The RSPB has advised gardeners to stop using bird feeders filled with seeds and nuts between May and October to reduce the spread of trichomonosis, a parasitic disease that has devastated greenfinch populations. Instead, the charity recommends offering small amounts of mealworms, fat balls or suet, which do not attract large clusters of finches and provide protein for chicks.
Trichomonosis is transmitted through saliva at feeders, and warmer summer months allow the parasite to survive longer, increasing transmission risk. The disease has contributed to a 67% decline in greenfinch numbers since the Big Garden Birdwatch survey began in 1979, with an estimated six million greenfinches and chaffinches dying in recent years. The greenfinch is now on the red list of endangered British birds.
The RSPB's new guidance, 'feed safely and feed seasonally,' also advises removing bird tables and flat-surfaced feeders, where contaminated food can accumulate. Feeders should be cleaned and moved weekly, and water sources changed daily. During winter, seed and nut feeders can be used, but flat surfaces should still be avoided.
Beccy Speight, chief executive of the RSPB, said: 'We’re not asking people to stop feeding, just to feed in a way that protects birds’ long-term health. By making small changes together, we can ensure garden feeding continues to be a positive force for nature.' The charity also encourages planting sunflowers, teasels and ivy to provide natural food sources and support insects for chicks.
The 2023 Big Garden Birdwatch, with 650,000 participants, showed the house sparrow as the most common garden bird, followed by blue tit, starling, wood pigeon and blackbird. The starling has seen a revival, moving up to third place, while the wood pigeon population has increased by 1,003% since 1979.
