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The Big Garden Birdwatch

Blue tit

Every year, at the end of January, the RSPB runs its Big Garden Birdwatch. Approximately half a million people take part in this popular citizen science event. Running for over 40 years, it provides conservationists with an invaluable snapshot of how our birds are faring. It is extremely easy to take part, as well. In this post we’ll look at why it is so useful to researchers, what past surveys have revealed and how to join in.

Why Survey Garden Birds?

Many people might take their garden birds for granted. After all, it can be easy to become complacent about the state of robin, blackbird or house sparrow populations when we see them every day. Their seeming ubiquity, though, could mask long-term issues, for nature in general or for particular species. Regular surveys, therefore, can help to reveal problems that we might not otherwise pick up on. And by carrying out surveys each year at the same time, scientists can make worthwhile comparisons. They can clearly see which species are declining, increasing or holding steady. In addition, the surveys show whether any population changes are short-term blips or something affecting a species over a longer period. Plus, they are an increasingly important tool for monitoring how our birds are coping with the climate crisis.

The Big Garden Birdwatch has helped to reveal worrying starling declines

Gardens are becoming increasingly important for our wildlife as other habitats become more and more depleted by factors such as development, agriculture and climate change. Indeed, the survey’s results have shown that there are now species frequently using gardens that would once have done so rarely, including long-tailed tits and siskins. So, surveying our garden birds helps to shine a light on the health of nature more generally. You might be wondering why the RSPB chose a winter date for their counts. At this time of year, birds rely on gardens more than ever as food becomes scarcer elsewhere. This means it is much easier to see many of our commoner species and more people can contribute their sightings.

Forty Years of Changes

The first Big Garden Birdwatch was in 1979 and run for children in conjunction with Blue Peter. It was originally supposed to be a one-off but was so successful, it became a regular event. Over 40 years of data has now been collected and this has revealed some worrying declines in our bird populations. House sparrows and starlings, for instance, are two of our commonest birds. House sparrows have topped the survey list for 19 years running. Despite this, though, results show that sparrows have declined in our gardens by 56% since 1979. Even more worryingly, the starling decline is 80%. This again highlights how important long-term surveys like this are. Without them, we might not notice when still numerous species’ populations are collapsing until it is too late.

House sparrows
House sparrows are Red Listed in the UK due to big population declines

The event has also revealed problems for some of our other species. For example, greenfinches were once a fairly common visitor to garden bird feeders. However, years of surveys have revealed a worrying decline. Scientists have discovered this is largely down to a disease called trichomonosis. This can be spread at feeding stations, so it highlights just how important it is to regularly clean your bird feeders. Song thrushes are another bird that was once common in our gardens. In the 1979 survey it was in the top 10 of commonest birds seen. By 2019, it had slipped down to 20th. It isn’t all bad news, however. Great tits are up by 68% in gardens since 1979.

Greenfinches have been hit hard by trichomonosis

Evolution in Action

The count has also contributed to our understanding of some fascinating evolutionary changes. When the survey began, blackcaps would have been an extremely unlikely winter garden visitor. Now, however, many participants are logging them on their Big Garden Birdwatch counts. Purple Plover has even had winter blackcaps as far north as Inverness. A combination of garden records and tracking shows that many blackcaps from mainland Europe are now heading to our shores instead of their usual wintering grounds of southern Europe and Africa. Incredibly, some of them are even flying north from Spain.

Blackcap male
A blackcap in the snow would have been an unimaginable sight a few decades ago

Warmer winter temperatures and our love of feeding birds are almost certainly a factor. Most blackcaps migrating here by mistake due to faulty genetics would once have died due to the cold and lack of food. Many now survive to breed the following year. This means an increasing number of blackcaps pass on the faulty migration gene to future generations. They in turn then head to the UK for the winter too. Although of less value scientifically, there is always the chance, too, that a real rarity will show up in your garden. In 2014, for instance, two children taking part in County Durham recorded what turned out to be a lost myrtle warbler from North America.

How to Take Part

Taking part in the Big Garden Birdwatch is extremely easy. Once you have signed up on the website, you just need to spend one hour between the 27th and 29th of January watching your garden or balcony. If you don’t have a garden, you can choose a local park instead. During the hour, count every bird that you see actually land on the ground or a tree. Don’t include birds that just flyover. Once you’ve completed your count, log them online before 19th February. There is a postal option, as well. You can choose any time of day and don’t worry if the weather is bad. The volume of submissions even out any low counts caused by weather or timing. It is important to log your results even if you see nothing over the hour.

Song thrush
Song thrushes are a much less common garden visitor than in 1979

There is a wealth of information available to help with the event. This includes guides to what you can expect to see and information on how to attract birds to your garden. Over the weekend there will be lots of events online including interviews, live streams and a chance to ask questions. The results of the 2022 count can be found here, and there are links to regional results as well. In addition, the Big Schools’ Birdwatch runs until 20th February and gives schools a chance to get involved counting the birds around their grounds.

By spending just one hour over the Birdwatch weekend watching your garden, you can make a real contribution to conservation. Happy counting!