Sounds of the night

THE night sounds of birds can be powerfully mysterious. If you have never heard a corncrake - and fewer and fewer people, sadly, can actually say they have - the first hearing of that measured, tireless double-ratchet, crex-crex, from somewhere in the long grass comes as a sort of intellectual revelation: the brain works it out before the ears do.

The snipe often saves its drumming" for the twilight of warm evenings, and then the bleating of its rush down the sky, tail-feathers spread, takes on a spooky resonance that belongs to an older culture of country fears. You always remember the first time you hear this: who was with you, what they said ("Bloody hell!" as I recall, from one youthful, boozy night in the Dublin Mountains).

Another night sound I have to sort out for one or two readers almost every summer is a reeling, cricket-like churr, hard to place exactly but somewhere in those bushes - the sewing-machine song of the grasshopper warbler. This secretive little brown bird, migrant from Africa, creeps like a mouse through willow-scrub or thorn-brake, and, as Gilbert White put it, its whispering "seems to be close by, though at a hundred yards' distance; and when close at your ear is scarce any louder than when a great way off..."

The rushy roadside tangles of the west give the grasshopper warbler the dense cover they like, together with plenty of insect food. They are thriving, too, in the younger forestry plantations, where their churring can carry, in the still of the night, for half a mile.

Where conifer forest has been freshly felled, there is the chance - no more than that - of hearing yet another puzzling night-call churring hypnotically across a clearing. The song of the nightjar, rising and falling, was once so widely-known in Ireland that people gave it the name of tairne lin, or spinning-wheel. Today, there may be fewer than 30 pairs coming here from southern Africa to breed - part of a general decline in western Europe - so that the new habitats offered by Coillte's clearings in the woods take on a special promise.

Solitary, nocturnal, scooping moths from the air like a bat the nightjar is a creature of deep fascination for naturalists. In the classification of birds, it comes between the owls and the swifts as a little group of species with nocturnal habits and a great gape to the mouth. Then again, it's built a bit like a cuckoo, with long wings and tail, and has even better camouflage than the woodcock.

"The sitting nightjar," wrote Richard Ussher, who knew them well in Ireland a century ago, resembles a rotten stick covered with lichens and scales of bark. I have seen her with neck out-stretched and eyes open wide before she perceived me, but as soon as she saw me she retracted her head, throwing her beak up, and nearly closed her conspicuous eyes, the wings and feathers being tightly compressed. This attitude of the head is customary with the nightjar for concealment when perched, and makes it look very unlike a bird."

One's chance of seeing it in the air is best at dusk, at the moment when the reeling song swells and abruptly stops. Then, to quote Richard Mabey, who knows the "fern-owl" in the healthy clearings of England's New Forest: "A branch seems to break free and float towards you, and suddenly the fern-owl is glancing over the tops of the trees, narrow wings arched above its back and bouncing as if it were being tugged like a kite-up towards the night sky."

Nightjar, fern-owl also "goat-sucker", a myth oddly preserved in its scientific name, Caprimulgus europaeus. In the imagination of ancients such as Aristotle and Pliny, the bird's enormous mouth was obviously for clamping on to the teats of goats and cows, and the serrated comb on its foot for wiping the drops of milk off the bristles round its bill (actually for brushing off the remains of insects, their wings and so on). The goat-sucking story was one of enduring appeal in parts of rural England and Ireland.

In this island, it loved "low, scrubby woods on hillsides", said Ussher, band heaths bordering plantations. In such places several may be heard churring at the same time.

By the middle of this century it was still considered common in Munster and in Wexford and Wicklow (both in the mountains and sand-hills) and it was a regular summer visitor to the Hill of Howth. In the 20 years up to the 1990s, its breeding declined from 93 localities to only 11 - and Howth, unsurprisingly, is no longer among them.

The nightjar's dramatic decline over the past century has been most absolute through the Midlands and inland Ulster: a few red dots remain on the map, widely scattered round the island's perimeter. In Britain, the "occupied areas" remain concentrated in the warm, dry heaths of the southern counties.

The Europe-wide decline is linked, in general, to habitat loss, disturbance and a decrease in large insects due to the use of pesticides (something far less true of Ireland). But the experience in England is not entirely gloomy. The nightjars seem to have been moving from traditional, bracken-covered heaths and scrub into the undisturbed "wasteland" of recently-felled conifer plantations.

It seems that surviving semi-natural heaths may have become, less suitable - perhaps because tighter control of fires and grazing has changed them. Nightjars like bare ground to nest on - not growing vegetation. In one English conifer forest, the numbers went up dramatically in line with the clear-felling - from 90 pairs in 1974 to some 300 by 1990.

Could it be that Coillte's current swathes of felling, plus warmer, drier summers, will bring some magical resurgence of night-jars in Ireland? Could I, at last, meet the tairne lin, hitherto a visitor only to my dreams?