The number of mountain hares on moorlands in the eastern Scottish Highlands has fallen to less than one per cent of the level recorded more than 60 years ago, according to a long-term study.

The Centre for Ecology & Hydrology and the RSPB teamed up to study counts of the animals over several decades on moorland managed for red grouse shooting and nearby mountain land.

From 1954 to 1999, the mountain hare population on moorland sites decreased by almost five per cent every year, the study found, saying the long-term decline was likely to be due to land-use changes such as the loss of grouse moors to conifer forests.

However, from 1999 to 2017 the scale of the “severe” moorland declines increased to over 30% every year, leading to counts last year of less than one per cent of original levels in 1954, researchers said.

On higher, alpine sites, numbers of mountain hares fluctuated, but increased overall until 2007, and then declined, although not to the lows seen on the moorland sites, the study noted.

The report stated: “The study found long-term declines in mountain hare densities on moorland, but not alpine, sites in the core area of UK mountain hare distribution in the eastern Highlands of Scotland.

“These moorland declines were faster after 1999 at a time when hare culling by grouse moor managers with the specific aim of tick and LIV control has become more frequent.”

Gamekeepers and estate managers claim culls limit the spread of ticks, protect trees and safeguard fragile environments, and a policy of voluntary restraint is in place.

However, campaigners believe the practice is cruel and unnecessary. The research paper, being published in the Journal of Applied Ecology, stated: “On moorland sites, a long-term decline (4.6% per annum) from 1954 to 1999 increased to 30.7% per annum from then until 2017, with a density index falling to <1% of initial levels after 2008.

“Before 1999, declines were associated with conifer planting and were least severe where heather burning characteristic of grouse management was present. Grouse moors had the highest rate of decline after 1999.”

The findings were revealed after the annual grouse shooting season got under way yesterday.

Lead author of the study, Dr Adam Watson of the Centre for Ecology & Hydrology, said: “Having counted mountain hares across the moors and high tops of the eastern Highlands since 1943, I find the decline in numbers of these beautiful animals both compelling and of great concern.

“We need the Scottish Government and Scottish Natural Heritage to take action to help these iconic mammals of the hill – I hope they will listen to the voice of scientific research.”

The RSPB said urgent action is needed to protect mountain hares.

Duncan Orr Ewing, head of species and land management at the charity in Scotland, said: “We consider that large-scale population reduction culls are both illegal under EU law and unwarranted as a method for controlling grouse disease.”

But the Scottish Moorland Group said the research was “out of kilter” with other respected studies and said RSPB Scotland was continuing “its political campaigning” against grouse moor management.

This view was supported by a spokesman for The Scottish Gamekeepers Association, who said: “This work is largely at odds with what is being seen on the ground in grouse moor areas, where hare numbers – in good breeding seasons – remain very, very high, sometimes reaching densities of up to 200 hares per sq km.

“Data held by GWCT shows the number of hares taken on grouse moors shows no overall discernible trend since 1954, despite the claims by those seeking to legislate against grouse shooting that culls have been escalated to protect grouse. The average annual hare cull of 25,000 represents only 7% of the estimated population.

“Whilst on Scottish grouse moors hare numbers remain amongst the highest in Europe, we know there are campaigning wildlife charities, looking after hundreds of sites, with suitable habitat but no mountain hares at all. That revelation may shock and will become clearer to the public and government when the new counting methods are widely adopted, which is what the SGA is calling for.”

Meanwhile, grouse shooting season has opened, but some estates in Scotland have cancelled shoots due to exceptional weather, the March cold spell and the dry summer, hitting breeding stock.