Hen Harriers struggle to hold their ground on Irish hillsides

THE Hen Harrier (Cromán na gCearc) is a medium sized bird of prey that breeds throughout Europe and across parts of Asia. Ireland is home to the most westerly population of Hen Harriers in the world but their numbers here are under pressure. Male and female Hen Harriers are strikingly different in their appearance, so much so that for centuries it was even thought that they were separate species. The male is arguably the more visually stunning of the two, with bluish silver plumage, white undersides and distinctive black tips to the wings. As with most birds of prey, the female is larger than the male. Females have soft brown plumage with fine markings, a banded tail and a characteristic white rump, which is one of the best features for identification.

Although rare, Hen Harriers are widely distributed throughout Ireland. They occur mainly in upland areas during the nesting season and their specific habitat requirements mean that their breeding range is largely confined to low-lying hills, generally under 300m.

The south-west of the country supports the highest concentrations, particularly Cork, Limerick and Kerry where approximately one third of the national population exist, with parts of Clare, East Galway and upland areas in Laois and Offaly also being important.

Hen Harriers are typically open-country species, traditionally nesting on the ground in heather dominated moorland. However, due to land use and landscape changes and widespread planting of non-native coniferous forests, their nesting preference has largely switched to pre-thicket forest plantation and early growth second rotation forest. They will also nest in dense cover in vegetation such as bracken, gorse or bramble, usually on a sloping hill which is free from disturbance.

The Hen Harrier was once more widespread throughout Ireland but has declined in range and population over the past 200 years. They were widely persecuted during the 19th and the early part of the 20th Centuries, however the population began to recover during the 1950s. By the 1970s the all-Ireland population was considered to be 200 to 300 pairs, but this declined to an estimated 180 pairs by the early 1990s.

The first national survey of Hen Harrier was carried out between 1998 and 2000, and this estimated our breeding population at 102 to 129 pairs. The second national survey in 2005 reported an increase in the breeding population, with between 132 and 153 pairs. The most recent national survey in 2010 recorded 128 to 172 pairs, which highlighted a slight decline of 6.4 per cent in the national population when the increased level of coverage is taken into account. The longest-running study of Hen Harriers in Ireland has shown that, in the Duhallow region of North Cork, their population declined by 80 per cent from 1998-2011, with maturation of forestry cited as the main cause. The fifth national survey for Hen Harriers is being carried out this year – keep your eyes open at dusk as they can be seen flying over marsh or bog land..

A male Hen Harrier rises from the heather with dinner gripped firmly in its talons.