The nightingale has undergone a dramatic decline in recent years across the UK.
Hampshire and Isle of Wight Wildlife Trust said in Hampshire just 18 male nightingales had been recorded this year, a significant decline from the 355 birds in 1980.
It says there is a real possibility of the species becoming extinct in the county.
The number of nightingales in the UK has declined by 90% in the past 50 years, but the birds are thriving at the Lodge Hill Site of Special Scientific Interest, a former military base in Kent.
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