By David MillerBBC Scotland environment correspondent
North Police have searched an estate after the disappearance of the first white-tailed sea eagle to be raised in the east of Scotland in almost 200 years.
The male bird, which was raised in a nest in Fife last year, was fitted with a satellite tag before it could fly.
Police have made searches of Aberdeenshire's North Glenbuchat Estate where the eagle was last tracked to.
The owners of the North Glenbuchat estate are yet to respond to inquiries from BBC Scotland.
Police officers have spent the day searching property on the estate.
A Police Scotland spokesman said: "We are concerned for the welfare of a white tailed eagle and enquiries are ongoing to locate the bird.
"Around April 10, 2014, we became aware that the bird was missing from the Glenbuchat area of Strathdon as there were no further recordings from its transmitter.
"There is concern for the welfare of this very rare bird.
"As a result searches have been carried out in the area on both land and within premises."
In recent years, several satellite tagged golden eagles have also disappeared in the Strathdon area.
In 2011, the body of one of the birds was recovered at Glenbuchat. Tests showed it had been poisoned.