Animal welfare campaigner Chris Packham has described the illegal killing of birds of prey as "out of control", after another death in Scotland.
The Springwatch presenter highlighted the case of a hen harrier which was seriously injured when it was trapped in South Lanarkshire, leading to it being euthanised.
In May, one of the birds was found dead in an illegally set trap on the border between two estates in Perth and Kinross.
This was followed by large publicity about two golden eagles whose tags had stopped transmitting in April near Dunkeld.
Another hen harrier's death was also recently reported in South Lanarkshire.
Packham said: "This despicable crime marks a most depressing day for raptor conservation in the UK and undoubtedly the darkest day for the whole shooting industry.
"It's out of control, obviously beyond any form of self-regulation, and is tolerant of an utter contempt for the laws which are meant to protect our wildlife."
There have been at least 70 confirmed raptor persecution crimes on and close to a number of grouse moors in the South Lanarkshire region over 15 years, according to RSPB figures.
The male hen harrier highlighted by the 58-year-old was said to have suffered serious injuries after being caught in a spring trap illegally-set next to its nest.
Its lower leg was almost severed off and his injuries were so severe that vets had to euthanise him.
The bird had been found in great distress by members of the Scottish Raptor Study Group, who were undertaking routine raptor monitoring on May 11.
A second trap, also illegally-set, had been placed on the harrier's nearby nest.
The nest contained two eggs, but there was no sign of the breeding female.
A Police Scotland spokeswoman: "We can confirm that the death of this hen harrier was reported to Police Scotland and our enquiries are continuing."
Scottish Gamekeepers Association (SGA) chairman Alex Hogg said: "Setting a trap illegally to catch a bird of prey is simply not acceptable.
"The SGA wholeheartedly condemns the actions of whoever has perpetrated this crime and hope the police can gather evidence to enable the courts to do their job.
"Scottish Government, working with Police Scotland, have powers under present legislation to deal with crimes such as this."
A spokesman for Scottish Land and Estates said: "We utterly condemn all forms of wildlife crime including persecution against birds of prey and we are committed to working with police and other partners to find out what has happened."