Conservation groups are calling for increased efforts to tackle the illegal killing of Britain's birds of prey.

A coalition of 26 organisations, including RSPB Scotland, the National Trust for Scotland, the Ramblers' Association Scotland and the SSPCA, have put their names to the call, contained in a report on the status of these rare and endangered species.

Of the country's 15 raptor species, nine have seen their numbers increase in recent years, with populations of five more now stable, according to the report, On a Wing and a Prayer.

Only the kestrel is declining, possibly because of a reduction in prey after changes in farming practice.

Despite the good news, the coalition warned that illegal activity "remains a very real threat in some parts of the country with a minority of people prepared to shoot, trap and poison birds, including golden eagle, hen harrier, goshawk, red kite and peregrine".

Stuart Housden, director of RSPB Scotland, said: "The turnaround in the fortunes of our birds of prey is a cause for national celebration, and we must not allow the illegal activities of a few selfish individuals to obscure the hard work of so many people.

"That is why the organisations behind this report are calling for the laws protecting birds of prey to be maintained and properly enforced to stamp out illegal killing."

The coalition added it was grateful for "the enlightened efforts of many landowners, conservationists, foresters, and gamekeepers" who have aided the birds' recovery.

Meanwhile, two of the groups representing Scottish landowners have issued a joint statement calling for their members to step up their vigilance over wildlife crime.

The Scottish Rural Property and Business Association and the Scottish Estates Business Group are creating a new index of initiatives designed to protect birds of prey.

Examples include the Glenfeshie Estate in the Cairngorms, where Alma, a young golden eagle, has been fitted with a satellite tracking device, allowing her movements to be followed online.