The red kite, one of Britain's most spectacular birds of prey, was persecuted in Victorian times, and by the 1930s only 10 breeding pairs were known to exist, all in a remote part of North Wales.

In 1989, a breeding programme was launched in several parts of Britain, in a partnership between the Royal Society for the Protection of Birds (RSPB) and landowners.

Harewood House, with extensive countryside grounds to the north of Leeds, was chosen for the re-introduction of around 16 breeding pairs.

This year, the number of breeding pairs in Yorkshire increased from 47 to 67 – more than 40 per cent – with the number of fledglings rising to 115 compared to 79 last year.

The birds have become a common sight in the Harewood grounds, delighting visitors with their distinctive swoops and forked tails.

Overall, the number of breeding pairs has increased from the 1930s low of 10 to 1,200.

The birds are, however, still vulnerable. Several in Yorkshire have been killed by poisoning – either accidental or deliberate. The RSPB's latest Birdcrime report revealed 17 of the 49 birds of prey reportedly poisoned in 2007 were red kites – the highest number recorded in a single year.

Red kites are now classified as "near threatened" by the World Conservation Union and the UK's 1,200 pairs represent around five per cent of the world population.

Dr Mark Avery, RSPB director of conservation, said: "The continuing recovery of the red kite is a fantastic success story. It is a truly iconic bird and wherever it has been re-introduced, from the Chilterns to Gateshead to Aberdeen, local people have taken it to their hearts.

"Its return is a testament to what is possible when all sectors of society, conservationists, landowners and the general public, recognise the value inherent in our wildlife and work together to protect and treasure it.

"As a country, we can be very, very proud of what has been achieved over the last 20 years."