A rare hen harrier has disappeared in North Yorkshire, prompting fears it may have been deliberately killed.
The bird of prey was fitted with a satellite tag after hatching in the Peak District in the summer.
It was in the North York Moors National Park on 26 October when the signal was lost.
The bird, named Arthur, is the ninth hen harrier to disappear in suspicious circumstances in the last 12 weeks, according to RSPB records.
The charity had been monitoring Arthur's movements as he flew from the Brecon Beacons in South Wales to Nidderdale.
The bird's last registered location was north of Lowna Bridge, near Hutton-le-Hole, with no body or tracking tag recovered.
More than 30 hen harriers have been tagged in England, Scotland, Wales and the Isle of Man in 2018 by the RSPB.
Despite being protected by law under the Wildlife and Countryside Act 1981, numbers of hen harriers remain consistently low, a spokesperson for the charity said.
Sgt Kevin Kelly, of North Yorkshire Police, said: "This is an unwanted addition to the already concerning and ever-raising numbers of hen harriers that are just 'vanishing'.
"I encourage any information that could help me forward this investigation, these rare birds are one of the jewels in the crown of the English countryside."
In recent months, satellite-tagged hen harriers have also vanished suddenly in the Peak District, north and central Scotland, north Wales and Northumberland.