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Hen harrier

What action is going on for this species?

The following will give you information on what work has been taking place through the Species Action Framework:

Species background

 The hen harrier (Circus cyaneus) is a medium-sized bird of prey found mainly on moorland. Males have pale grey upper-parts, black wing tips, while females are brown with a long, barred tail. All birds have a white rump.

Why is this on the Species Action List?

It meets criterion 3a of the Species Action Framework as a threatened species which is a focus of conflicts of interest with stakeholders with other objectives (notably game management), and for which coexistence is considered by some to be very difficult.

Hen harriers have long been subject to illegal persecution, notably over some areas of moorland managed for driven red grouse shooting, though in some parts of Scotland there are signs of recovery.  In recent years, considerable scientific research has been undertaken into the relationship between red grouse and hen harriers to try to inform management.  A major study has already shown that providing additional food to nesting hen harriers can substantially reduce the number of red grouse chicks that they take.

A major demonstration project, at Langholm, is planned to determine if and how hen harrier, red grouse and habitat interests can be sustained.

It is a Scottish Biodiversity List species. The hen harrier is listed on Annex 1 of the EC Birds Directive and is protected under the Wildlife and Countryside Act 1981, as amended.  It has an 'unfavourable' conservation status across Europe.

Habitat, distribution and abundance

Hen harriers breed on moorlands, peatlands and conifer plantations usually below 500m. In Scotland breeding strongholds include Orkney, East Highland, Arran, Islay, Mull and the Uists. The Isle of Man is also a stronghold, with smaller numbers in Wales, northern England, and Northern Ireland. In 2004, there were 749 nesting pairs in the UK. The European population is estimated at 32,000-59,000 breeding pairs.

The species continues to be absent from many areas which are apparently suitable. Although not used for breeding, grasslands provide valuable foraging habitats. In winter, birds move to open countryside (lowland farmland, marshland, fenland, heathland and river valleys).

General ecology

Hen harriers are predominantly ground nesting birds favouring areas of rank vegetation.  The female normally lays four to six eggs between April and the end of May.  The chicks fledge at 37-42 days. Occasionally a male can mate with and provide for two or more females.  Hen harriers feed mostly on small birds and rodents, especially voles.

History of decline, contributory factors and current threats

The hen harrier population declined markedly during the 19th century.  By the early 20th century hen harriers were only found in Scotland, and even here they were virtually absent from the mainland and much of the Inner and Outer Hebrides, surviving in numbers only on Orkney.  By the 1970s, they had recolonised the mainland, but numbers were well below the carrying capacity of the available habitat.  Large declines occurred from 1970-1990, although the UK level was unchanged between 1988-89 and 1998.  Hen harriers continue to decline in northern England, and south and east Scotland, areas dominated by heather moorland managed for grouse shooting, but numbers have increased in parts of west Scotland, including the Outer Hebrides.

The hen harrier has long been subjected to illegal persecution, and is the most intensively persecuted raptor in the UK.  Persecution has persisted even though it has been illegal since 1954; it is the main factor behind the hen harrier's continued unfavourable status in northern England, and south and east Scotland.

In the west of Scotland, and particularly the larger islands, many hen harriers continue to breed within conifer forests where trees have failed to grow or where patches were left unplanted.  A decrease of 70% in the Orkney population over the last 20 years has been linked to reductions in the area of unmanaged grassland.  This population has now largely recovered, due to more favourable spring weather conditions and an improvement in availability of habitat with suitable prey.

The 'Species Lead' at Scottish Natural Heritage

Des.Thompson@snh.gov.uk   Tel 0131 4474784