Scotland Conservationists are calling for new measures to protect birds of prey after the "highly suspicious" disappearance of a satellite-tagged golden eagle.

RSPB Scotland say he is the 12th tagged eagle to go missing in the "black hole" area of the Monadhliath Mountains in seven years and said it is consistent with illegal persecution of the birds.

Data from the two-year old male's transmitter showed the bird had been living in an upland area, mainly managed for driven grouse shooting, north of Tomatin since early last year.

However in mid-December his tag, which had been functioning as expected, inexplicably stopped transmitting.

A police investigation has not discovered what happened to the bird, and no further data has been received from the satellite tag.

The young eagle, fledged from a nest in the Cairngorms National Park, was paired to a two-year-old female, also fitted with a transmitter.

Data from her tag shows she left the same area for several days following the male's sudden disappearance, possibly searching for her missing mate, before returning to the territory.

Duncan Orr-Ewing, RSPB Scotland's Head of Species and Land Management said: "A report published by the Scottish Government last May, prompted by the regular disappearance of satellite-tagged eagles in this same area, provided unequivocal evidence that the sudden disappearance of these birds is highly suspicious.

"This is now the twelfth tagged eagle to go missing in this 'black hole' in just seven years and is entirely consistent with the systematic and ongoing illegal persecution of eagles in this area."

The charity said current legislation and enforcement is not deterring criminals from persecuting birds of prey and called for new measures to tackle the problem.

Environment Secretary Roseanna Cunningham said: "We may never discover exactly what has happened in the case of this latest disappearance. But we do know the illegal killing of Scotland's magnificent birds of prey continues - primarily in areas which are intensively managed for driven grouse shooting."

David Johnstone, chairman of Scottish Land & Estates, said the organisation is "deeply concerned by the assumption by RSPB that this eagle is most likely the victim of a wildlife crime perpetrated on a grouse moor".

He added: "Yet again, we see RSPB acting unilaterally as judge and jury without waiting for those professional experts in the police and the procurator fiscals' office to reach an informed decision as to the actual facts."

The Scottish Gamekeepers Association (SGA) urged anyone with information to contact police.