RSPB Scotland is appealing for information following the discovery of a hen harrier found to have been shot, and the sudden disappearances, separately, of two young satellite tagged hen harriers. Hill-goers might be in a good position to have noticed something amiss...

A member of the public found the dead female bird on a grouse moor on the Dumfries-shire/South Lanarkshire border near the village of Wanlockhead on 7 June 2019. A post mortem examination of the body confirmed that the bird had died as a result of "penetrating trauma" injuries of unknown cause, with shooting a possibility. The examination also showed that the bird had previously been shot, with a shotgun pellet recovered from the left breast muscle. An investigation by Police Scotland has not identified a suspect for the bird's shooting.

Despite laws to protect them, hen harriers remain one of the UK's rarest and most persecuted birds of prey. From satellite tagging data they are known to be ten times more likely to be illegally killed over grouse shooting moors where the land is managed specifically to raise artificially high numbers of red grouse, than any other land use.

Studies suggest there are only around 575 pairs of hen harrier remaining in the whole of the UK and Isle of Man. The vast majority of these - 460 pairs - are in Scotland, making the population there crucial to the future of the species in the UK.

The two birds that have disappeared in suspicious circumstances were fitted with satellite tags under licence by the RSPB's Hen Harrier LIFE project team this summer while they were still in the nest. Romario, a young male, fledged from a nest on National Trust for Scotland's Mar Lodge Estate, while Thistle, a young female, was tagged on an estate in Easter Ross.

Romario was last recorded on 11 September on a grouse moor between Tomintoul and Grantown-on-Spey, while the last transmission from Thistle's tag was received on 12 October, from another grouse moor, in east Sutherland. Satellite tags are highly reliable, say RSPB Scotland, so sudden stops in transmission give immediate cause for concern.

Since the birds fledged the tags had been tracking their movements as they set out on their own. Romario had made his way slowly north, spending time in western Aberdeenshire, before moving into Moray. Thistle, who had been named by Glasgow school children, headed west to into Strathoykel for almost a month before journeys to the east and north. She then returned to Strathoykel, before again heading east prior to her disappearance.

The latest appeal for information follows the suspicious disappearance of another Scottish harrier tagged by the project being investigated by Northumbria Police. Ada hatched and was tagged in the Scottish Borders this summer and was last recorded in the North Pennines, an area known for bird of prey persecution. When she first fledged she had spent some time in lowland East Lothian before heading south; her tag's last transmission was on 10 October in a grouse moor area near Allendale in Northumberland. RSPB England issued an appeal for information about her last month.

Dr Cathleen Thomas, RSPB's Hen Harrier LIFE Project Manager said: "We're devastated to have lost more young birds in suspicious circumstances. The UK's hen harrier population is in such a precarious position it means that every bird really does count and to have these ones disappear at such a young age is really concerning. Sadly, incidents such as this have become commonplace for our project with tagged hen harriers disappearing at alarming regularity every year, and it's really worrying that a young female bird has been shot."

Duncan Orr-Ewing, Head of Species and Land Management at RSPB Scotland said: "The project satellite tags don't stop transmitting if a bird dies of natural causes. To have them go offline suddenly and without warning strongly suggests the hen harriers have been the victims of crime, as in the case of the shot bird. Scotland is leading the way in the UK in terms of legislation to tackle bird of prey persecution, but continuing incidents such as this show that existing measures are not enough. There needs to be robust regulation of driven grouse shooting if crimes against some of this country's incredible wildlife are to be brought to an end."

• If anyone can provide information about these incidents or any illegal persecution of birds of prey, RSPB Scotland has asked them to contact Police Scotland on 101, or to call the RSPB's confidential raptor crime hotline on 0300 999 0101.

Meanwhile, the conservation pressure group Raptor Persecution UK has branded a wildlife crime enforcement pilot scheme in the Cairngorms National Park a 'waste of time and money'.

The Special Constables pilot, announced over two years ago by the Scottish Government in lieu of a manifesto promise to establish a full-blown Wildlife Crime Investigation Unit, has so far investigated no wildlife crimes in the Cairngorms National Park. At a cost of £28,000 to date, the pilot's five part-time Special Constables have simply been "meeting stakeholders", according to Environment Cabinet Secretary Roseanna Cunningham.

Raptor Persecution UK cites copious evidence that during this time satellite tagged raptors, including a white-tailed eagle and hen harriers, have continued to disappear in suspicious circumstances, while others have been illegally poisoned, and yet others have been caught in illegally-set traps - all in the Cairngorms National Park.

The Scottish Government is currently undertaking an evaluation of the Special Constable Pilot Project, and says it will announce a decision on its future direction "in due course".