Outbreaks of disease amongst Greenfinches and other garden birds


Since mid 2005, BirdWatch Ireland has been receiving an increasing number of reports of garden birds dying of a disease called trichomoniasis, caused by the parasitic Trichomonad organism.


The outbreaks in the past two years have been during the late summer and autumn, and there are already signs of an outbreak in 2007.  This disease does not pose a threat to the health of humans, cats, dogs, or indeed any mammal.


Which birds are affected?

Incidences of this disease have increased since May 2007, with many people reporting affected birds in their gardens.  Greenfinches have been the species most frequently affected, but other finch species and House Sparrows are also susceptible to the disease.  Formerly, this disease has been recorded in pigeons and doves, as well as in some birds of prey and gamebirds.


What happens?

The parasite lives in the upper digestive tract of the bird, and its actions progressively block the bird’s throat making it unable to swallow food, thus killing it by starvation.


Birds with the disease show signs of general illness, such as lethargy and fluffed-up plumage, but affected birds may also drool saliva, regurgitate food, have difficulty in swallowing or show laboured breathing.  Finches are frequently seen to have matted wet plumage around the face and beak. In some cases, swelling of the neck may be visible from a distance.


How is it transmitted?

The parasite is vulnerable to desiccation (drying out) and cannot survive for long periods outside the host.  Transmission of infection between birds happens when they feed one another with regurgitated food during the breeding season and through food or drinking water contaminated with recently regurgitated saliva, or possibly from droppings of an infected bird.


What can I do?

Good hygiene practice, specifically the regular cleaning of all feeders, bird baths and feeding surfaces, is an essential part of looking after garden birds and will help to lower the risk to birds of diseases, including trichomoniasis.  To download a special BirdWatch Ireland factsheet giving advice on feeder hygene and what to do if you find dead birds, please click here.


If trichomoniasis is suspected, we recommend that you temporarily stop putting out food and leave bird baths dry for around two weeks, or until sick or dead birds are no longer found in the garden.  This is in order to discourage birds from congregating together, which may increase the potential for disease spread between individuals.


No effective treatment can be administered to birds in the wild, because it is impossible to ensure that the infected individuals receive an adequate dose and that healthy birds do not pick up the medicine.


How can you help us?

If you are finding sick and dead birds in your garden, please help us monitor the spread and intensity of disease outbreaks, including trichomoniasis, in garden birds by telling us what is happening to your garden birds.  You can contact us at or by calling 01-2819878.

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