Garden bird feeding provides significant wildlife welfare benefits but can also spread disease if feeders are poorly maintained. Evidence-based best practice maximises benefit and minimises harm.
Garden bird feeding represents one of the most direct positive human impacts on wildlife welfare — millions of birds that would otherwise die from winter cold and starvation are sustained by supplementary feeding. The welfare benefit is measurable and individual. However, poorly maintained feeders concentrate birds and provide ideal conditions for pathogen transmission. Trichomonas gallinae, spread through regurgitated food at feeders, has caused dramatic declines in greenfinch and chaffinch populations — a welfare harm paradoxically caused by the feeding intended to help. Regular feeder cleaning eliminates this risk. The individual welfare benefit of feeding vastly outweighs the disease risk when appropriate hygiene is maintained.