Police and the RSPB have offered a £1,000 reward to help catch the person who shot an Osprey in East Sussex.
Sussex Police said the young bird, which was tagged in Sweden, was found at Holmes Hill, Golden Cross, with a gunshot wound to its wing.
It was treated by a veterinary specialist but died during an operation.
Mark Thomas, of the RSPB said: "The shooting and subsequent death of this bird is sickening."
He added: "Not only is it an amazing species but the fact it was born in Sweden and was passing through the UK on migration makes the killing a national disgrace".
Ch Insp Martin Sims, of Sussex Police, said: "The protection offered to birds of prey by the law is clear and the police will enforce that legislation.
"Ospreys are fully protected at all times across Europe and anyone convicted of this offence in the UK could face up to six months in prison.
"Together with the RSPB we are jointly offering a reward of £1,000 for information leading to a conviction and we urge anyone with information to come forward as soon as possible, in the strictest of confidence."
The bird was one of three chicks that hatched in the Färnebofjärden National Park, in Sweden in June.
Lina Jansson, of The Swedish Bird Ringing Centre, said: "We are saddened to hear about the death of the Osprey chick, particularly so because it had only been alive for a few months and had made an amazing North Sea crossing before being shot".
Sussex Police said there were 12 reported offences, such as shooting, trapping and poisoning, against birds of prey in Sussex in 2009.