Cumbria Crack

Satellite data reveals Hen Harriers soaring over England

Satellite data from five Hen Harrier which were tagged as part of the Brood Management trial.

Satellite data from an innovative scheme to help boost England’s Hen Harrier population has shed new light on the activities of the birds at the centre of the initiative.

Five Hen Harriers which fledged this summer were fitted with satellite tags as part of a trial of a brood management scheme in which a brood was removed from the moors and transferred to the ‘Ritz’ of raptor rearing facilities. There they were reared in pens before being relocated to moors in the north of England where they were released.

The data from the satellite tagged harriers give conservationists an insight into the flying habits of the iconic bird, an invaluable tool as part of the government-led action plan to boost the harrier population.

The Hen Harriers were tagged before being re-introduced into the wild as part of the Brood Management Trial earlier this year.

One of the male Hen Harriers has travelled close to 1800 miles since it was tagged, averaging approximately 55 miles per day. The bird travelled as far west to the coast of southern Ireland, went on to Southampton, London and then up to Wales.

The other birds all have all remained closer to home in the north of England.

Two of the birds’ tags have currently stopped transmitting, raising obvious concerns regarding their wellbeing. Investigations are underway to establish the whereabouts of the birds. The tags are solar powered, which can result in stretches of time where no data is transmitted, and have malfunctioned in the past with tagged birds being spotted from the ground or the transmitter suddenly retransmitting.

A Hen Harrier visiting a feeding station earlier this year

Amanda Anderson, Director of the Moorland Association, which is a partner in the brood management scheme trial, said: “This data provides a fascinating insight into the behaviour of these captive-reared young harriers. They appear to have integrated very well and their behaviour seems the same as totally wild tagged harriers. Most of the birds have been content to fly around the uplands and grouse moors which is territory they know and like. The adventures of the bird which travelled further afield are extraordinary and show that the species is quite capable of covering vast distances.

“Moorland Association members are enthusiastic participants in this scheme and extensive efforts are ongoing to trace the two birds which have stopped transmitting. The areas to search are massive over difficult moorland terrain hunting for a well camouflaged bird the size of a big crow. Whilst it is expected that at least 50% of birds will succumb to natural causes of death in the first 6 months we very much hope to find the birds alive or at least find them to establish cause of death.”

Andrew Gilruth from the Game & Wildlife Conservation Trust added: “It is already well known that Hen Harriers fly south to overwinter in Wiltshire and Hampshire but this technology reveals that these young birds appear perfectly content to silently move across vast swathes of the country, without anyone appearing to have the faintest idea.”

2019 has been a hugely encouraging year for Hen Harrier with a total of 15 nests, 12 of which were successful in fledging young and a total of 47 chicks fledged – a record breaking total- and the large majority on grouse moors.

Earlier this year as part of the Defra Hen Harrier Recovery Plan, Natural England issued a licence permitting the trial of a brood management scheme of Hen Harriers with the long-term aim of increasing their numbers across England.

The licence permits the removal of Hen Harrier eggs and/or chicks to a world-class dedicated hatching and rearing facility, where they are reared in captivity, before being transferred to specially-constructed pens in Hen Harrier breeding habitat, from which they are then re-introduced into the wild in the uplands of northern England. This intervention may only occur where Hen Harrier nests have reached an agreed density.

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