Train stations, public buildings, sports venues and Co-op stores across the UK will come alive with birdsong on Thursday.
The RSPB is bringing the sound of birds singing to an estimated five million people across the country to raise awareness of falls in the country's bird populations and what the UK stands to lose if the declines continue.
It comes as polling for the charity reveals high levels of support among the British public for the Government to prioritise tackling climate change and environmental problems.
Among 18 to 44-year-olds, climate change and the environment came out top in terms of what people would like to see the Government address as their long-term legacy.
And among UK adults as a whole, climate change and the environment were in the top three, with 38% naming it as a priority, beating Britain's future relationship with the EU (36%) and coming in behind only health on 44%.
Almost three-fifths of people believe nature in the UK is in crisis or not doing well, the poll of more than 4,000 people by YouGov found.
After scoring a surprise top 20 music hit with a track of birdsong Let Nature Sing in the summer, the RSPB has teamed up with partners to bring the sound of birds to more than 5,000 locations across the UK.
They include Westfield Shopping Centre in London, the National Assembly for Wales and Wales Millennium Centre, Murrayfield and Hampden Park stadiums in Scotland, the V&A Dundee and Lincoln Cathedral.
All Co-op stores, along with Cotswold Outdoor stores, Lush in Belfast and the Weirdfish stores will be playing birdsong.
Yorkshire venues involved include Leeds University, Cotswold Outdoor shop in Leeds. PD Ports (Port of Hull) and all Co-op stores.
BT call centres in Swansea and Cardiff will play birdsong to their teams throughout the day and Barratt Homes will be changing their hold music to the sound of singing birds.
On the transport network, London Underground stations, all Translink rail stations in Northern Ireland and half a dozen Transport for Wales railway stations will be taking part.
Rebecca Munro, the RSPB's director of communications, said: "Earlier this year Let Nature Sing got the public talking about what birdsong means to them and the shocking fact that the UK has lost over 40 million birds in just half a century.
"We all need birdsong in our daily life, but our natural world is in crisis, our wildlife is falling silent."
She said recent international reports delivered concerning findings on the state of the natural world and impacts of climate change, while the most recent "state of nature" report revealed half the UK's bird species are at risk.
"When looking at the evidence it is no surprise to see that more people recognise that something is not right with our natural world, and that the public feel strongly that addressing climate change and the environment should be a top issue for today's politicians looking to create a legacy future generations will be proud of," she said.