The RSPB is calling on wildlife fans who enjoy exploring the remote moorlands of the north east to look out for hen harriers, one of England’s rarest birds of prey.

The nature conservation charity has relaunched the Hen Harrier Hotline in the hope of discovering where these birds might be nesting.

At this time of year, the male hen harrier performs his courtship display known as skydancing, involving a spectacular series of swoops and somersaults. If he attracts a female, he then proves his worth as a mate by passing her food offerings in mid-air.

Experts estimate there is sufficient habitat in England to provide a home to around 300 pairs of breeding hen harriers. But last year there were only three successful nests in the whole country, all of which were in Northumberland.

Hen harriers are in trouble because of ongoing illegal persecution. As they sometimes eat red grouse, they are often unwelcome on moors managed for driven grouse shooting. This form of field sport requires huge numbers of red grouse and some game managers resort to illegally killing or disturbing harriers to protect their business.

The RSPB is calling for the introduction of a licensing system for driven grouse shooting, which would help stamp out illegal persecution and improve standards in the industry.

Amanda Miller, conservation manager for the RSPB in northern England, said: “The hen harrier is one of our most graceful and spectacular birds of prey but it remains on the edge of extinction in England. If you see a hen harrier, please let us know by contacting the hotline. If we now where birds are breeding we can deploy round-the-clock protection to give the nest the best chance of success. We can also fit satellite tags to the chicks so we can find out more about where they go after they fledge and launch an investigation if they disappear.”

Male hen harriers are an ash-grey colour with black wing tips and a wingspan of just less than a metre. They are also known as ghostbirds because of the paleness of their plumage.

Female hen harriers are slightly larger, are owl-like in appearance, and have a mottled brown plumage, which camouflages them when they nest on the ground. They have horizontal stripes on their tails, giving them the nickname ringtail and a patch of white just above, on the rump.

The Harrier Hotline number is 0845 4600121 (calls charged at local rate). Reports can also be e-mailed to henharriers@rspb.org.uk. Reports of sightings should include the date and location of sighting, with a six-figure grid reference where possible. A description of the bird’s behaviour would also be useful.