Urgent action is needed to protect Scotland's birds of prey, wildlife experts have warned.
Red kites were reintroduced between 1989 and 1992
RSPB Scotland said much more needs to be done to protect raptors, despite better conservation measures having been put in place.
Experts warn that breeds such as the red kite and hen harrier in particular are being illegally killed.
"Illegal persecution of birds of prey in Scotland remains at unacceptably high levels," an RSPB spokesman said.
RSPB Scotland's Duncan Orr-Ewing added: "We have a new Nature Conservation Act in Scotland which gives the police and courts new powers to tackle wildlife crime - however, we now need more trained police officers on the ground to help enforce this legislation."
A report in 2000, by the UK Raptor Working Group, reviewed the health of birds of prey populations across the country and identified the conservation threats they face.
The group was established in 1995 to advise ministers over the issue.
Its report made 25 recommendations for action in relation to the conservation of birds of prey, many of which have been put into place.
However, experts say that five years on there are still areas of concern.
Mr Orr-Ewing said: "We are pleased with progress since the report was published - for example land management incentives to improve bird of prey habitats have been developed - but much more needs to be done if our birds of prey are to recover from Scotland's appalling legacy of human persecution."
Hen Harriers are among those threatened
Professor Colin Galbraith, co-chairman of the UK Raptor Working Group and director of Scientific and Advisory Services in Scottish Natural Heritage, added: "It is very pleasing to see so much progress as a result of the report and the vigour with which organisations now work together is encouraging.
"However, the illegal persecution of raptors remains a disgrace. It is important now to focus our efforts on combating this persecution in conjunction with the landowners, the police and other authorities."
In some areas of Scotland, the re-establishment of the red kite continues to be jeopardised by illegal killing and each year brings further reports of the persecution of other raptors, notably golden eagles and peregrines.
A total of 100 red kites were reintroduced in both the Chilterns and north Scotland over three years starting in 1989.
In 2004, 215 pairs of the bird were recorded in the Chilterns, while in Scotland just 35 pairs were counted.
In 2003, the RSPB reported 143 cases of illegal shooting, trapping or nest destruction of birds of prey and 91 cases of illegal poisoning. The totals include the poisoning of 16 red kites.
Golden eagles are threatened by persecution in parts of mainland Scotland and some local populations face the prospect of significant decline unless action is taken, according to recent research published in the scientific journal Biological Conservation.