The fate of the house sparrow is an example of the value of citizen science, says James Robinson, Eastern regional director of the RSPB.

House sparrows are gregarious birds and have always been closely associated with our homes (hence the name). As we have colonised and expanded our towns and cities, house sparrows have joined us, exploiting our rubbish, making the most of what we have to offer.

'Exploit', however, is an unfair term and nimble adaptation is perhaps more fitting. Over the last century, as our agricultural practices have changed – particularly loss of winter stubble and improved hygiene measures around grain stores – house sparrows sometimes no longer have a choice in whether they'd prefer to inhabit a country or town residence; these avian opportunists have found new homes in our towns and cities.

Quarrels of house sparrows squabbling over scraps on the bird table, and nesting birds flitting from buddleia bushes to the eaves of our homes carrying nest materials are common sights. Incessant chirruping and chirping is a background soundtrack to urban life in many places.

On the surface it looks like an opportunist personality is paying off: house sparrows topped the RSPB Big Garden Birdwatch charts in 2017, with an average of four birds being seen per garden here in the east. If we looked at last year's numbers in isolation, it would be easy to assume that house sparrows are doing just fine.

Luckily though, here at the RSPB, we have been monitoring house sparrow numbers since 1979 when the first Big Garden Birdwatch took place. Over decades of data-gathering, scientists and conservationists have identified that house sparrows are declining at a worrying rate. From 1979 to 2017, numbers have declined by 57%. Not just in the countryside, but in cities and towns too. Even our greatest avian entrepreneurs can't keep up with our changing 21st-century lives.

Possible reasons for this decline include a reduction in the availability of their preferred foods, increased levels of pollution, loss of suitable nesting sites, increased prevalence of disease, and increased levels of predation. However, the exact causes of these rapid declines remain unclear.

Since identifying the decline, the RSPB and others have undertaken scientific research to learn more about struggles this species faces in urban and suburban centres and hopefully turn their fortunes around.

Yet, without the Big Garden Birdwatch, and other citizen science surveys, we would not have known this research was needed. We could have been blind to a seemingly abundant bird's suffering.

Citizen science is a truly remarkable tool. National surveys like the Big Garden Birdwatch have a place in society. A place in bringing people together, enthusing people about their garden birds, offering people moments of mindfulness, and enabling everyone to do their bit for nature.

We need Big Garden Birdwatch and we need people like you to take part. You will be contributing to vital research at a time when funding for nature conservation becomes ever-tighter, you will be helping to give nature a home. Last year over 76,000 people took part in the east, and close to half-a-million took part nationally. That's data from nearly half-a-million gardens! Imagine this year if we had even more…

Big Garden Birdwatch is happening over January 27, 28 and 29. To sign up for free visit rspb.org.uk/birdwatch and you will receive an RSPB shop voucher, a bird identification chart, and advice on attracting more wildlife to your garden.