FORENSIC tests have revealed a golden eagle found dead in one of the Angus glens this month was poisoned.

RSPB Scotland said it was an appalling incident involving the species that was recently voted as the nation's favourite bird.

The charity will be seeking support from all Scotland's political parties for stiffer penalties for anyone caught killing eagles.

The bird was discovered after Roy Dennis, of the Highland Foundation For Wildlife, who was monitoring the eagle's movements, became suspicious when the satellite signal remained static for several days. The eagle, named Fearnan, was ringed as a chick in a nest near Loch Tay, Perthshire, in June 2011 and had spent much of its life in Badenoch, before moving to the Angus glens early last month.

Police, who carried out the tests, want to talk to anyone who was in the Glen Lethnot and surrounding areas between November 10 and 25.

Constable Blair Wilkie, wildlife liaison officer for the Angus area, said: "You may not think any information you have is of value to us, but please let us be the judges of that.

"It is also important to stress to the public that in cases where poisoned baits are used to target birds of prey, the poisons present a wider threat. They are, without question, a significant health risk to both humans and animals."

Stuart Housden, director of RSPB Scotland, said it marked a dreadful end to the Year Of Natural Scotland. He added: "We have recently submitted a petition to the Scottish Government asking for the golden eagle to be officially designated as the national bird of Scotland.

"Incidents such as this show very clearly why this iconic bird needs not just our recognition, but also greater protection. We sincerely hope those responsible are swiftly brought to justice and would encourage those with information to come forward."

In the past five-and-a-half years, he said, another four eagles, a red kite and seven buzzards had been shot, poisoned or trapped on sporting estates in the Angus glens. In January, the nest tree of a pair of white-tailed eagles was felled. He said nobody had been prosecuted for any of these offences.

Mr Housden added: "I will be asking the environment spokes­person of all the parties in the Scottish Parliament to take cross-party action to stiffen the penalties for those convicted of such offences and to look again at the regulation of sport shooting. The current state of affairs is unacceptable."

Scottish Environment Minister Paul Wheelhouse said: "The killing of our wildlife is a stain on Scotland's reputation; a reputation on which many of our industries such as tourism, recreation and food and drink rely heavily.

"It is a great regret that such actions undermine the reputation of sporting estates at a time when there has been genuine progress on the part of the majority of estates and gamekeepers. The actions of a small and ignorant minority are extremely damaging."

Mr Wheelhouse said the crime, together with a recent incident where a buzzard was found poisioned north of Bridge Of Allan, reinforced the call he made in July for more work in implementing the measures to tackle the crime. He said he would be following the police inquiry with great interest.

Douglas McAdam, chief executive of Scottish Land & Estates, said: "We are appalled that poisoning is the cause of the death of a golden eagle in Angus. Such illegal acts do untold damage to the rural sector and will not be tolerated by the responsible majority.

"We offer our support to police as they continue to gather evidence about this incident.

"We will be contacting our members and encouraging them to respond to the call for information."

Anyone with information can contact police on 101.