A rare red kite had to be put down after it was found shot and blinded in County Durham, the RSPB said.
The bird was found alive in Derwent Gorge, near Shotley Bridge, by a member of the public. However, after it was found to be blind it was euthanized.
Since 2010, six kites have been poisoned or shot near Derwent Gorge, including a red kite found poisoned in nearby Muggleswick in 2014.
Police are investigating and have appealed for witnesses.
Like all birds of prey, red kites are protected under the Wildlife and Countryside Act 1981 which makes it an offence to deliberately kill or injure a wild bird.
Those convicted can face an unlimited fine or up to six months in jail.
Howard Jones, RSPB Investigations Officer, said: "It is very sad that this bird had to be euthanized, but there was no alternative.
"Close examination of the bird by experts revealed that its injuries were so severe that it could never have been released back into the wild and it would have had zero quality of life."
Jenny Shelton, from the charity's Investigations Unit, added: "Spring is a crucial time of year when adult kites will be feeding their young, so the death of this bird could have also affected any family it might have been raising.
"Red kites were almost completely wiped out of the UK until they were reintroduced in the 1980s.
"This has been a wonderful success, and most of us enjoy watching these impressive birds. But threats like persecution are preventing them from naturally expanding their range and we clearly have a problem area on our hands here.
"As mainly scavengers, these birds are no risk to anyone. Blasting this bird from the sky was a thoughtless act."
Allan Withrington, of Friends of Red Kites, added: "That anyone could even think about shooting one of these beautiful, graceful birds is beyond my comprehension.
"We are saddened by yet another wildlife crime and look forward to hearing the results of any investigation."