Hen harrier Circus cyaneus, adult female perched on heather at Loch Gruinart RSPB reserve, Islay

Hen harrier persecution

The hen harrier, relative to its population, is considered the most persecuted bird of prey in the UK.

Declines in population

The hen harrier has suffered a huge decline during the 19th century and became confined to Orkney until the 1930s when new forestry plantations provided suitable habitat to allow the recolonisation of mainland Britain.

The last hen harrier survey in 2004 indicated that the population across the UK as a whole had risen to 749 pairs (up from 521 pairs in 1998), but there had been significant decreases in areas with a concentration of grouse moors.

In 2008, breeding figures for hen harriers in England showed there were just 17 breeding pairs (22 in 2006), 10 of which bred successfully, producing 31 fledged young. Although the final figures are not yet confirmed for 2009, from initial estimates of breeding hen harriers in England, this year is giving all the signs of being an extremely poor year.

Research by the RSPB has shown that the number of hen harriers killed in Scotland (on average 55-74 females each year) far exceeds the number of reports received by the RSPB. Most of the persecution of hen harriers is believed to take place on private land, and therefore goes unwitnessed and unrecorded.

Human interference

Human interference was recorded on 48 per cent of estates studied and the number of young produced each year was three times higher on non-grouse moors compared to moors managed for grouse shooting. Survival of breeding females on grouse moors was half that on other moorland. The total disappearance of hen harriers from some traditional nesting areas indicates that shooting and destruction is the number one factor affecting the conservation status of this species.

The Joint Raptor Study

The Joint Raptor Study (JRS) was published in 1997. This was a five-year study of the relationship between birds of prey (hen harriers and peregrines) and red grouse. It was undertaken by the Game Conservancy Trust and the Institute of Terrestrial Ecology, and supported by Buccleuch Estates, Scottish Natural Heritage, the Joint Nature Conservation Committee, the Scottish Grouse Research Trust and the RSPB. The study took place at Langholm in Dumfries and Galloway, and a number of other estates.

The JRS shows birds of prey cannot be blamed for the long-term decline in grouse bags. Raptor numbers have increased at Langholm only after 1990 yet grouse bags have declined there since at least 1913.

However, high densities of hen harriers and peregrines made driven grouse shooting economically unviable. The more serious long-term problem is loss of good quality heather because of overgrazing which reduces habitat for grouse and can attract high densities of hen harriers.

The RSPB believes habitat enhancement is critical if moors managed for shooting are to recover their stock of grouse. This is neither a cheap nor a quick solution. In the meantime, providing alternative sources of food for hen harriers appears to significantly reduce the number of grouse taken by harriers during the breeding season.

The JRS also confirms the impact of illegal persecution on birds of prey already shown by the RSPB's own studies. For example, the number of hen harriers at Langholm increased from just two to 14 as a consequence of the ending of illegal persecution. Few other grouse moors show such increases.

Red grouse Lagopus lagopus scoticus, adult male in early morning sun. Cairngorm. Scotland.

Tackling hen harrier persecution

In 2004 the police launched Operation Artemis to crack down on the illegal killing of hen harriers – a major landmark in police initiatives to tackle priority wildlife crime priority issues. In October 2007 operation Artemis was concluded, to be followed by operation Moorwatch. 

In 2009 the government priority of tackling hen harrier persecution was expanded to include all raptor persecution, with five main species being the focus of work: hen harrier, red kite, golden eagle, white- tailed eagle and goshawk.

In December 2008, Natural England published ‘A Future for the Hen Harrier in England?’ the results from the first phase of its national Hen Harrier Recovery Project. Monitoring work since 2002 has shown that the critically low breeding numbers and patchy distribution of the hen harrier in England is a result of persecution - both in the breeding season, and at communal roosts in the winter - especially on areas managed for red grouse or with game rearing interests.

Hen harrier, female at nest of eggs in heather

Skydancer

Hen harrier Circus cyaneus, adult female in flight, hunting, Loch Gruinart RSPB reserve, Islay

Skydancer is an exciting four-year project aimed at raising awareness and promoting the conservation of hen harriers in the north of England.