A third of all satellite-tagged golden eagles in Scotland die in suspicious circumstances, scientists say.

Scottish Natural Heritage (SNH) found 41  birds vanished over a 12-year period, the majority on land used for grouse shooting.

Plans to give greater protection to golden eagles have been announced in response to the study.

The Scottish Gamekeepers Association (SGA) said it made for "difficult reading".

Environment secretary Roseanna Cunningham said: "The findings of this research are deeply concerning and will give rise to legitimate concerns that high numbers of birds of prey continue to be killed in Scotland each year.

"There is every reason to believe that similar levels of persecution affect untagged golden eagles, as well as those we are able to track via satellite tags.

"We have already targeted wildlife criminals, and those who sanction such crimes, by introducing measures such as vicarious liability and restrictions on the use of general licences.

"But Scottish ministers have always said they would go further if required - and that is what I am doing today."

The new measures include the creation of an independent group to examine the impact of grouse moor management.

Police Scotland will be given greater resources to investigate wildlife crime and special constables will be introduced in the Cairngorms National Park.

The Scottish Government has ruled out giving greater powers to the Scottish SPCA.

"This report identifies specific problem areas which will allow Police Scotland to adopt a targeted approach and I would also encourage members of the public to report any suspicious activity to the police," Ms Cunningham added.

SNH's report found satellite tagging does not contribute to the deaths of birds and ruled out any connection to wind turbines.

A spokesman for the SGA said the organisation "condemns" the killing of eagles but criticised the study's methodology.

"Although this study assimilates 12 years of evidence and makes difficult reading, it does acknowledge recent improvements in some grouse moor areas previously associated with suspected persecution," a spokesman said.

"This change has contributed to the overall betterment of the golden eagle's conservation status, as recently reported.

"That said, problems clearly still exist in some hotspot areas and, in our view, this can only be tackled by all partners having access to the same telemetry data in order to arrive at shared and targeted solutions."

He added: "If this had been happening over the past decade, there is a high likelihood these problems could have been tackled satisfactorily before now.

"The SGA does not believe the report adequately tackles the threat wind farms pose to raptor species as there is a significant amount of published data from other countries which show a negative correlation between bird survival and turbine strike.

"However, that is not an attempt in any way to detract from the report's findings."

SNH studied the movements of 131 young golden eagles between 2004 and 2016 and found 41 had disappeared in what it called "suspicious circumstances".