Should We Stop Feeding Garden Birds? Adrian Thomas from the RSPB Explains

Sarah: I know you have a day job with the RSPB, but wildlife gardening is clearly a passion of yours. You’ll be the perfect guest, as everybody who listens to the podcast loves talking about wildlife.

I’ve looked through the recommendations and research, and I’ve got some questions for you. It’s going to be very conversational, so shall we crack on?

Adrian: Yes, absolutely. Just before we start, I should say that when it comes to trichomonosis and the disease-related issues, I’m not the expert. I know a fair amount about it, but I’ve been put forward as a gardener rather than a disease specialist.

Sarah: That’s fine. If I ask you anything you don’t want to answer, just say so. We can edit things out, so feel free to tell me if you’d rather move on.

Adrian: Lovely. How expansive would you like me to be with my answers? Do you prefer short and sweet?

Sarah: Just play it by ear. Be as expansive as you like. It might mean I ask fewer questions, but if we get onto something you’re particularly interested in, go for it. It’s always better for me to have somebody who’s chatty, because it means I can do much less work and just listen and enjoy it!

Adrian: Excellent.

Sarah: I think we’re scheduled to go out in October, aren’t we? I’ll check with Louise, but I know she wanted it to go out at a particular time. It won’t be next week, but it’ll be imminent.

Adrian: I think it would be good to publish it just before the switch back to winter bird feeding on 1 November, or whenever is convenient for you.

Sarah: Perfect. That’ll be the end-of-October episode, then. Just bear in mind that some of the things I might mention, such as seeing goldfinches, won’t necessarily be happening at the time the episode goes out.

So, first question: what do you do, and how did you become interested in birds and wildlife gardening?

Adrian’s work with the RSPB

Adrian: I effectively have two jobs with the RSPB.

My day job is fantastic. I’m a project manager, which covers all sorts of things. I can set up a new nature reserve, run a campaign, and I once even helped the RSPB get into the pop charts. Number 18, I’ll have you know!

My love of nature has been with me ever since I was a small child. As far back as I can remember, the presents I wanted for birthdays and Christmas were things like a little pair of binoculars and a bird book. I wanted to be out in the garden.

My second role with the RSPB is entirely voluntary, but it’s been a long-standing one. I’ve been something of the face of wildlife-friendly gardening for the RSPB for well over 20 years, and I’ve written the RSPB book about it.

I’d like to think of myself as a very active gardener. I constantly have mud under my fingernails, and I’m out there every day. The first thing I do in the morning, after breakfast, is walk around the garden. It gets me ready for the day. I see how the garden is faring and spot what wildlife is visiting.

Those things are what keep me happy.

Sarah: I love it. That sounds like the perfect job!

We’re here to talk about some research the RSPB has carried out and published. I think I may be a little confused, because we all saw the headlines telling us to stop feeding birds. We know what the media is like when it comes to dramatic headlines, but your research seems to have produced a much more nuanced message.

Can you explain the RSPB’s current position on feeding garden birds?

Should we stop feeding garden birds?

Adrian: Absolutely. Nuance is a great word for it.

If you go back to the 1980s and 1990s, the advice was to feed birds all year round. That was the blanket recommendation: put food out and keep it available throughout the year.

We know that feeding can benefit many birds. It can help them survive the winter, but there’s also a hungry gap in spring. We might feel that temperatures are warming up, but there are still very few insects around, and plants aren’t necessarily producing seeds. Early spring can be a difficult time for birds, and supplementary feeding can help.

However, concerns began to emerge that feeding birds might also have detrimental effects.

The RSPB, alongside a range of partner organisations, carried out a thorough review of the research into garden bird feeding and its impacts.

In particular, we were concerned about the devastating declines in greenfinches and chaffinches. These were once very common birds in gardens across the country, but their population declines have been startling.

Between 2014 and 2024, greenfinch numbers declined by 42% across the UK. When you’re looking at a population of around one and a half million birds at the start of that period, that’s a loss of several hundred thousand greenfinches.

The decline in chaffinches started a little later, but you’re talking about a bird population that began at around 10 million. Over the same ten-year period, we’ve seen a decline of 38%. That’s millions of chaffinches lost across the country.

