A project to bring red kites back to UK skies is now sending chicks to help conservation efforts in Spain, which supplied birds for the highly successful reintroduction scheme.

Conservationists say the red kite reintroduction is the UK’s most successful bird conservation project to date, and has done so well in its 33 years that English chicks can now be donated to efforts to help the birds in Spain.

Red kites, a large bird of prey that largely feeds on carrion and worms and cuts a distinctive silhouette with wing tips that look like splayed fingers and a forked tail, were common city scavengers in medieval London.

Shakespeare writes of a “city of kites and crows” in his play Coriolanus, while their reputation for stealing laundry hung out to dry for their nests gets mentioned in The Winter’s Tale.

But the birds’ fortunes declined in the face of persecution and also egg collecting, and by the 20th century they were extinct in both England and Scotland.

Red kite flying over frosty landscape
A red kite flying over frosty landscape (Ben Andrew/RSPB/PA)

While a small population hung on in Wales, it was not big or healthy enough to recolonise the rest of Britain, even once the species was protected.

A trial reintroduction of red kites to both England and Scotland used birds mainly brought from Spain for the English scheme, and from Sweden for the Scottish releases.

The once-vanished bird is now soaring over countryside, gardens and towns across swathes of the UK, and the population is estimated at 6,000 breeding pairs, with 4,500-5,000 of those in England.

Conservationists say the project has been so successful that red kite chicks can be supplied in return from England back to Spain to help with efforts to conserve the species in that country.

Breeding populations in Spain have declined substantially, mainly due to a legacy of illegal poisoning, which Spanish authorities have taken major steps to address in recent years, wildlife experts said.

While many bird of prey and vulture populations have recovered, the red kite population has remained at low levels.

A collaboration between Spanish and British conservation organisations – and involving some of the people from the original England and Scotland red kite reintroduction projects – is set to supply 30 wild red kite chicks a year for three years from the large healthy population in the East Midlands.

The scheme is being run by Accion por el Mundo Salvaje in Spain, and RSPB, Roy Dennis Wildlife Foundation, Forestry England and other landowners in the UK, with government agency Natural England licensing the project and veterinary support from Zoological Society of London.

This year, all the chicks going to Spain have been collected by Forestry England from nests in the public forests it cares for, as well as from the Boughton Estate in Northamptonshire.

The RSPB’s Duncan Orr-Ewing, who organised the first red kite reintroduction programme in Scotland and is now advising the latest project, said: “The red kite population is confined to Europe.

“Compared to most of our other native birds of prey it has a relatively small global population.

“Following concerted conservation action in the UK in recent decades, this species’ population has greatly recovered.

“It is amazing that we are now able to support conservation action for red kites in Spain and to reciprocate their previous generosity in supplying donor stock for our original reintroduction project in England.”

Natural England chairman Tony Juniper said: “The reintroduction of red kites to England is the most successful raptor conservation story in Europe.

“It’s a clear blueprint for the future of species reintroductions, particularly for some of our most endangered birds.

“I’m hopeful the red kite chicks bound for Spain will flourish in the same way the chicks that arrived to this country a generation ago did, as we support those helping to rebuild the population and the prospects of this magnificent bird in southern Europe.”