Some of the country`s rarest birds of prey species are continuing to be poisoned, trapped and killed illegally, according to an annual report.
RSPB Scotland said 20 birds were deliberately poisoned in 17 separate incidents last year, including a golden eagle, four red kites and seven buzzards.
The report, called The Illegal Killing of Birds of Prey in Scotland in 2011, said many of the animals died after ingesting bait laced with highly-toxic chemicals.
The charity said that while the number of detected poisoning incidents has fallen in comparison to recent years, the act still poses a "significant threat" to Scotland`s birds of prey.
There were 16 other incidents recorded during 2011, including a buzzard which was starved to death in a crow trap and a goshawk's nest which was destroyed, as well as a short-eared owl, two peregrines and three buzzards all being found shot. Most of the illegal killings are said to have taken place in the eastern and central Highlands and southern Uplands, in areas which are managed for driven grouse shooting.
Ian Thomson, head of investigations at RSPB Scotland, said: "Many of these crimes were discovered purely by chance, by walkers or birdwatchers, in remote areas of countryside, it's safe to assume that many victims of illegal killing are not detected or reported.
"While at last there may be some welcome indications that the indiscriminate use of illegal poisons is on the wane, it is clear from this report, and the events of the last few months, with a golden eagle being illegally trapped in Angus, and another found shot in Dumfries-shire, that there is a long way to go before these crimes are eradicated."
Duncan Orr-Ewing, the charity`s head of species and land management, said: "We hope that a decrease in poisoning cases is a trend that continues and is reflected in the return of birds of prey in their former ranges. However, it is deeply concerning that over this same period, there is no evidence of a decline in other forms of illegal killing.
"These crimes can have a devastating impact on the long-term population of rare and slow breeding species such as hen harriers, golden eagles and red kites. There can be no place for these appalling crimes in Scotland in the 21st century."
The Scottish Government has introduced measures designed to tackle wildlife crime in the recent Wildlife and Natural Environment Act 2011, making landowners responsible for the actions of their employees. It means that, in the event of proven illegal activity against birds of prey, landowners could also be liable for prosecution.