THE majority of grouse moor owners are accused of producing a higher number of birds for shooting than is naturally sustainable to the detriment of other interests on the land, raising important questions about how the publicly-subsidised land is managed.

The trenchant criticism comes from three veteran researchers who, they claim, have been prevented by gamekeepers from from continuing a 30-year study into declining bird populations in the Lammermuir Hills in Berwickshire and East Lothian.

The scientists warn that the grouse shooting industry risked “reputational damage”, by banning investigations into why birds are disappearing from southern Scottish uplands.

The three had uncovered dramatic collapses in numbers of lapwings, curlews, oystercatchers and merlins. They said breeding short-eared owls had gone, cuckoos were rarer and there were fewer dippers and sandpipers.

They blamed the falls in part on the “scorched, degraded heather monoculture” created by grouse moor managers. Red grouse were “pampered as never before” making the hills “a much poorer place for other native wildlife”.

They mentioned heather burning and the widespread use of traps by estates as possible causes. They also said that more wind farms and changing weather patterns could have played a role.

Andrew Barker, Ian Poxton and Alan Heavisides started studying birds in the Lammermuirs in 1984. But in an article in the latest edition of the journal, Scottish Birds, they have described how their vehicular access to sporting estates was suddenly stopped in 2015 “after an altercation with gamekeepers”.

They accused estates of “thwarting” the collection of important scientific data. Landowners and gamekeepers “might risk reputational damage at a time when the activities of sporting estates are under increasing and frequently hostile scrutiny,” they said.

“That our presence on these moors ended in such an abrupt manner remains for us a matter of frustration and regret,” they concluded. They quoted one gamekeeper suggesting that their discoveries would put jobs at risk.

“Although we cannot pretend to have provided the answers to why so many bird species are faring poorly in upland areas like the Lammermuirs, we know that the future absence of the data we consistently provided over such an extended period will do nothing to help remedy an increasingly disturbing situation.”

The only wild birds that were not declining were the red grouse, they pointed out. “Whether they even remain truly wild birds is debatable,” they argued.

“What is unarguable, however, is that the intensification of land management in the Lammermuirs, coinciding with major shifts in weather patterns and the industrialisation of the landscape in connection with power generation, has coincided also with a significant slump in the fortunes of nearly all wild birds living there with the exception of red grouse.”

The same pattern was repeated across the uplands wherever grouse were intensively managed for recreational shooting, they argued “We questioned how, and in whose interests, this publicly-subsidised land is managed,” they wrote.

“We concluded that just one thing really matters for the majority of those who own and manage the land today: its capacity to produce higher numbers of red grouse for recreational shooting than are naturally sustainable. The interests of everything else appear subsidiary.”

The article was described as “poignant” by the Raptor Persecution UK blog. The authors had previously concluded that an increase in heather burning “had probably had a detrimental impact” on merlins – but not illegal persecution.

The Lammermuirs Moorland Group, which represents landowners, pointed out that the authors admitted they had written an opinion piece, rather than a balanced scientific approach to their study.

“They also note there can be no evidential link established between moorland management in the area and any declines they may have recorded,” a group spokesman told the Sunday Herald.

A recent study of merlins in England found that 80 per cent were on grouse moors. “So it is clear that grouse moor management, overall, helps provide a suitable nesting environment for these birds,” the spokesman said.

“There can be multiple reasons or factors at play for regional declines of any species.”

The spokesman also criticised the researchers’ account of their ban. “Walking access to the estates remained available to the group at all times, like it does to all members of the public,” he added.

“It is surprising that privileged vehicular access was such an issue when their article states their opposition to these access tracks. Prior to the disagreement over vehicle access, the group had never published such views as those expressed in this commentary.”