Case history: The hen harrier

The following is an edited extract from the RSPB's Peak Malpractice Update 2007...

Over the past 25 years, hen harriers have only nested regularly with any success on the United Utilities Estate in the Forest of Bowland, in Lancashire, where they have been monitored by RSPB staff since 1981.

One or two pairs have nested annually for the past 10 years at the RSPB's Geltsdale reserve on the Northumberland/Cumbria border. However, despite being the subject of nest protection measures, they have frequently suffered deliberate persecution, often by people trespassing on the nature reserve. In the Yorkshire Dales, there have been 26 nesting attempts since 1992, but only seven have been successful.

Hen harriers are birds of open moorland, such as that managed for driven grouse shooting. Unfortunately, across Scotland, hen harriers have become less abundant on grouse moors and in England they are virtually absent. Furthermore, when hen harriers do attempt to nest on driven grouse moors, they consistently fare less well than when nesting on other habitats. A study in Scotland showed that the number of chicks raised by each female hen harrier was three times higher on moors with no driven grouse-shooting (Etheridge et al, 1997).

In England, figures since 1994 show that fewer than 30 per cent of nests on driven grouse moors have been successful, compared to a success rate of more than 65 per cent on other moorland. However, there was some very good news in 2006 when two pairs nested in the Peak District. They were only the second and third pairs of hen harriers to nest successfully in the Peak District for almost 140 years, nesting in and hunting over habitat managed by the sporting tenant. Unfortunately, however, they were only successful thanks to the considerable efforts of conservationists, who provided the female harriers with food following the unexplained disappearance of the two male birds.

Natural England reports that this was not an isolated incident: many hen harriers fail to rear young because adults go missing. Since 2002, nearly 60 per cent of hen harrier nesting attempts on grouse moors in England failed because adult birds disappeared. During the same period, no hen harriers disappeared from 52 nesting attempts in Lancashire's Forest of Bowland, which is managed for conservation and the birds are monitored by the RSPB and Natural England.