More than half of the U.K.'s rarest birds have seen recent population increases, according to the 10th annual "State of the U.K.'s Birds" report (pdf).

Published by the Royal Society for the Protection of Birds (RSPB) in association with several local conservation groups, the report assesses the status of 210 bird species.

Of the 63 rarest U.K. bird species (those with fewer than 1,000 breeding pairs), nearly 60 percent have seen population increases. They include the osprey, corncrake, avocet, cirl bunting and stone-curlew, all of which have enjoyed the benefits of focused conservation programs.

At the same time, 28 percent of the rare birds have seen population drops. The common scoter, for example, is down to just 52 breeding pairs, and could go extinct in the U.K. in 10 years, according to the RSPB.

Amid this conservation success, 40 percent of Britain's common birds have seen their populations contract. They include the linnet, nightingale, swift, guillemot, starling, house sparrow and red grouse. Skylark numbers have dropped 48 percent since 1970 across the U.K. In the same period, the corn bunting has lost 89 percent of its population and has disappeared from Northern Ireland. Two seabirds, the kittiwake and guillemot, are also in dramatic decline. Reasons for these fall offs vary, but the causes mostly boil down to habitat loss.

Image: A cirl bunting ( Emberiza cirlus), one of Britain's rare birds that has enjoyed a population increase. Via Wikipedia