We wanted to understand what was happening, because there were indications that something associated with bird feeding might be contributing to the problem.

The review concluded that a disease called trichomonosis was responsible for much of the decline. It’s caused by a tiny parasite, rather than a bacterium, which lodges in a bird’s throat and causes lesions. These can make it difficult for birds to swallow food and breathe properly.

The parasite is transmitted most easily when birds gather unnaturally in the same place repeatedly, such as at bird-feeding stations.

The RSPB also carried out field research, looking for the parasite in and around bird baths, feeders and bird tables. This helped establish where the parasite was most likely to be transmitted: particularly at flat feeding stations, such as bird tables, and potentially at feeders too.

We had to weigh all this evidence against the benefits of feeding birds. There are still very good reasons to provide supplementary food, but we now understand that it can have detrimental effects, particularly on greenfinches and chaffinches.

The revised advice is that, because these finches particularly like seeds and peanuts, we should stop feeding those foods between May and the end of October. We can resume feeding them during the winter months, when the parasite is less able to multiply and spread.

It’s a complex message, but the simplest way to put it is: feed seasonally and feed safely.

Don’t feed seeds and peanuts during the summer months, from May through to the end of October. Also, keep feeders clean, avoid bird tables and other flat feeding surfaces, and keep bird baths clean.

Combining seasonal feeding with good hygiene gives us a much better chance of reducing the spread of this parasite.

Sarah: When you say the parasite is killed off in cold weather, I automatically think about how our winters aren’t particularly cold these days. Will the parasite still be reduced if we continue to have very mild winters?

Adrian: Yes. The evidence suggests you don’t need a heavy frost to see it off. Lower winter temperatures make it more difficult for the parasite to multiply and spread.

Winter is still cool, isn’t it? Our plants struggle to grow, and I put on several layers!

We also know that birds need supplementary food more during winter and early spring than they do at other times of the year, when natural food is more readily available.

It’s not a perfect scenario, and we’ve had to choose dates that are a reasonable approximation of when it’s best to feed seeds and peanuts and when it’s best not to.

But we believe that, based on the evidence and the good science underpinning the RSPB’s work, this approach gives us the best chance of retaining the benefits of bird feeding while reducing the negative impacts.

Which birds are affected by trichomonosis?

Sarah: Is it just finches that are affected?

Adrian: This disease has long been known in pigeons and doves, where it’s called canker.

It’s thought that the parasite may have passed from pigeons and doves into finches, adapting to infect smaller birds. This may have happened because of the repeated gathering of large numbers of birds in the same place, day after day, particularly where food isn’t cleaned or refreshed often enough.

That’s why feeding safely matters. It’s about cleaning feeders, avoiding food left on flat surfaces, and moving feeders around so that the same patch of ground isn’t repeatedly exposed to food debris and droppings.

Sarah: If the parasite has moved from pigeons to finches, could it move from finches to other species?

Adrian: That possibility always remains. We’re not seeing definitive evidence of that happening more widely, although we are concerned about declines in bullfinch numbers. We don’t yet have proof that trichomonosis is responsible for those declines.

I think this has shown us that we need to be mindful of the risks associated with supplementary feeding, alongside all the enjoyment it brings.

I love seeing birds coming to my feeders. It gives me a connection with nature, particularly during the winter months, and it enlivens the garden with colour and activity.

But supplementary feeding does come with risks. The more we recognise those risks and practise good hygiene, the better.

We’re very conscious of food hygiene when it comes to ourselves. Applying some of those same principles to how we feed birds seems a sensible conclusion.

Sarah: I’m going to ask you a slightly flippant question. You could argue that if finches are affected, it’s survival of the fittest. Are other species filling the gap as finch numbers decline? Are any other birds benefiting?

Adrian: I don’t think there’s evidence at the moment that other species are stepping into that gap.

I tend to call what we put out supplementary food because natural food, such as insects and naturally produced seeds, should always make up the bulk of a bird’s diet. Supplementary food provides an additional benefit.

Given the scale of the declines, greenfinches have already been placed on the Red List of birds of highest conservation concern. Chaffinch numbers are also falling, and there’s a possibility they could be added to the Red List at a future review.

