HEN harrier chicks have been fitted with satellite tracking devices as part of a conservation project.

The radio tag and solar-powered satelitte device allows the rare bird of prey to be traced within 150 metres anywhere in the world.

In addition to location, the device measures the bird's temperature, how active it is, can help identify where it is roosting and will even tell the experts monitoring it when the bird dies.

Conservation agency Natural England introduced the scheme in the Forest of Bowland following fears that the harrier may be lost as a breeding bird in England.

There are just 12 nests in Bowland Fell which, according to Natural England ornithologist Stephen Murphy who tagged the birds, is something of a sanctuary for the hen harrier.

Elsewhere in England the bird of prey is subject to illegal persecution and the loss of its habitat. There are only two nests across the rest of the country.

Two years ago Natural England tracked a young hen harrier, nicknamed Olivia, and this year ornithologists are tagging her offspring.

Mr Murphy said birds in the area which have previously had the lightweight devices fitted were "doing fine" and the system gave excellent data on them.

He said: "The birds are so mobile, covering 60 miles in a day, for us to glean any knowledge from them we need the radio and satellite devices.

"The birds are so rare and we need to know why."

While the hen harrier is not threatened with persecution at Bowland Fells, elsewhere it is one of the factors affecting the bird.

"In times gone by, the hen harrier was a very common species from the lowlands to the uplands, but another thing which threatens them is habitat loss and change," Mr Murphy added.

While it was easy to protect breeding sites, he said that once the birds left those areas they were susceptible to persecution.

Last month the Government announced moves to boost protection of the hen harrier in England through its inclusion on the list of species and habitats for conservation in the country.

While the bird of prey is extremely rare in England, it is not on the UK's Biodiversity Action Plan list because it is more widespread in Scotland.