Putting out bird feeders in gardens is a popular pastime in the UK, with millions of households regularly providing food to attract wild birds. However, the Royal Society for the Protection of Birds (RSPB), the country's largest bird charity, has issued new advice cautioning against feeding birds during the warmer months-from 1 May to 31 October. The charity warns that keeping feeders out during this period could inadvertently help spread a harmful disease among garden birds.
The disease in question is trichomonosis, caused by a parasite that infects the mouth, throat, and upper digestive tract of birds, making it difficult for them to eat, drink, or breathe properly. Infected birds shed the parasite through saliva and droppings, contaminating feeders and food sources. The parasite can also be passed directly to chicks when adult birds regurgitate food. This disease has had a devastating impact on some familiar garden species, particularly greenfinches and chaffinches.
Greenfinches were once a common sight in UK gardens, but their numbers have plummeted dramatically in recent years. The population has declined by around two million birds, leading to their placement on the red list of endangered birds in the UK. According to the latest results from the RSPB's Big Garden Birdwatch survey, greenfinches have dropped from being the seventh most recorded species in 1979-the year the survey began-to 18th place in 2025. This stark decline illustrates the serious threat that trichomonosis poses to these birds.
Feeding wild birds is a widespread activity in the UK. It is estimated that over 16 million households put out food regularly, with an average of one bird feeder for every nine birds that visit them. The pet food industry suggests that British households spend approximately £380 million annually on bird food, amounting to more than 150,000 tonnes per year. This quantity of food could theoretically sustain three times the breeding populations of the ten most common garden bird species if they relied solely on it all year round.
In response to these concerns, the RSPB has introduced a new slogan: "feed seasonally, feed safely." Their advice urges people to take a break from feeding birds during the warmer months to reduce the risk of disease spread. They emphasize the importance of hygiene, warning that a single infected bird can turn a busy feeder into a hotspot for trichomonosis transmission.
Despite this, the RSPB does say that small amounts of certain foods-such as mealworms, fat balls, and suet-can be offered year-round, but only enough to last a day or two. They recommend cleaning feeders thoroughly at least once a week and, where possible, moving feeders to different locations after each cleaning. This helps prevent the buildup of contaminated debris below the feeders, further reducing disease risks.
The charity also highlights the importance of clean water. Bird baths or water sources should only be provided if the water can be changed daily, and only fresh tap water should be used. Bird baths should also be cleaned weekly to prevent contamination. Research cited by the RSPB indicates that disease transmission risks are higher on flat feeding surfaces where contamination can accumulate. Consequently, since early 2023, the RSPB has stopped selling flat feeders-such as traditional bird tables-and advised against their use, marking what they call a "fond farewell" to these classic feeding setups.
The new guidance has generated mixed reactions among bird enthusiasts. Many people who enjoy watching birds visit their feeders are concerned about reducing feeding during the spring and summer months. For example, Helen Rowe from the Isle of Dogs in London shared with BBC Your Voice that she regularly feeds sparrows and enjoys watching them from her window. Despite this enjoyment, she said she plans to stop feeding during the warmer months to avoid unintentionally spreading disease, explaining, "I want to support the birds-I don't want to do anything that's going to spread disease."
Others have questioned whether a uniform feeding ban across the UK makes sense, given the varying availability of natural food sources. Dick Woods, who runs a company producing easy-to-clean bird feeders and has campaigned to reduce disease spread, pointed out that "every garden is different." He noted that in some areas, natural food is abundant and birds rarely use feeders, while in others, feeders are a critical food source.
The RSPB acknowledges these regional differences but maintains that a single, clear message is more likely to be effective in changing public behavior. Martin Fowlie of the RSPB stated, "We are well aware that things won't change overnight and that behavior change will take years, if not decades. We have therefore sought to keep our advice as simple as possible to make it easier for people to follow."
The bird food industry has expressed concerns about the new guidance, calling it "a significant change to long-established advice." UK Pet Food, a trade body representing the sector, warned that the changes could confuse the millions of people who regularly feed birds. Michael Bellingham, chief executive of UK Pet Food, said, "The evidence informing these changes is still evolving, and much of the research underpinning this has not yet been published or widely scrutinized."
In response, the RSPB has emphasized that its new guidance was developed in collaboration with scientists from the British Trust for Ornithology and the Institute of Zoology. The charity describes its review of the evidence as "thorough and robust" and plans to publish the full report online. While recognizing the challenges this change poses for the bird food industry, the RSPB insists that "we cannot continue as usual."
Critics have questioned why the RSPB did not update its advice sooner, given that the risks associated with bird feeding have been known for over 15 years. Some have also pointed out a perceived conflict of interest because the RSPB sells bird feeders and bird food, including products bearing its logo, through its shops and online store. The charity responds that it has carefully balanced the growing scientific evidence on disease transmission against the benefits that feeding birds provides. Feeding garden birds, the RSPB says, can improve wellbeing and help people feel more connected to nature.
The charity admits that updating its guidance has taken time due to the complex process of gathering and analyzing scientific data. As part of its new stance, the RSPB also plans to stop selling bird feeders and bird food during the warmer months.
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In summary, while feeding garden birds remains a cherished activity for many, the RSPB's new advice aims to protect vulnerable bird populations from the spread of trichomonosis by encouraging seasonal feeding breaks and improved hygiene practices. The change represents a significant shift in longstanding feeding habits and has sparked debate within the birdwatching community and industry, but it highlights the need to prioritize bird health alongside human enjoyment.