Where are all the Chaffinches?

Recently, one of our readers messaged to ask us where all the chaffinches have gone. We have been making enquiries.

Apparently chaffinches have suffered a 35% loss in their numbers over the past decade because of a disease called trichomonosis. While our greenfinches have been hardest hit by this epidemic, suffering a population decline of 65% in the same decade, all finches can be infected.

Trichomonosis is caused by the parasite trichomonas gallinae. An infected bird’s throat swells and it is unable to swallow; it will show signs of general illness such as lethargy, laboured breathing and the fluffed up plumage for which trichomonosis is also known as fat finch disease. The feathers around its mouth may be wet with saliva or regurgitated food. Death is through starvation, sometimes weeks after the initial infection.

We may unwittingly contribute to the spread of this fatal disease because it is passed through contaminated food and drinking water. Bird feeders, bird tables and bird baths need to be cleaned thoroughly and regularly; sweep up spilled food and never put out more than a couple of days’ worth of food or water at a time.

Please don’t think that your garden is safe because you haven’t seen any chaffinches or greenfinches for a while: other garden bird species, including house sparrow, dunnock, great tit and collar doves can be infected and bring the parasite to your bird feeders.