Peregrine falcons are protected by law in Scotland

The male and female juvenile birds were discovered by two climbers at the Scottish Wildlife Trust's Longhaven Reserve, in Aberdeenshire, on Monday.

The protected birds were killed, along with a crow, by bait which had been laced with an illegal pesticide.

Constable Lee Watt, of Grampian Police, described the crime as "despicable" and said the birds had been targetted.

The crime would have taken some planning by those responsible, from sourcing the poison to carefully preparing and placing the bait to ensure the best chance of killing the intended targets.

"The placing of this poison in an area frequently used by walkers and with abundant wildlife shows a total and contemptuous disregard for the safety of others," she added.

I've seen a lot of poisoned birds in my time but to see two newly fledged juvenile peregrines in otherwise immaculate condition is dreadful Dave Dick RSPB

Wildlife crime officer Constable George Sangster said peregrines had been the unfortunate victims of persecution for many years.

"There are particular groups who view the peregrine as special enemy and a small proportion of them commit these criminal and wholly unjustifiable acts," he explained.

"I would particularly appeal to these groups to come forward and speak to the police."

He added: "Unfortunately my colleagues and I have seen a worrying trend emerging in the last few years in the north east of Scotland with an increase in the persecution of peregrines."

RSPB Scotland senior investigator Dave Dick, who has assisted police with the initial enquiry, said: "I've seen a lot of poisoned birds in my time but to see two newly fledged juvenile peregrines in otherwise immaculate condition is dreadful."

Peregrines, which pair for life and nest on cliff ledges, crags and quarries, dive or stoop to attack prey, reaching speeds well in excess of 100 mph.

Although the species has recovered from its low level of 30 years ago, the birds are still the victims of persecution and egg and chick theft.

There are only about 1,500 breeding pairs in the United Kingdom, with almost two-thirds in Scotland.

The penalties for the illegal killing of wild birds in Scotland have increased in recent years and those convicted can face up to six months in jail or a �5,000 fine for each offence.