GAMEKEEPERS are calling on Scottish Natural Heritage (SNH) to introduce licences to kill pine martens, or face losing the endangered capercaillie – the largest bird of the grouse family – from Scotland for a second time.

The move comes after the fourth national survey into the estimated size of the Scottish population showed a decline of 35% from the previous study.

The new survey estimates the number of individual birds to be 1285, a marked drop from 1980 recorded using similar techniques in 2003/04.

Capercaillie died out in Scotland in the 1700s but were reintroduced from Sweden and, in the mid-1900s, reached levels of between 20,000 and 50,000.

However, since 1970, predation by foxes, badgers, woodland raptors and pine martens has increased dramatically, pushing capercaillie to the brink.

Now the Scottish Gamekeepers Association, is urging SNH to push through licences to control pine marten numbers.

The 5300-strong organisation has argued that using public money to manipulate habitat, while refusing to control the animals that predate capercaillie, represents singular folly.

"We attended a Capercaillie Biodiversity Meeting in Perth in 2001 and told representatives from SNH that, if this was to work, they would have to consider the number of pine marten and other predators," said a spokesman.

"We were told they didn't want to talk about pine marten. Calls have been made to introduce licences to control them and now, 11 years later, this is SNH's chance to redress the situation. We hope sense prevails.

"If licences to control pine marten are not granted, it is highly likely the capercaillie will be lost for a second time in Scotland."

An SNH spokesman said "Pine martens are a protected species and, at a UK level, are one of our rarest native mammal species. However in some areas of Scotland, such as the Highlands, they are more common.

"Pine martens feed on a range of items including insects, carrion, berries, small mammals, birds and eggs. This can include capercaillie eggs."

According to the Scottish Gamekeepers' Association, millions of pounds of taxpayers' money has been ploughed into efforts to save the capercaillie – the Tetrao urogallus – in Scotland.

In 2006 a campaign was launched to increase the population to 5000 by 2010. However, the latest survey concludes that, despite conservation efforts by groups such as RSPB, Forestry Commission Scotland and Scottish Wildlife Trust there has been no rise in the numbers of the distinctive black bird, which is on the conservation red list.