Hedgerows provide shelter and nesting opportunities for tree sparrows
A wildlife expert has said tree sparrows need more help from the public to stop numbers declining.
The bird has always flourished in Nottinghamshire due to the county's rich agricultural heritage.
However, Tim Sexton from Notts Wildlife Trust said: "Despite us having a stronghold [of tree sparrows] they are still declining within the county."
Tim said the drop in numbers is down to the intensification of farming methods and the removal of hedgerow habitats.
Tim added that the public can help tree sparrows by providing supplementary food throughout the winter period and providing nesting opportunities.
"Gardens take up more space than all the nature reserves in the country [so] by people providing nest boxes it gives garden birds a chance to bounce back," said Tim.
The tree sparrow is on the Red List of Threatened Species.
The birds look similar to house sparrows except for a chestnut nut brown cap, as opposed to a grey one, and a black spot on their cheeks
Tree sparrow numbers are larger along the Trent Valley, between Nottingham and Newark. Sherwood Farm Lands and the Idle Valley in Retford also have strong populations
Attenborough Nature Reserve, where Tim Sexton is the assistant manager, also has a healthy population of tree sparrows
This is an inventory of the global conservation status of plant and animal species.
"We've seen declines nationally of up to 97%, a huge decline, it's a real species of conservation concern," said Tim.
"They are fairing quite well in the county.
"[However] we were seeing maximum site counts of 2000 individual birds in the mid to late seventies in Nottinghamshire.
"You compare that figure to 2005-2007 and the numbers drop to 200."
Hedgerows are crucial to tree sparrows, providing shelter and nesting opportunities.
However, with modern farming machinery, field sizes have increased and the hedgerows have been removed.
"[Hedgerows are] the perfect habitat for tree sparrows and without it they can't nest and breed," said Tim.
"Also, autumn crops that are being sown now, rather than the traditional springtime sown crops, leaves very little seed-rich overwintering stubble for the birds to feed on."