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Species highlight – Hen Harrier

Hen Harrier Male Flying

The Hen harrier (Circus cyaneus) is a medium sized ground nesting bird of prey which breeds between April and July in upland areas of Ireland, typically between 100m and 400m above sea level (Wilson et al., 2015). They spend winter at communal roost sites distributed throughout a broader range, including low-lying agricultural areas, blanket bog and coastal reedbeds. Hen harriers traditionally breed in open moorland, but will also use recently established, open canopy conifer plantations for hunting and nesting (Irwin et al., 2012).

Mature male and female hen harriers differ in both size and colour. Females are brown in colour with a white rump and white tail bars, and are much larger than the males, which are grey and white with black tipped wings. Juveniles of both sexes are similarly coloured to adult females until they begin to moult into their adult plumage at the end of their first year (Wilson et al., 2015).

Hen harriers are a protected raptor species which is listed on Annex I of the EU Birds Directive. Six Special Protection Areas, covering a total land area of 1,671km², have been designated for the conservation of the Hen Harrier in Ireland (Moran and Wilson-Parr, 2015). The most recent national survey estimated there were 108 – 157 breeding pairs during 2015, a decline of 8.7% from the 2010 survey. The main pressures and threats facing Hen harriers are forestry, predation, loss of habitat, non-intensive grazing, recreation and roads (Ruddock et al., 2016). Hen harriers are widely distributed within Ireland, however they are particularly concentrated in Cork, Kerry and Limerick (Irwin et al., 2011).

For information about how we can assist you with Hen harrier surveys or ecological monitoring, please contact:

Fiona Mc Auliffe (


Paul Byrne (


S., Wilson, M. W., Kelly, T. C., O’Mahony, B., Oliver, G., Troake, P. and
O’Halloran, J. (2011). The breeding biology of Hen Harriers Circus cyaneus in Ireland over a five
year period. Irish Birds, 9(2), 165-172.

Irwin, S., Wilson, M.,
O’Donoghue, B., O’Mahony, B., Kelly, T. and O’Halloran, J. (2012). Optimum
scenarios for Hen Harrier conservation in Ireland. HENHARRIER, School of
Biological, Earth & Environmental Sciences, University College Cork.

Moran, P. and Wilson-Parr, R.
(2015). Hen Harrier Special Protection Area (SPA) Habitat Mapping Project 2014.
Irish Wildlife Manuals, No. 83.
National Parks and Wildlife Service, Department of Arts, Heritage and the
Gaeltacht, Ireland.

Ruddock, M., Mee, A., Lusby,
J., Nagle, A., O’Neill, S. and O’Toole, L. (2016). The 2015 National Survey of
Breeding Hen Harrier in Ireland. Irish Wildlife Manuals, No. 93. National
Parks and Wildlife Service, Department of the Arts, Heritage and the Gaeltacht,

Wilson, M., Fernández-Bellon,
D., Irwin, S. and O’Halloran, J. (2015). The interactions between Hen Harriers
and wind turbines. WINDHARRIER, School of Biological, Earth & Environmental
Sciences, University College Cork, Ireland.