A row has broken out over the whereabouts of a satellite-tagged golden eagle after its transmitter stopped working while over an estate.

The young male bird was fitted with a tag by a member of a licensed raptor study group before it left its nest in summer 2016.

Data allowed RSPB Scotland experts to study the movements of the bird - known as 338 - around Aberdeenshire but the tag stopped working on March 5 with its last recorded position in Glenbuchat, Strathdon.

Ian Thomson, RSPB Scotland's head of investigations, said the tags are very reliable and that "the sudden cessation of transmissions strongly suggests the bird has died".

But North Glenbuchat Estate said it was "shocked by the clear implication" that it may have been involved in the disappearance, adding that a video filmed by its head keeper on Thursday showed the bird flying in the area.

Mr Thomson said: "As soon as we became aware of this bird's disappearance, we notified Police Scotland in line with Protection Against Wildlife Scotland protocols, who concurred that the circumstances were suspicious.

"These tags are very reliable and the sudden cessation of transmissions strongly suggests the bird has died.

"Had the bird succumbed to natural causes, we would expect to continue to receive data and to be able to locate and recover the body of the eagle with ease."

Police investigations on the North Glenbuchat estate found no sign of the bird.

Laura Sorrentino, director of the estate, said: "Our head keeper has 14 years' experience and is as confident as he can be that it is the bird in question as he has seen it on a number of occasions and filmed it last month.

"He was aware of the presence of the bird as it had been in clear sight when the keepers were burning heather.

"The head keeper and two other keepers from the estate offered to help the police and RSPB representatives where they may find the bird they were looking for but visibility was poor on Wednesday."

In 2011, a satellite-tagged golden eagle was found illegally poisoned on the same estate.

This latest disappearance marks the sixth satellite-tagged bird of prey to vanish in the Cairngorms within the past 12 months.

Mr Thomson said: "The circumstances surrounding the disappearance of eagle 338 are similar to a number of previous cases currently being considered by an independent review of satellite-tagged birds of prey commissioned by the Scottish Government.

He urged anyone with information "about the disappearance of this bird to contact the police".

Mrs Sorrentino said they take their legal and wildlife responsibilities "very seriously".

"The estate is shocked by the clear implication that the estate may have been involved in the disappearance of this eagle," she said.

"There was an incident six years ago when a dead eagle was found on estate land and at that time the estate issued a very robust statement condemning the poisoning of birds of prey and emphatically denying any involvement.

"There is no evidence that the estate has been involved in any wrongdoing or criminal activity. As regards satellite tracking, it is interesting to note that Natural England tagged 47 juvenile hen harriers from 2007 to 2014, and of the 47 tracked 37 tags ceased transmitting.

"We have had a new keepering regime since February last year headed by an extremely experienced keeper. We are appalled at the allegations made by RSPB and are in discussion with our legal representatives."