The bird has not been seen for days

The falcon has disappeared from Hanson Quarry at Clee Hill in Shropshire, the RSPB says. It was due to be part of a unique educational project.

The RSPB says a male peregrine falcon was found poisoned in the same part of the county last year.

Dan Farber, from the organisation, said it was "disgraceful" that birds of prey were still being persecuted.

Rat poison

The female falcon was due to have been part of an RSPB project to give an insight into the lives of the birds, from eggs to the fastest animals in the world.

The scheme was ruined last year when the male bird was found poisoned, the RSPB said.

Analysis of the body showed the bird had been poisoned with a chemical used to kill rats.

The RSPB fears the falcon probably ate a deliberately-placed bait laced with the poison.

Natural heritage

The project continued this year however, when a new male peregrine moved into the territory over the winter and paired up with the resident female.

Mr Farber said: "This spring everything looked promising for the birds, the pair had mated and chosen a nest site, but this time the female bird suddenly disappeared.

"Sadly, the female peregrine has not been seen for days.

"It is disgraceful that birds of prey are still persecuted and if this peregrine has been poisoned, the person responsible is depriving the country of its natural heritage and thousands of people of an inspirational experience.