Two blackbirds fighting | The RSPB

Big Garden Birdwatch: the bigger picture

Thanks to the hundreds of thousands of people like you who take part in Big Garden Birdwatch, we now have over four decades of data. But what does it tell us and why does it matter?

World's largest wildlife survey

This year marks the 42nd year of Big Garden Birdwatch and it is now the world’s largest garden wildlife survey.

In 2020, nearly half a million people took part, counting almost eight million birds. The Birdwatch is a truly phenomenal collective effort and it is thanks to the hundreds of thousands of people like you taking part that we have over four decades of data. This gives a fascinating and unique insight into our garden birds and how they are faring right across the UK.

Good news for goldfinches...

Goldfinch numbers in gardens increased by 50% over the last decade.

These pretty finches entered the top 10 for the first time in 2008 and in 2020 came in at number six. Great tits have also been moving up the table. Now at number seven, they are up 72% since 1979. So, what’s going on? Both these birds will take advantage of the food we put out for them. As many of you putting out bird food will know, goldfinches in particular will flock to feeders filled with sunflower hearts or nyjer seeds.

...and great tits

Great tit perched on a branch | The RSPB

Great tits too will take advantage of bird feeders and benefit from efforts we make to help wildlife, such as putting up nest boxes. These actions to help garden birds certainly help and it could be that our feeding the birds is contributing to their success. The recent pattern of milder winters may also have helped as more birds are able to survive through the winter.

A sad song for thrushes and greenfinches

Big Garden Birdwatch was one of the first surveys to alert the RSPB to the decline in the number of song thrushes in gardens.

Since 1979 song thrush sightings have dropped by 81%. First ranked at number seven, in 2020 they came in at number 20. The number of greenfinches recorded has also dropped by 65%, from number eight in 1979 to number 18 in 2020. Although greenfinch populations declined in the late 1970s and early 1980s, the 1990s saw a drastic increase. The recent drop has been linked to trichomonosis, a parasite-induced disease which prevents the birds from feeding properly.

Trouble at the top

House Sparrow perched on a bush | The RSPB
Another bird that has shown a marked decline is the house sparrow.

While these cheeky chappies may have ranked number one in the 2020 Birdwatch, a closer look at Big Garden Birdwatch data shows that numbers seen in the Birdwatch have dropped dramatically since the Birdwatch began, down 53% since 1979. In fact, the drop in their overall population in the UK, means that they are now on the red list, the highest level of conservation concern.

Understanding the decline

Exactly what is behind the decline is not clear, but together with other scientists, the RSPB is investigating what’s going on.

One project in Leicester found that sparrow chicks were suffering due to a lack of invertebrates to eat, while a team from the ZSL Institute of Zoology, in collaboration with the RSPB, found that 74% of London’s house sparrows carry avian malaria, possibly influenced by our warming climate. There are some signs for optimism though. Big Garden Birdwatch 2020 figures suggested that sparrow sightings have grown by 10% in the last 10 years.

Road to recovery

Girl in green jacket hangs a homemade bird feeder in her garden, Bristol
The reasons behind the declines in garden bird sightings are complex and continue to be investigated.

Fewer green spaces, pollution and a changing climate are just some of the challenges faced by many birds. By better understanding what is happening we are better equipped to find solutions. We also know that many garden birds will benefit from any extra help that we give them. Looking back over the last 40 years, one thing the Big Garden Birdwatch has revealed is that for some birds, our gardens are increasingly seen as places to find food, water and shelter during the winter.

Take part

We know that many of you who enjoy doing Big Garden Birdwatch also give nature a helping hand through actions such as feeding the birds, putting up nest boxes and by wildlife-friendly gardening. And it’s actions like these that really can make all the difference. So take part in the Birdwatch with pride!