So many birds are struggling in the wider environment. We have a nature crisis and a climate crisis happening together.

Anything we can do to help the birds in our gardens thrive is worthwhile. As gardeners, we can look at our gardens and feel we’re having a positive effect on wildlife.

There are around 16 million gardens in the UK, each with the potential to do something really beneficial to help tackle the nature crisis.

We should do everything we can to make those gardens as positive for wildlife as possible and take steps to address anything that’s going wrong.

Wildlife gardening in urban and rural areas

Sarah: I think you might be in a bit of a catch-22 as a gardener.

In an urban garden, supplementary feeding might be more important because the natural environment isn’t providing enough food. On the other hand, you might have higher concentrations of birds around a feeder.

Does the research show whether this is more of a problem in rural or urban gardens?

Adrian: I think it’s worth stepping back 30 or 40 years, when gardens were often seen as relatively unimportant for wildlife.

People knew wildlife used them, but it was often characterised as common-and-garden wildlife.

What we’ve learned from research over the last 10 to 15 years is just how important gardens actually are. They’re not a second-rate habitat. They support amazing populations of moths, butterflies, solitary bees and birds.

The Big Garden Birdwatch, which is largely carried out in people’s gardens, gives us a real testament to how important those spaces are.

Of course, not every garden is equally good for wildlife. Some are brilliant, while others offer very little.

The more we can do collectively to make our gardens rich in wildlife, the better it will be for the future of wildlife in the UK.

And the good news is that we can make gardens brilliant for wildlife with some really simple steps.

How should we clean bird feeders?

Sarah: You mentioned cleaning feeders and moving them around. Is there a particular routine people should follow?

Adrian: Yes. I don’t want to make the rules too strict or onerous, but the recommendation is to clean feeders weekly.

Use a weak disinfectant solution, give the feeder a good clean, let it dry, and then refill it.

We also need to retire flat feeding surfaces. Unfortunately, bird tables are no longer recommended because they can be places where the disease is readily transmitted.

Change the water in bird baths daily and clean the baths weekly.

If all of that feels too much, I’d encourage people to concentrate on providing natural food in their gardens rather than taking unnecessary risks with feeders.

But a weekly clean of feeders should be manageable for most people, and it can help protect the birds that benefit from supplementary feeding.

Sarah: I’ve noticed that there are still some flat feeders for sale on the RSPB website. I’m guessing those will be phased out shortly.

Adrian: I’d expect so. We were ahead of the curve with this advice and moved away from flat feeders as a precaution.

Bird tables and flat feeders of all types are no longer recommended.

Feeding birds during the breeding season

Sarah: During spring, birds are feeding their young. My understanding is that many chicks can only be reared on invertebrates.

Does that mean supplementary seeds and peanuts are mainly helping the adults while they’re doing the difficult job of feeding their young?

Adrian: Yes, but the lovely part of this whole story is that we’re only asking people to change their feeding of seeds and peanuts during the summer.

Many people also feed mealworms and fatty products, such as fat balls and suet. These can continue to be offered throughout the year because they’re not foods that greenfinches and chaffinches typically rely on.

That means you can still have bird food out in your garden all year round.

As we sit here, I’ve got fat products out in my garden, and they’re being enjoyed by great spotted woodpeckers, blue tits, long-tailed tits and great tits.

During summer, it’s advisable to put out only small amounts of fat products because they can deteriorate in the heat. Just put out a little at a time and replace it as it’s used.

So this isn’t a blanket ban on feeding birds. It’s about taking care not to feed seeds and peanuts between May and the end of October, while continuing to provide other suitable foods.

Sarah: I think that’s where the confusion arose, because the headlines were saying, “Don’t feed the birds.” People were left thinking they couldn’t do anything right. It’s good to get some clarity.

I also wanted to ask about the garden environment. One of the things I read in the research, which seems like common sense but might not occur to everyone, was that you shouldn’t put feeders under trees because they could be contaminated by droppings from above.

Are there other simple things people can do to avoid problems?

Adrian: Moving feeders around the garden is one of the most useful things.

In the past, I’d always put my feeder in the same place. That’s where it went every time I filled it.

