Scottish Raptor Groups

The Hen Harrier is a scarce breeding species in Scotland that has been the subject of a considerable amount of interest over the past 15 years over concerns about its status, conservation, impact on grouse-moors and level of persecution. It is essentially an open country species, in the breeding season showing a close affinity to heather moorland and young forestry plantations with heather ground vegetation in upland areas. It has a widespread but thin distribution, breeding throughout Scotland wherever suitable habitat exists, with the exception of Shetland and Lewis & Harris.

In former times it was a much more commoner bird of the moors, bogs and mires but following the creation of sporting estates during the 19 th century, especially those associated with grouse shooting, it was quickly exterminated in mainland Scotland (Watson 1977). Only on islands such as the Uists and Orkney where grouse-moors were not viable were tiny populations maintained. Two World wars in the 20 th century, the reduction in gamekeepers and the creation of vast forest plantations in the uplands provided a comeback opportunity and the number of breeding pairs has steadily increased, particularly since the 1950s. The largest populations still occur in those regions where driven grouse shooting is not a feasible proposition; particularly the Uists, Orkney, mainland of Argyll and the west coast islands from Mull to Arran (Sim et al . in press). Their scarcity on the grouse-moors of eastern Scotland and the Borders indicate that illegal persecution in these areas is still a major problem (Etheridge et al . 1997) and that gamekeeper's attitude to harriers and their contempt for the law that protects the birds has changed little over the past 200 years.

There have been three national surveys of Hen Harriers in Scotland. The first in 1988/89 estimated a breeding population of 408-594 pairs (Bibby & Etheridge 1993). The second in 1998 located 436 pairs, 76% of UK breeding population (Sim et al . 2001). The third in 2004 revealed an increase to 633 pairs, 79% of the British population (Sim et al . in prep.) and a 32% increase over the 1998 estimate. More surprisingly, this increase was confined solely to the west and far north and that the numbers of breeding pairs in the east and south where grouse-moors are prevalent had all declined.

The Hen Harrier is a popular species amongst raptor enthusiasts and currently Scottish Raptor Study Group members are locating and monitoring around half of the current breeding population. In 2004, 67% of nests located by members produced young with an average of 1.8 young per occupied nesting site across all regions. Hen Harriers face threats from many quarters: uncontrolled heather burning, overgrazing, the maturation of nesting forests and the proliferation of wind-farms in the uplands, all this in addition to the current high level of deliberate killing of adults and the destruction of nests by gamekeepers. However, SRSG members remain committed in monitoring the long-term effects of these activities and land use changes on this iconic moorland species.

Brian Etheridge

References:

Bibby, C.J. & Etheridge, B. 1993. Status of the Hen Harrier Circus cyaneus in Scotland in 1988-89. Bird Study 40: 1-11.

Etheridge, B., Summers, R.W. & Green, R.E. 1997. The effects of illegal killing and destruction of nests by humans on the population dynamics of the hen harrier Circus cyaneus in Scotland. Journal of Applied Ecology 34: 1081-1105.

Sim, I.M.W., Gibbons, D.W., Bainbridge, I.P. & Mattingley, W.A. 2001. Status of Hen Harrier Circus cyaneus in the UK and the Isle of Man in 1998. Bird Study 48: 341-353.

Sim, I.M.W., Dillon, I.A., Eaton, M.A., Etheridge, B., Lindley, P., Riley, H., Saunders, R., Sharpe, C. & Tickner, M. Status of the Hen Harrier Circus cyaneus in the UK and the Isle of Man in 2004, and a comparison with the 1988/89 and 1998 surveys. Bird Study . In prep.

Watson, D. 1977. The Hen Harrier . T. & A.D. Poyser, Berkhamsted

Wing-tagging young harriers in Orkney