To reduce disease, we all need to make some urgent but simple changes to how we feed our garden birds.
We all want to help birds and make our gardens or outdoor spaces a place where all wildlife can thrive. But some species, such as Greenfinches, are experiencing serious declines because of disease.
The good news is that we can help reduce the spread of disease by making two simple changes to the way we feed our birds.
Research has shown a worrying decline in some of our much-loved garden birds due to a disease called trichomonosis. This is a highly contagious disease and can spread where birds gather in large numbers such as at bird feeders.
Greenfinches, for example, have dropped by over 65% in the last three decades – and you may have seen this decline yourself. Back when the Big Garden Birdwatch started in 1979 Greenfinches were at number seven in the top ten birds seen. This year they were down to number 18.
We’ve been working with experts to find a solution, and we believe that, together, we can make a difference by feeding birds seasonally and safely.
We can help stop the spread of disease among garden birds by making two simple shifts to how we feed birds. Put simply: Feed seasonally. Feed safely.
During summer and autumn, there’s a higher risk of disease spreading. But it’s also when there are more natural foods available to birds, such as seeds and insects.
Busy bird feeders can become hotspots for disease. To help keep birds healthy, it’s vital to keep things clean – which is why we’ve strengthened our existing hygiene guidance. We recommend you:
Stopping the spread of disease is a challenge we can’t tackle alone. By taking these simple steps to feed seasonally and safely, we can all help protect the future of our birds.
Sign up to our free fortnightly newsletter, Notes on Nature, to be reminded when to switch your bird food throughout the seasons.
We need more research to find ways to reduce the risk of disease spreading at bird feeders. Some studies are already under way, but we don’t yet know if or when they’ll lead to effective solutions. It’s also important to remember that this advice may evolve as new evidence comes in. But the science shows we need to take action. We believe changing how we feed birds now will help protect them in the longer term. It will take time to see the benefits, so patience is important.
Our experts have put together answers to some of the key questions you may have about this new bird feeding guidance.
You can find more of our recommendations on bird feeding, including on types of food and how to clean your feeders and bird baths, here.
You can find some suggestions on what to plant to help your garden birds throughout the year here.
An evidence review into the pros and cons of feeding garden birds found strong evidence that supplementary feeding promotes the spread of diseases in gardens, including the trichomonosis parasite.
Across the UK, trichomonosis has caused serious declines in Greenfinch and Chaffinch populations and may now be causing a rapid decline amongst Bullfinches. The scientific evidence shows that the risk of trichomonosis outbreaks is highest in summer and autumn.
Our Conservation Scientists have worked with other expert partners to find a solution. We now recommend that you pause feeding garden birds seeds and peanuts between 1 May and 31 October. You can continue to offer small amounts of mealworms, fatballs or suet. During spring and summer, dried mealworms can be soaked in water to make them easier for nestlings to eat.
We are currently seeing huge declines in the UK’s Greenfinch and Chaffinch populations, and we may also be seeing a rapid decline in Bullfinches, caused by the disease trichomonosis. Finch species prefer to eat seeds, but when seeds aren’t available, they will divert to peanuts. As finches rarely eat fatballs, suet and mealworms, we consider these foods are low risk when it comes to the spread of trichomonosis.
To further reduce the risk of disease, we also recommend that you: feed only small amounts; don’t use bird feeders with flat surfaces; keep your feeders clean; and only put out water if you can change it every day.
The evidence review found that it’s often beneficial to feed birds during winter, especially during cold weather when natural food can be in short supply. Birds can also benefit from feeding between March and April. This is sometimes called the ‘hungry gap’ as there are often fewer natural foods available for seed-eating birds such as finches at this time of year.
Furthermore, although trichomonosis occurs all year round, the parasite is killed by cold weather, and the likelihood of disease outbreaks is lower during winter.
We have carefully balanced the benefits of feeding against the risks of disease, and we believe that we can continue to feed our garden birds, as long as we feed the right types of food at the right time of year. By following our guidance to feed seasonally and feed safely, we can all help protect the future of our birds.
We know that the trichomonosis parasite can survive in water and this may be one way the disease is spread in gardens. To minimise the risks, we recommend that you only put water out for birds if you’re able to change it every day, using tap water, and if there is no local pond available.
A pond is often the best source of water for birds – ponds are likely to have a lower risk of trichomonosis than bird baths.
You can find more information about best hygiene practices and how to safely provide water here.
Yes. Our evidence review found that bird tables and other flat feeders pose the greatest risk of disease transmission.
Birds that are sick with trichomonosis often perch on flat surfaces where they attempt to feed. The disease makes swallowing food difficult, so they often regurgitate contaminated food back on to the flat surface where it is then available for healthy birds to pick up. Even daily feeder cleaning will not prevent the consumption by healthy birds of previously regurgitated food. That’s why we advise that no flat-surface feeders, including bird tables and window feeders, are used to feed birds.
We believe there is enough natural food available for garden birds between 1 May and 31 October. Natural food plants are at their peak during this time, and we expect that birds will adapt to the removal of seed and peanut feeders in gardens.
By following our guidance to feed seasonally and feed safely, we can help reduce the spread of disease. We will also be monitoring how garden birds respond and may refine our advice in the unlikely event that there are problems with food shortages.
We know people enjoy feeding birds, and many of our supporters tell us how much joy it brings them and how beneficial it is for their wellbeing.
We also know that people are keen to help their garden birds. This year, well over half a million people (650,279) took part in the RSPB’s Big Garden Birdwatch to help us understand how garden birds are faring.
We hope that this nation of bird-lovers will be keen to help garden birds by following our advice to feed seasonally and feed safely. After all, for most people who feed birds, an important motivation is to help birds survive.
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