A RARE songbird has tripled in number in 13 years and returned to Wales, The Royal Society for the Protection of Birds said yesterday.

But the Dartford warbler’s population increase can only be sustained and improved if the Government protects the birds’ natural habitat, the RSPB said.

The UK population of Dartford warblers increased from 1,890 pairs in 1994 to an estimated 3,208 pairs, according to a recent survey. The bird has returned to Wales, the Midlands and East Anglia, and there are 85 pairs in the Channel Islands. The population growth is a massive jump from 1963, when just 11 pairs were counted.

Milder winters and the availability of heathland have helped numbers increase, according to the RSPB. The bird has also adapted to new habitats.

The Dartford warbler – or Sylvia undata – is distinguished by its short, rattling warble, and its distinctive buzzing call.

It has a long tail and is about 13cm long, with grey-brown upper parts, a wine-red chest, white belly and red eye-ring.

It is on the “amber” list of conservation concern because of previous population declines.

Simon Wotton, research biologist at the RSPB, said, “This survey is fantastic news for a very vulnerable bird, particularly because it has moved to higher ground not used by Dartford warblers for many years.

“Warmer winters mean the birds are likely to push even further north but they can only do that if there are heathland sites available, which are protected from development.

“If the Government is to help wildlife adapt to climate change it should be assigning more land for the creation of habitats to help birds like these.”