A specialist DNA-coded liquid is being used to protect rare birds of prey from people who steal eggs and young birds.
The Smart Water is sprayed near nesting birds, such as goshawks and peregrine falcons, to deter thieves from plundering nests in Derbyshire's Peak District.
The invisible liquid remains on clothing for up three months and can be used to prove they have been in the area.
Birds of prey in the Upper Derwent Valley are among the most persecuted in the country and face extinction locally.
Nest eggs taken
The theft-prevention measures are being put in place by the Peak Nestwatch Scheme and will also include round-the-clock surveillance from CCTV cameras placed on goshawk nests.
Mark Thomas, spokesman for Nestwatch, said, "Some of our most precious birds of prey are being persecuted to the point of local extinction within some of their Peak District strongholds, such as the Derwent Valley.
"We are determined to put a stop to out-dated, illegal practices such as stealing eggs and chicks or disturbing nests.
"These birds are part of our national heritage and delight thousands of nature lovers and tourists who visit the national park each year.
"For far too long, their future has been put in jeopardy - the time has now come to put a stop to the threats facing these magnificent birds."
Last year no goshawk chicks were successfully reared in the Derwent Valley, despite nesting attempts by seven pairs of birds.
In January this year, a man was sent to jail for four months for possessing a goshawk taken from a nest in Hagg Side in the Peak District.
He was the first person in UK legal history to be sent to jail for stealing a wild bird.
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