Threatened grey partridges could be re-established in areas from where they have been lost – by using wild birds as foster parents for captive-reared chicks, researchers have said.

A study shows the method, which taps into the partridges’ unusual instinct for adopting young, gives the released juvenile birds the best chances of survival in areas where suitable habitat has been created for them.

Grey partridges have seen numbers decline by more than 80 per cent in the past few decades, largely due to more intensive farming damaging their habitat as well as an increase in predators such as crows and foxes.

In some areas of the country the species has disappeared entirely.

Researchers at the Game and Wildlife Conservation Trust have been working to find the best ways to re-establish populations through releasing partridges as part of efforts to increase numbers and expand the birds’ range.

Their research revealed that fostering young birds, reared artificially or by bantams, to barren pairs of wild partridges gave the best results of a number of methods for releasing grey partridges into areas where the bird had been largely or wholly lost. Wild adults could be moved from areas where the population is in good shape, or reared birds could have been released and been living wild for some time.

Survival after six months was highest for the fostered birds, at 20 per cent, better than for pairs released in spring, family groups released in autumn or juveniles released to fend for themselves, while their breeding success was also higher.

Francis Buner, who led the research, said: “Because the wild or wild-ish birds haven’t produced their own young, they are very keen to adopt some juveniles from anywhere.”

He said the urge to adopt youngsters was rare among birds, but could be linked to the species’ tendency to stay together in family groups throughout the winter.

And he said: “The reason for the survival and the breeding success of these fostered juveniles is because many of the survival skills needed have been passed on through the parents. If they are wild parents, they have this knowledge.”

Predators including foxes, stoats, crows and magpies also need to be controlled, and supplementary feeding provided. The Game and Wildlife Conservation Trust said that while numbers of grey partridges were declining nationally, in areas where the methods are being used they are paying off.

The trust has produced a set of guidelines for re-establishing grey partridges through releasing, to help farmers and landowners bring the bird back from the brink.

Dr Buner said the research could have implications for other species of gamebird which are in trouble and could benefit from the same technique.