The Turkey oak was reintroduced to Britain three centuries ago
An ancient species of tree is helping Britain's birds survive the effects of climate change, scientists have found.
Frequent early spring weather means blue tits and great tits have been laying eggs ahead of schedule, making it difficult for them to find food.
However ecologists say birds have been feeding on gall wasps, which make their homes in Turkey oak trees, rather than the usual young caterpillars.
The discovery was made during a study by the University of Edinburgh.
It had been feared that the Turkey oak, reintroduced to Britain three centuries ago after an absence of thousands of years, may pose a threat to native plants and animals.
The species was native to northern Europe before the previous ice age, about 120,000 years ago.
But now it appears to be providing the country's birds with a food source.
Dr Graham Stone of the university said: "The reintroduction of Turkey oak and the re-invasion of gall wasps into northern Europe may simply represent restoration of a previous natural situation.
"As the Turkey oak re-asserts itself in its ancient home, it is helping to alleviate some of the effects of the very modern problem of climate change."