Habitat changes leave the twite living on a wing and prayer

Large numbers of twites have disappeared from Caithness and Sutherland.

The Royal Society for the Protection of Birds has been shocked by surveys this winter which showed that only 300 twites have been found in the areas - a huge fall on a 1998 study which estimated the population to be close to 6,000.

Experts believe they may no longer be finding enough food to survive.

The overall UK twite population is estimated at around 10,000 breeding pairs, with 9,500 of those in Scotland.

They are found mainly in the crofting areas of Caithness, Sutherland, Orkney, Shetland and the Western Isles, as well as northern England and north Wales. Caithness and Sutherland are particularly important areas for twites, as one-third of the UK population has previously wintered there.

Those that breed in the area are joined by twites coming in from Orkney, Shetland and the Western Isles.

An RSPB spokeswoman said: "Some other flocks are found in Aberdeenshire and on the Moray coast, but not in such significant numbers as in Caithness and Sutherland, hence the level of concern that the survey this year is picking up such low numbers."

She said the birds bred in moorland in summer and gathered in large flocks over winter, in areas where they could find the fine seeds they required to survive. Historically, these have included grasses around costal dunes, machair and weedy turnip fields within cultivated areas.

Throughout the 1990s, stubbles such as oil-seed rape or linseed supported the birds as changing agricultural practices saw a decline in weedy turnips.

The RSPB spokeswoman added: "The survey may indicate that the birds are no longer finding the food source they require in Caithness and Sutherland."

Research is now being carried out into the birds' breeding requirements, where they like to nest and what they are feeding on. The studies will also examine habits during the winter.

Kirstin Carmouche, an assistant conservation officer with the RSPB, said: "We've been working with the ornithologists who undertook the original survey.

"Together with RSPB staff and a team of volunteers, we have been out this winter, trying to track down the twites, but are turning up relatively few."

The twite, Carduelis flavirostris, is a member of the finch family and is about 12-14cm high.

In winter, male and female birds are a buff colour with dark stripes around their heads and underside and a white belly.

They are commonly found in flocks of up to 1,000 with other birds such as greenfinches, goldfinches and linnet.

RED ALERT FOR THREATENED BIRD SPECIES

LEADING conservation organisations have reviewed the populations of 247 species of birds and placed them in red, amber or green categories, depending on their rarity.

Forty species are red-listed, meaning they are globally threatened - those whose population or range has declined rapidly (by more than 50 per cent) in recent years and those that have declined historically and not shown a substantial recent recovery.

They include the white-tailed eagle, capercaillie, hen harrier, black grouse, corn bunting, Scottish crossbill, song thrush, yellowhammer, corncrake, skylark and the house sparrow.

While corncrake numbers remain low on the Scottish mainland, they have doubled on islands such as Iona, where the National Trust for Scotland is a large landowner and has worked hard to increase the numbers of this species.

Perhaps surprisingly, several woodland birds now feature on Britain's red list, indicating that there has been some deterioration in this habitat, and two urban birds, the house sparrow and the starling, have been added to the red list because of a long-term decline.