue may show you how to crop-feed until it can swallow normally.
Prevention
- Clean and refill drinkers daily. Merck recommends cleaning feeders and waterers often, and removing garden feeders for about two weeks after an outbreak, cleaning them with a 10 per cent bleach solution.
- Quarantine new birds. The University of Florida suggests 30 days.
- Avoid overcrowding and reduce stress.
- Separate birds that keep relapsing from the breeding loft.
- Provide clean water rather than stagnant sources.
When to see an avian vet or contact a rescue
See a vet or contact a rescue if a pigeon has:
- any lump or cheesy patch in the mouth or throat
- difficulty swallowing or keeps dropping seed
- a squab that is not gaining weight
- breathing difficulty
FAQ
Is canker the same as trichomonosis?
Yes. Canker is the fanciers’ name for trichomonosis in pigeons.
Can people catch canker?
No. Trichomonas gallinae infects birds. It is a different organism from the human Trichomonas.
Can my dog or cat catch it?
It is a bird parasite. Birds of prey can catch it from eating infected pigeons.
This guide is general information. If a bird is injured or seriously ill, contact an avian vet or a wildlife rescue as soon as you can.
Sources
- Merck Veterinary Manual: Trichomonosis in birds (opens in new tab)
- University of Florida IFAS: Pigeon canker (VM032) (opens in new tab)
- Bacterial and parasitic diseases of Columbiformes (Vet Clin Exot Anim, via PMC) (opens in new tab)
Last reviewed: 21 October 2026
Last updated 1 November 2026 · Health