Legal protections are still not in place less than two weeks from the start of open season.
Campaigners fear Scottish mountain hares could be killed in unprecedented numbers this year ahead of new laws coming into force to protect the species.
Mountain hares were given legal protection last month with the passing of the Animals and Wildlife (Penalties, Protections and Powers) (Scotland) Bill.
However, the Bill has yet to receive royal assent, meaning there will be no legal protections in place when open season for killing hares resumes on 1 August.
It has even been suggested that some landowners and groundkeepers might seek to kill even more hares than usual this year in a bid to drive down numbers ahead of the ban.
In a piece for The National, Greens MSP Alison Johnstone writes: “Although Parliament voted for an end to indiscriminate killing of mountain hares, the fight is not yet over. Shooting clubs have ominously warned our celebrations will be ‘short-lived’, and August will see the start of hare-killing season.
“The RSPB and others have expressed concerns that these enthusiasts will use any delay in implementing the new restrictions to kill as many mountain hares as possible. There are already signs on social media that they are mobilising to do this.”
Campaign group Revive, a coalition of charities and organisations lobbying for grouse moor reform, says the Bill must be fast-tracked before the start of shooting season to prevent a “blood bath”.
Max Wiszniewski, Revive campaign manager, said: “Mountain hare persecution is one of the most disturbing, cruel aspects of grouse moor management so Revive was delighted when the campaign to win legal protection for the species was successful. This could prove to be an empty victory however, if the measures are not put in place urgently to pre-empt the open season which begins on 1 August.
“There is a very real threat that unscrupulous land managers will attempt to wipe out the species, which is already in a state of decline, before the law comes into force preventing them from culling hares.”
Robbie Marsland, director of the League Against Cruel Sports, added: "We are deeply concerned that land managers who seek to control hare numbers will feel compelled to take radical action to persecute hares if they have a window of opportunity to do so before the legal protection is enacted.
“It is imperative that the Scottish Government introduces urgent measures to bring forward protected status to 1 August to prevent open season becoming nothing more than a blood bath and industrial cull of this iconic species.”
The Scottish Government refused to commit to fast-tracking the Bill, and did not say what – if any – measures would be taken to protect mountain hares this year.
A spokesperson said: “As the rural affairs minister made clear during the passage of the Act in Parliament, she intends to give careful thought to how the licensing system can best operate.
“A consultation process with a range of stakeholders will be conducted in this regard, and we will set out our timetable for commencing all sections of The Animals and Wildlife (Penalties, Protections and Powers) (Scotland) Act 2020 in due course.”