Should we be feeding the birds?

Around half of all British households put food out for birds. The Big Garden Birdwatch may tempt nature lovers to top up bird feeders and tables to lure more birds to their gardens to count them. But there is increasing concern over feeding birds.

What’s the problem?

A growing body of scientific evidence suggests that feeding birds can spread disease, particularly among finches. The greenfinch was put on the red list in 2021 after suffering a population crash of 63% since 1993 after a severe outbreak of trichomonosis. This emerged in 2005 and rapidly became endemic in greenfinch and chaffinch populations. An estimated 6m greenfinches and chaffinches have died. Although greenfinch numbers have begun to recover recently, goldfinches have now been found dead from the disease. The disease is caused by the parasite Trichomonas gallinae and affects sociable, flocking birds in particular and is spread through infected saliva in water and seeds (although not to humans). Some garden birds, such as dunnock, appear not to be affected.

There are other potential drawbacks to excessive bird-feeding. A recent study found that feeding birds changes the local phosphorus cycle – potentially adding extra nutrients to the environment which can favour some plants over others and reduce biodiversity and damage wild habitats such as woodlands.