Trichomonosis is a disease caused by a microscopic parasite called Trichomonas gallinae. It mainly affects pigeons, doves, and birds of prey, but since 2005 it has also been found in our greenfinches and chaffinches, which have been hit the hardest. During 2006 and 2007, breeding populations of these birds declined significantly. It has been found in other species such as sparrows, dunnocks, great tits, siskins and bullfinches.

This disease is also known as canker in pigeons and doves, and frounce in birds of prey. While it has long been recognised in captive birds (where treatment is possible), it is very difficult to treat in wild populations.

What does it do?
Trichomonosis affects a bird’s throat and upper digestive tract. Over several days or weeks, lesions develop that make swallowing difficult. Infected birds may show signs such as excess saliva around the beak, difficulty eating, and general weakness. Sadly, this often leads to starvation and death.

How does it spread?
The parasite cannot survive for more than 24 hours outside a host unless conditions are damp. It literally dries out in warm dry conditions. But if its damp it can thrive for a longer time. So if food is allowed to sit in the bottom of feeders without being cleaned out regularly, or food collects on the floor these will allow the parasite to survive. It is most commonly spread:

• Through shared food and water sources
• Via contaminated droppings
• When infected birds drop food that others then eat
• Through direct feeding between birds, normally mates

Greenfinches are starting to show some signs of developing resistance, but chaffinches have not yet shown the same level of resilience. The disease is now present in several countries, including Ireland, Germany, and the Netherlands.

The reason why stopping feeding can be a bigger problem is that it causes bigger flocks of birds to congregate at smaller feeding areas. So imagine if there were 10 feeding sources in an area and 8 were feeders and 2 were natural Say 7 took their feeder down. There would now be 3 sources, 1 feeder and 2 natural. The amount of birds going to these few areas means a higher risk of disease spreading.

How you can help

You can make a real difference by keeping feeding areas as clean and safe as possible:

• Clean bird feeders regularly
• Keep feeding areas dry and free from waste build-up
• Provide fresh tap water daily
• Only put out enough food for one day
• Move feeders occasionally to prevent debris accumulating underneath
• If you notice a sick bird, stop feeding for two weeks and thoroughly clean all equipment, then put back your peanut and suet feeders and slowly bring back seed.

These simple steps can help reduce the spread of infection and protect garden birds.

As always though if you are worried about feeding the easiest thing to do is just not to feed seed. The seed attracts them as this is what they would naturally eat. At this point you can safely feed Suet and dried worms. I also feed peanuts as they do not seem to be attracted to these.