The Queen has been urged to step in and stop the killing of hundreds of mountain hares on her Balmoral estate in the wake of new evidence of mass culls in Scotland.

Delnadamph, which is part of the Queen's Balmoral estate in Aberdeenshire, has been accused of working with other estates to shoot large numbers of hares. Two culls involving three estates were witnessed towards the end of February, one of which was said to have killed 500 hares.

The allegations have been made by the veteran scientist, Dr Adam Watson, who says he has reliable accounts from eyewitnesses and other informed sources. The two alleged culls are in addition to the mass killing suggested by a photograph of a pickup truck full of dead hares on the Lecht published by the Sunday Herald last weekend.

“In each case, a brutal military-type operation occurred, with scores of quad bikes and snow scooters driving the hares up to armed staff hidden higher up, and frequent bangs from guns,” Watson said.

“These severe killings show no respect for the public or for wildlife under stress during snowy weather.”

Landowners insist that shooting hares is perfectly legal, and doesn’t jeopardise their populations. But Watson argues that mass killings are in breach of European law because they are indiscriminate and damage the animals’ conservation status.

Hares are culled in the belief that this stops them spreading disease to grouse, thereby ensuring that there are more birds available to be shot for sport. But this is also disputed by Watson and conservation groups.

David Windle, chairman of the North East Mountain Trust, which brings together hillwalking and mountaineering groups, was “astonished that employees of the Delnadamph estate were allowed to take part in this cruel and immoral activity.”

He said: “We trust that when the matter is brought to the Queen’s attention, she issues clear instructions banning her Delnadamph staff and equipment from taking part in such severe killings.”

The government’s wildlife agency, Scottish Natural Heritage (SNH), has urged “restraint” managing mountain hares. But despite this “heavy culls of hares have continued on some estates,” SNH mammal specialist, Rob Raynor, told the Sunday Herald.

It was “questionable” whether they were showing restrain, he said. “Until we have more accurate information on hare densities and population trends in these areas, doubts remain over the long-term sustainability of such culling.”

Much of the culling has taken place within the Cairngorms National Park, which has also expressed concern. The park authority’s conservation director, Hamish Trench, said that the balance between management for grouse and other wildlife needed to be “reset”.

Bill Lobban, vice-convener of Highland Council and the councillor for Badenoch and Strathspey, described the evidence used to justify culls as “dubious in the extreme”.

He said: “People who visit our national parks do so for many different reasons but I would suggest that few, if any, do so to witness slaughter on the scale that has been evidenced recently.”

Dr Gus Jones, convener of the Badenoch and Strathspey Conservation Group argued that voluntary restraint wasn’t working. “We are frustrated at the lack of progress being made in improving management of our mountain hare populations,” he said.

Scottish Land and Estates, which represents landowners, dismissed Watson’s allegations as “misleading and inaccurate”.

Tim Baynes, director of the organisation’s Scottish Moorland Group said: “Culling has indeed taken place in the Cairngorms but has been done at all times legally, in accordance with best practice and as per the agreed protocol.”

Balmoral’s factor, Richard Gledson, and Buckingham Palace did not respond to requests to comment.