But I’ve now identified three places around the garden. When I refill the feeder, I move it to the second place, then the third.

This mirrors birds’ natural foraging behaviour. In the wild, birds find a concentration of food, use it for a while and then move on to find another source.

They might find a patch of beech mast or a concentration of sunflower seeds, feed there for a few days and then move on.

Many garden birds spend their days moving from garden to garden and place to place in search of food.

If you can move your feeder around, it makes it harder for food debris and droppings to build up in one spot.

For example, if you hang your feeder from a nail on the fence, you could put another nail a few panels further along and move the feeder each time you refill it.

That way, you’re reducing the build-up of potentially contaminated material underneath it, while encouraging something closer to the birds’ natural foraging behaviour.

Sarah: Would moving it a few metres be enough?

Adrian: It would certainly help. I know many people have small gardens, but almost every garden should have two, three or four places where feeders can be moved between.

Do birds become dependent on garden feeders?

Sarah: Can birds become reliant on a particular garden?

Adrian: It’s unlikely.

An interesting piece of research on greenfinches, carried out before the decline, looked at how many birds were actually visiting a garden.

You might only see five greenfinches at any one time, but the research suggested that the total number visiting could be 50 or even 100. Those five birds move on, and another group arrives.

Most birds use a much wider area than a single garden.

That reliance is even less likely if we’ve made our gardens wildlife-friendly, with natural food as well as supplementary food.

Gardens typically contain shrubs, hedges and trees that provide seeds, insects and other natural food.

I watch the blue tits and long-tailed tits moving through my garden. Long-tailed tits might pause at my feeders for 10 or 15 seconds before continuing on their way around the neighbourhood, perhaps stopping at other feeders as they go, but also using hedges and trees.

I wouldn’t worry too much about birds becoming dependent on your feeders. What’s more likely is that you’re seeing a procession of different birds stopping for a snack as they move through the area.

How are British bird populations doing?

Sarah: What are the overall trends for birds in the UK at the moment? Are populations declining across the board?

Adrian: Thankfully, it’s not across the board, but overall, bird populations are struggling.

Some habitats are doing worse than others. Farmland birds, in particular, are struggling, and woodland birds aren’t doing especially well either.

Rarer species can do quite well because of the conservation work that goes into protecting them. But most of the birds we see in gardens aren’t rare species; they’re the more familiar birds that visit our gardens.

Some are doing reasonably well, and climate change has played a part in that for certain species. We’re not seeing as many birds lost over the winter because we no longer have the same frequency of severe frosts, and supplementary feeding may also help.

Great spotted woodpecker numbers are increasing significantly. Blackcaps, which used to be primarily summer-visiting warblers, have increasing breeding populations. They’ve also become established as winter visitors in the UK and are particularly attracted to fat feeders in gardens.

Interestingly, blackcaps that visit gardens in winter have been found to have longer beaks than those that don’t. A longer beak helps them reach food in feeders more easily. We’re seeing evolution happening in our own time.

However, alongside those species that are doing well, others are declining.

House sparrows have undergone a major long-term decline and are on the Red List. Starling numbers have fallen dramatically, and they are also Red Listed.

We’re beginning to see worrying declines in collared doves, and we’re concerned about some summer visitors, including swifts and house martins.

Sadly, there are more worrying stories than good-news stories overall. It’s encouraging that some species are doing well, but we need to understand why others are struggling.

The wider countryside is becoming less suitable for so many bird species, which makes our gardens even more important than they once were.

Creating a wildlife-friendly garden for birds

Sarah: It’s such a moving target. There’s so much going on, and even with the best will in the world, things can be unpredictable.

The wider countryside worries me, too. I see a lot of practices that destroy habitats, so gardens are increasingly becoming refuges for wildlife.

If you had a few general pointers for people who want a wildlife garden, what would you say is particularly beneficial for birds?

Adrian: I love the fact that my key message to gardeners is: plants, plants and more plants!

You’ve got every permission to grow as much as you want in your garden.

Part of it is about structure. Trees and shrubs provide song perches and nesting places, but they also support insects, which are important for adult birds and particularly for their young.

