The Mistle thrush is disappearing from UK gardens at a rate that suggests the species is "in need of help," according to the Royal Society for the Protection of Birds.
Results from the RSPB's previous annual Big Garden Birdwatch surveys have shown that sightings of the pale, black-spotted bird have fallen by more than 50% over the last 10 years – worrying news since the species is already on the amber-list of conservation concern.
Wildlife experts are not sure why the bird's numbers are falling, but have said its decline resembles that of the closely related and currently endangered song thrush.
The RSPB is now urging everyone to get involved in this year’s survey to see if the picture has changed and identify other species that may need attention.
The event, now in its 34th year, is the world's largest wildlife survey and takes place on January 26 and 27.
Since the first survey in 1979, the annual Birdwatch has identified dramatic declines in other UK garden birds: starlings have fallen by 80% and house sparrow numbers have fallen by 66%.
Sarah Houghton, RSPB manager for the Birdwatch said: “The decline of birds like starlings and sparrows over the last 30 years or so have been alarming, but [the] Big Garden Birdwatch has helped us find out more about their numbers and distribution across UK gardens, and that has been the first step in helping to put things right.”
She added: “No matter where people take part, whether at home with the family, with classmates at school or with friends in the beer garden of the local pub, we’re all joining forces to gather vital information about some of our most familiar garden birds.”
Last year across the UK almost 600,000 people - among them 90,000 school pupils and teachers - took part in the Birdwatch, counting more than nine million birds between them.
During its time, the survey has brought not just bad news.
Its results have also shown increased sightings of well-loved bird species like blue tits, great tits and coal tits over the last 30 years.
Goldfinches have also grown more common and have steadily risen into the top 15 garden bird species since 2004.
To join in the world’s largest wildlife survey, simply spend one hour at any time over the Big Garden Birdwatch weekend noting the highest number of each bird species seen in your gardens or local park at any one time, then submit your results to the RSPB .