UK Garden Bird Numbers Hit Historic Low — What’s Causing It And What You Can Do

I have looked at the results of the RSPB’s Big Garden Birdwatch every year for longer than I can comfortably admit, and most years bring some shuffling around in the rankings without anything that stops me in my tracks. This year was different. Over half a million people across the UK took part, counting more than nine million birds across over eighty species — and what they found, when you look past the headline that the House Sparrow held onto first place again, is a set of declines in several once-familiar species that the RSPB itself is now describing in genuinely concerned terms.

This is not a doom-and-gloom piece for its own sake. There are specific, identifiable causes behind much of what is happening, and there are specific, practical things every one of us with a garden, a balcony, or even just a window box can do about it. But I think it is worth being honest about the scale of what the data is showing before getting to the solutions.

What This Year’s Count Actually Found

The Big Garden Birdwatch is the world’s largest garden wildlife survey, running every January since 1979, when it began as a simple postal request to viewers of the children’s programme Blue Peter. Nearly five decades on, it has become the single most reliable snapshot we have of how the UK’s most familiar garden birds are actually faring, year on year.

The House Sparrow held the top spot for the twenty-third consecutive year, with Blue Tit remaining at number two and Starling moving up to third place. Woodpigeon and Blackbird rounded out the top five most recorded species in UK gardens this year.

But the headline rankings mask what is happening underneath them. House Sparrow numbers, despite still topping the chart, have fallen by around sixty per cent since the very first Birdwatch in 1979 — and this year’s average count was the lowest recorded since 1998. Starling numbers, once regularly the most commonly recorded species before the year 2000, have declined by somewhere between eighty-two and eighty-five per cent over the lifetime of the survey, a fall the RSPB’s own chief executive described plainly as a reason for concern. The Song Thrush has seen a roughly eighty-five per cent decline since the survey began.

And then there is the Greenfinch, which sits at eighteenth place on this year’s list and has seen a sixty-seven per cent decline in average numbers recorded since the Birdwatch began — a fall significant enough, and ongoing enough, that Greenfinches are now formally on the UK Red List of birds of highest conservation concern.

Disease — The Specific, Identifiable Cause Behind the Greenfinch Collapse

This is the part of the story I think is most important to get right, because unlike some of the broader pressures on UK birds, the cause of the Greenfinch and Chaffinch declines specifically is well understood and directly actionable by anyone with a garden feeder.

There is strong evidence that the primary cause of these particular losses is a disease called trichomonosis, which spreads more easily when birds gather closely around feeders — particularly during the summer and autumn months. The RSPB’s own scientists estimate this disease has contributed to the loss of well over two million individual birds, concentrated heavily in finches that feed at close quarters with one another at garden feeding stations.

What has become clear more recently is that Chaffinches are affected too, not just Greenfinches — meaning the disease risk extends across a wider range of familiar finch species than was understood when trichomonosis first emerged as a serious problem in the mid-2000s.

The reason I think this matters so much for an ordinary garden owner is that, unlike habitat loss or climate change, this is a cause where an individual household’s actions make a direct, measurable difference. Feeding station hygiene is not a minor footnote here — it is the single most significant, controllable lever available to any of us in addressing one of the steepest declines currently showing up in the data.

The Wider Pressures — Why It Is Not Only About Feeders

Disease at feeding stations explains a great deal of what has happened to finches specifically, but it does not explain the whole picture. The House Sparrow and Starling declines, in particular, have causes that go well beyond anything happening in an individual back garden.

According to government and RSPB analysis, the broader decline in UK wild bird populations has been driven by a combination of habitat loss, climate change, pesticide use, and in some years, avian influenza outbreaks affecting wild bird populations. For House Sparrows specifically, loss of nesting sites in modern housing, reduced insect availability for chicks, and changes in urban and suburban green space have all been identified as contributing factors over the long decline since the species was first added to the UK Red List back in 2002.

For Starlings, the RSPB has been notably honest that there is not yet enough evidence to confirm precisely what is driving the decline, despite the scale of it being unmistakable — the breeding population fell by around eighty-two per cent between 1970 and 2022 according to the most recent analysis. That is a useful reminder that not every decline in this data has a single, clean, fixable cause in the way the Greenfinch trichomonosis story does. Some of what we are seeing reflects deeper structural changes to the British landscape that no amount of individual garden management alone can fully reverse.

The most recent State of Nature report found that forty-three per cent of UK bird species are now at risk of decline or extinction — a figure that places this year’s Birdwatch results firmly within a much longer, broader pattern of loss across the last half-century, rather than something that has appeared suddenly or unexpectedly.

What Every Garden Owner Can Actually Do

Given everything above, here is the practical version — the specific actions the RSPB itself, alongside the wider conservation community, is now recommending.

Adopt the updated feeder hygiene guidance. Clean feeders and bird baths weekly, removing old food before it accumulates, and consider retiring flat-surfaced feeders like traditional bird tables in favour of designs that do not allow food and droppings to collect together. This directly addresses the trichomonosis risk behind the Greenfinch and Chaffinch declines specifically.

Let part of your garden grow wild. Letting a patch of lawn grow long through spring and summer, allowing clover, dandelion, and other wildflowers to establish, supports the pollinators and invertebrates that birds — particularly those feeding chicks — depend on. This is one of the simplest and least expensive changes any garden owner can make, and the RSPB has been explicit that it directly supports bird foraging.

Put up nest boxes with appropriately sized entrance holes. The RSPB specifically recommends boxes with an entrance hole of around 1.7 inches for many of the smaller garden species under pressure, positioned correctly and installed well before the breeding season begins.

Avoid pesticides where you reasonably can. Garden chemical use reduces the insect populations that many garden birds, and particularly their chicks, rely on for food during the breeding season.

Take part in the count itself. Whatever else changes in your own garden, simply taking part in next year’s Big Garden Birdwatch — or any of the other citizen science bird surveys running throughout the year — contributes directly to the evidence base that conservation organisations use to understand what is actually happening and where to focus limited resources.

What I Tell People at the Counter

When this year’s results came out, I had more than one customer come in slightly deflated by the headline figures — the idea that a bird as familiar as the Starling has fallen by over four-fifths since the late seventies is a genuinely sobering thing to read, especially for anyone old enough to remember when starling murmurations and noisy starling-filled gardens were simply unremarkable.

What I try to point out is that this data exists, in this much detail, precisely because hundreds of thousands of ordinary people took an hour out of one weekend in January to count what was actually in front of them. That is not a small thing. It is the foundation of every piece of conservation guidance that follows from it, including the specific, practical changes to feeder hygiene that are now being recommended with real confidence because the underlying disease mechanism has been properly understood.

The honest message I want to leave anyone with is this: the picture is genuinely concerning in places, and pretending otherwise would not be doing right by the evidence. But several of the most significant pressures identified — feeding station disease in particular — are ones where ordinary individual action, applied consistently across enough gardens, makes a real and measurable difference. That is worth doing, regardless of how large the headline numbers feel.

Come in if you want advice on feeders, nest boxes, or anything else to help support garden birds. We are at Manor Garden Centre, Cheney Manor Industrial Estate, Swindon, SN2 2QJ — open every day. Or call us on 01793 512400.

Written by Neil — Neil has owned and run Paradise Pets Swindon since 1988. He has kept, bred, and sold cage and aviary birds for over 35 years, and has followed the RSPB’s Big Garden Birdwatch results closely across that entire period. Visit us at Manor Garden Centre, Cheney Manor, Swindon — or call 01793 512400.