Chaffinch Welfare and Garden Bird Finch Disease

Chaffinches and other finches in the UK and Europe are facing a novel disease crisis from trichomonosis, a parasitic infection transmitted at bird feeders.

Key Facts

Trichomonosis caused a major greenfinch and chaffinch population crash from 2005 onwards
The disease causes lesions in the throat making it impossible to swallow food
An estimated 35% of UK greenfinch population has been lost since the disease emerged
Infected birds appear lethargic, fluffed up, and regurgitate food at feeders

Welfare Considerations

Trichomonosis is caused by the parasite Trichomonas gallinae and causes severe suffering. Infected birds develop caseous plaques in their mouths, throats, and crop that prevent swallowing. They starve to death over days or weeks while continuing to try to feed. The disease is transmitted through contaminated saliva at shared bird feeders and water baths. Cleaning feeders and water baths regularly with dilute disinfectant solution is highly effective at reducing transmission. Affected birds should be reported to disease monitoring schemes and do not need to be collected as the disease is not transmissible to humans or pets. Temporarily removing feeders during peak summer transmission periods reduces disease spread.

What You Can Do

Clean bird feeders every 2 weeks with dilute disinfectant and rinse thoroughly
Change water in bird baths daily during summer months
Remove feeders temporarily if you see sick birds feeding at them
Report sick finches to the BTO Garden Wildlife Health project
Space multiple feeders apart to reduce bird crowding and contact at feeding stations