It’s vital that we grow plants without using insecticides. I know that’s something very close to your heart, Sarah. We mustn’t remove important layers of the food chain by using insecticides and pesticides in our gardens.

Water is also really important for birds. One interesting aspect of the trichomonosis research is that bird baths can be a significant transmission point, whereas a pond, even a small one, is much less likely to be one because of the greater volume of water.

A pond with a little beach area where birds can drink and bathe is fantastic. It also produces insect life and provides many other benefits for wildlife.

I also think dead plant material is really important. Plants are great for wildlife when they’re alive, but they still have value when they die.

That might mean stick piles, log piles, compost heaps or piles of leaves that can be turned into leaf mould.

Look at blackbirds and song thrushes in winter. If you’ve raked leaves off the lawn, try spreading them underneath trees and shrubs. You’ll see blackbirds flicking through them to find food.

All these things are valuable.

We often talk about putting up nest boxes, and they can be very useful for species such as blue tits and great tits, as well as swifts and house martins under the eaves.

But many of our garden birds don’t nest in boxes. They need dense cover, such as evergreen hedges, a thick hawthorn hedge or a holly tree. Evergreens are particularly useful early in the season when birds are nesting.

I’ve been experimenting in my own garden with an idea for people who don’t have room for a hedge in the traditional sense: a linear row of small trees.

Could you plant a little wedge of hedge instead? Just a triangle of dense planting in one corner of the garden could provide useful nesting cover.

I remember being on a radio interview when someone asked about magpies predating a song thrush nest they’d been watching. Understandably, they were upset.

As we talked it through, it became clear that the song thrushes had very few places where they could nest. They’d chosen an unsuitable location where the nest was visible to everything around it. No wonder the magpies had found it.

Thinking about how to maximise the number of potential nesting sites for robins, wrens, dunnocks and blackbirds is really important.

For me, it all comes down to filling the garden with a diversity of plants and structures.

Have a pond, some longer grass and some shorter grass. Shorter grass is useful for starlings and blackbirds.

It’s all about diversity and green space. A garden that doesn’t use insecticides and provides a rich habitat is a brilliant place for wildlife. Birds will recognise that.

They have a wonderful eye for spotting a rich habitat, and isn’t it wonderful that we can create one in so many gardens?

Do birds pollinate plants?

Sarah: It is indeed. I’ve got one last question, which might be a bit of a curveball.

Some new research has come out suggesting that birds actually pollinate plants. Have you seen that?

Adrian: I have, yes. It’s really fascinating.

I’m used to seeing blue tits visiting my winter-flowering cherry, particularly because they’re trying to steal the nectar. I’ve also seen blue tits visiting kniphofia and emerging with orange foreheads where they’ve picked up pollen.

This recent research has looked at whether birds pollinate native plants, and the findings suggest that they probably do.

If you experimentally exclude birds from plants, their production of seeds and berries can be lower than when birds are allowed access.

It’s a fabulous piece of research, and it’s something that’s been hiding in plain sight.

We talk so much about pollinating insects, but it’s fascinating to discover that many birds are doing the same thing, even if inadvertently.

Plants may not have evolved specifically to encourage this relationship, as they have with insects, but the connection is there.

We tend to think of pollination as a relationship between plants and insects, so it’s great to discover that birds are contributing too.

Well done, birds!

Adrian’s experimental wildlife garden

Sarah: I love that. Thank you for answering that question. I know you probably weren’t expecting it!

Adrian, I think that’s fantastic. Are you happy to leave it there?

Adrian: I could keep talking for ages! I could tell you all about my bird-seed border that I planted this year to provide an alternative food source now that the feeding advice has changed.

It’s been fabulous talking to you. Thanks very much, Sarah. Let’s get that message out.

Sarah: You’ll just have to come back on again, perhaps next year when people are thinking about their summer borders.

Adrian: I’d love to. I do lots of little experiments in my garden, because whenever I talk about a subject, I want to have tried it myself.

I have ponds of all different shapes and sizes and experimental borders, all to see what works and what doesn’t.

That includes finding out whether things look good, too! I still want my garden to look good and feel good.

It’s all great fun.

Sarah: I love that. You’re doing great work, Adrian. Thank you.

Adrian: My pleasure. Thanks so much.