A rare red kite, which was introduced into northern England last year after a gap of 150 years, has been poisoned.
The kite died instantly after eating the poison
Police revealed on Friday the protected bird, named Flash by pupils who had adopted it, had fed on a rabbit illegally laced with a deadly toxin.
Police on Tyneside said the substance could have had fatal consequences if handled by a small child.
Pupils at Winlaton West Lane Primary School were left devastated after they were told of the gruesome find.
The bird was one of 20 released into the Derwent Valley last summer as part of the Northern Kites project, managed by English Nature and the Royal Society for the Protection of Birds.
It was found in Tynedale next to a dead rabbit that had been laced with the poison carbofuran.
Northumbria Police Wildlife Crime Officer Pc Paul Henery told BBC News: "The bird was being radio tracked and was detected as being fit and well in August 2004.
"We recovered it on 19 October and judging by the condition of the bird it had been in the field for a couple of months.
"The kite had eaten some of the rabbit and died instantly - the poison is so lethal."
The red kites were reintroduced to the region last summer
The bird was found just 100 metres from a footpath and Pc Henery said it would have been easy for a child to pick up.
"This chemical can be absorbed through the skin and would be fatal," he continued.
"It was an approved chemical to be buried under the ground, but now it is not approved and no-one should have it."
Anyone convicted of deliberately killing the bird could be fined £5,000 and face six months in jail.
Officers want to hear from anyone who knows about the incident or who may possess the poison.
RSPB regional director Andy Bunten said: "Sometimes these poisons are put out to kill foxes or crows.
"But the inevitable side product is that birds of prey will happen on them or dogs or possibly, and tragically, a child."