Neurotic marsh harriers pay a visit

EAGLES, hawks and falcons are the celebrities of the bird world.

Like their human equivalents, some of these raptors are primadonnas, who lose the rag when nosey-parkers or the paparazzi invade their space.

Golden eagles, for example, will skulk off their eyries if someone comes within a mile of them. But Scottish eagles and their Norwegian white-tailed cousins allowed chicks to be taken for Irish re-introduction programmes, without throwing tantrums or deserting their nests.

Another raptor, which used to breed here, would not tolerate such interference; the marsh harrier is likely to abandon its nest if disturbed. Importing harrier chicks isn’t an option, but there’s a chance, albeit a slim one, that the species will return of its own accord. Pairs have taken up residence in the south of the country. The locations are being kept secret; the last thing these neurotic creatures need is an army of bird-watchers prying on them. There are, as yet, no reports of breeding but BirdWatch Ireland is keeping a close eye on the situation.

The marsh harrier is as big as a buzzard but slimmer. Females are brown all over, while males are grey on the tail and wings. Flying low with wings held in a shallow ‘V’, they target birds and other small creatures of freshwater marshes and swamps.

Gordon D’Arcy, in Ireland’s Lost Birds, gives an account of their history. The species has been here for millennia, its bones being found at Bronze Age settlements near Lough Gur in County Limerick. The discovery of remains during excavations at Dublin’s Wood Quay has puzzled archaeologists; harriers are not scavengers and would never come close to a city. The species was still breeding in several Irish counties in the mid 19th century. Then, over 100,000 hectares of wetland were drained, depriving the birds of their habitat. Gamekeepers and egg-collectors exterminated the few that were left and, by 1917, the marsh harrier had ceased to breed in Ireland. Since then, the odd straggler has wandered to our shores. With an increase in numbers in Europe during recent decades, more birds have been coming here. It’s too early yet to count our chickens, but perhaps the marsh harrier will forgive us for past wrongs, and become an Irish breeding species.

The UCD zoologist Tom Hayden remarked that “specialists go to the wall, while generalists inherit the Earth”. and this is certainly true of harriers. The hen harrier, a close relative of the marsh, is a smaller bird, easily recognised from the conspicuous white patch on its rump. Females are brown, males being pale grey. Hen harriers nest on the ground in young forestry plantations close to expanses of blanker bog, from which they roam widely outside the breeding season. Their numbers declined during the bad old days of persecution and lethal pesticide use, but the species managed to avoid extinction.

Now, a new threat has appeared – windmills.

We need to harvest wind energy if we are to solve the global warming problem, but some of the best sites for turbines are in harrier country. Valuable habitat can be destroyed when windmills and access roads are built and disturbance during construction frightens the birds away.

On the other hand, wild creatures get to know their local area intimately and harriers soon become streetwise. They tend to fly low, seldom venturing to the height of turbine blades and, in any case, noise should warn the bird of a windmill’s proximity. If left to its own devices it becomes fairly indifferent to human presence; a Norwegian pair even nested within 20 metres of a busy railway line.

So, can windmills and hen harriers coexist? It’s a controversial question and the jury is still out. As scientists say when they kick to touch, it’s a topic which “needs further research”.