Hen-harrier numbers down 33.5%

Ireland’s hen-harrier population has declined by 33.5% since 2000, and this is likely to be down to several factors, including tree-felling, windfams, and turf-cutting. The hen harrier is one of our rarest birds.

Fri, 22 Apr, 2016 - 01:00

Sean O’Riordan

The survey was carried out jointly by the Golden Eagle Trust, Irish Raptor Study Group (IRSG), and BirdWatch Ireland.

Carried out on behalf of the National Parks and Wildlife Service, the survey concluded there could be as few as 108 breeding pairs left.

250 fieldworkers spent 7,000 hours looking for the birds of prey, which are renowned for their spectacular aerial courtship display, known as the ‘skydance’.

The survey was carried out by volunteers, including birdwatchers, farmers, wildlife rangers, foresters, and biologists.

IRSG survey coordinator, Dr Allan Mee, said there was a range of different pressures on the species.

He said these included uncontrolled burning on heather moorlands, the intensification of agriculture, and disturbance by humans.

Dr Mee said it was important to understand why some hen-harrier populations might be declining and a “comprehensive and scientifically robust action plan is needed to maintain, or enhance, existing hen-harrier populations into the future”.

Burning of moorland hinders the birds, because they breed in open, upland habitats, using heather, pre-thicket forest plantations, or scrub, for nesting, while feeding on small birds and mammals.

Hen harriers are regarded as top predators and another factor in their decline could be the loss of food sources in the areas they inhabit.

Other studies have shown similar declines in upland species, such as the curlew and red grouse.

The survey revealed population decline even in some previous strongholds, in special protected areas (SPAs), which the government introduced for them in 2007, at the behest of the EU’s Birds Directive.

SPAs were set up for hen harriers in Clare, Cork, Galway, Kerry, Laois, Limerick, Monaghan, Offaly, and Tipperary.

The latest survey showed an overall fall in their numbers, in the SPAs, of 26.6% since 2005.

“The fact that the SPA network holds 44% of known pairs in the country, which is a significant proportion of the population, shows just how important these areas are in the national context.

The current survey results confirm that populations within parts of the SPA network are declining, and, without intervention, through appropriate management, further declines at certain sites are anticipated,’’ BirdWatch Ireland survey coordinator, John Lusby, said.

The survey will be used by the National Parks and Wildlife Service to identify the main threats to hen harriers and to find solutions for conservation of the species.