Hen harriers are ground-nesting raptors, found on upland heather moorlands and also, during winter, lowlands throughout Britain. The UK population, estimated at 630 breeding pairs in 2010, is heavily concentrated in Scotland, which hosts over 80% of the hen harriers in Britain.
Females are the larger, brown birds with a prominent white rump; males are smaller and a light grey colour with dark wing-tips. Harriers are semi-colonial nesters by habit, lay 4-8 eggs per clutch, with one male sometimes mating with several females across his territory. Males attract females using characteristic aerobatic display flights in spring, leading to the anthropomorphic name ‘Sky Dancer’.
The diet of hen harriers primarily consists of small birds and mammals, and their owl-like facial disk suggests they hunt using sound as well as vision. When red grouse are abundant and visible, especially as chicks, they can form a substantial part of the prey base, putting them into conflict with keepers of managed grouse moors. By the beginning of the 20th century, historical persecution of hen harriers led to them being confined to Orkney and the Outer Isles, but afforestation between 1930 and 1980, legislative protection (1954 and 1981) and conservation efforts led to recovery and again conflict with gamebird interests.
The Joint Raptor Study (1992-1996) was a major investigation into the relationship between grouse and hen harrier numbers. The rapid growth in the number of harriers breeding at Langholm during the study (from 2 to 20 pairs in five years) led to high predation rates on grouse broods, leaving too few grouse to drive for shooting, and removing the incentive to continue moorland management.
This showed that sustainable grouse shooting did not appear to be possible alongside large numbers of nesting hen harriers. The implication was that without using new management techniques to reduce raptor predation, such as diversionary feeding and management of raptor broods, the conflict between grouse moor management and raptor conservation would continue.
Between 2000 and 2006, the Langholm moor saw no keepering (predator control, heather burning) and increasing sheep grazing. GWCT scientists tracked the resulting decline in numbers of ground-nesting upland birds, including the hen harrier, which declined back to 0-2 breeding pairs per year, and the almost complete extinction of lapwings.
The research thus showed that the conflict was genuine and that without moorland management there was a net loss of social and conservation value. Since the Joint Raptor Study, there have been a number of well-meaning attempts to raise the profile of the hen harrier to give it added ‘conservation value’ and to prevent illegal activity. However, these could not find a successful solution because they addressed the manifestation of the conflict and not its root cause.
The ongoing Langholm Moor Demonstration Project (2007-present) is attempting to reconcile grouse moor and raptor interests by re-establishing Langholm as a driven grouse moor in the presence of successfully breeding hen harriers.
Work on finding a conflict solution has been undertaken in parallel in England. In 2006, English Nature kicked off a professional conflict resolution process facilitated by the Environment Council (EC). This process provided vital information for Defra, which in 2012 established the Hen Harrier Sub-Group of the Uplands Stakeholder Forum, bringing together Natural England, the Moorland Association, the National Gamekeepers’ Organisation, the GWCT, the National Park Authority and the RSPB to work towards more hen harriers. The result of this was the Joint Action Plan to Increase the English Hen Harrier Population, published in January 2016.
Photo © Laurie Campbell