Trills spill from a warbler in the wood

THE trees and bushes on the acre are thickening up most gratifyingly this summer, so that soon I shall be like one of my own rare species, glimpsed briefly in glades among thickets. Not surprisingly, the new leaves are gathering in other odd birds as well. One morning last week I was tantalised and excited by a hugely energetic torrent of song that was switched on invisibly whenever I, passed beyond a certain point on the path.

Some of this rushing medley was harsh, scolding, buzz saw stuff, but mixed in with it were musical trills, riffs and rattles of apparently endless improvisation, along with snatches of notes borrowed, I could swear, from other birds around the alarm calls of blackbird and stonechat were two I recognised.

It was clearly a territorial advertisement - but what was the bird? I found it perched high on a fuchsia twig, a little, brownbacked warbler with a creamy stripe over its eye, neck tilted and beak stretched wide for minutes on end.

I was surprised that a sedge warbler, not long in from tropical Africa, should prefer to set up home in a tangle of fuchsia bushes rather than beside the reeds of the salt marsh at the bottom of the hill. But sometimes this species seems to breed in a drier habitat: conifer woods, for example - and yes, there's a shelter belt of young spruces pressing up against the fuchsia.

That astonishing vocal performance is well documented. A complete song pattern, lasting well over a minute, can contain over 300 syllables, with complex sets of repetitions and alternations. One bird on record was still introducing new syllables after more than 20 long solos. As for imitations, the sedge warbler's mimicry of other birds is famous. It also sings at night, and in England is sometimes confused with the nightingale.

The other surprise of the week was the bright little bird, flecked boldly with yellow, seen at evening alone on the lawn. It bent down a dandelion stem with one, delicate claw and methodically peeked the seeds from the "clock".

Thus, our first siskin. Some lucky, people have these finches plentifully all winter, especially in gardens with birches. They feed eagerly at the blue tits' nutbag and lord it over everything else at the bird table. But in spring the siskins fly off to breed in their natural habitat, the conifer forest.

It was the rise of spruce plantations in Britain and Ireland that drew this species from its stronghold in Scandinavia and the old pine forests of north east Scotland. As recently as the 1970s the siskin was still quite a scarce bird in the west of Ireland, but now there is Sitka spruce everywhere even on our acre (where, mixed in with many kinds of broadleaf tree, it gets the chance to look beautiful).

Siskins turn to plant seeds when spruce and pine seeds are scarce, but I think our visitor was Just a casual wanderer from the forestry over the hill. Siskins like, to breed in little colonies, with the nests of two or three pairs grouped loosely together at the tops, of conifers.

Siskins and crossbill are two of the birds that have actually spread in Ireland because of the conifer plantations. Many other native birds take advantage of the cover and extra food when the trees are young. But most mature pine forest remains a hushed and lifeless maze, with distant birds twittering invisibly among the topmost branches.

The thought that things might be done differently is encouraged by the research of two scientists in the Zoology Department of University College, Cork.

Dr John O'Halloran and Professor Paul Giller are looking for, ways to enrich the wildlife of new forest plantations and improve the biodiversity of those we already have. They are study birds and fish in forests in south west, both as good indicators of biodiversity and of their interest for other users.

In developing new forests, trees can be fitted to the landscape in ways that maximise biodiversity. Existing forests can be improved by, for example, increasing the area of woodland edge, the richest zone for the greatest variety of wildlife. Nest boxes on the trees add woody debris in forest streams are other simple ways to improve the range of species.

The UCC project is part funded by COFORD, the National Council for Forest Research and Development. It is one of a whole range of ecological projects described in the Council's new Directory of Forest Research in Ireland.

How encouraging to know, for example, that the first pilot study is under way, on a couple of hectares of mountain in Killarney National Park, aimed at restoring native woodland and wildlife to parts of our over grazed uplands.

Dr Rory Harrington and Dr Tom Bolger, both of UCD's Zoology Department, have already started collecting local species of native trees for this exciting Irish experiment in "restoration ecology", echoing ventures already under way in the Scottish highlands.

ANOTHER UCD project, this time in the Department of Environmental Resource Management, clearly anticipates the next big crunch in Coillte's environmental impact. The state forestry company means to clear fell huge tracts of conifers on blanket peatland in the west. It will do it mechanically, of course, which could wipe out - or squeeze out any soil improvement resulting from aforestation. It could also unleash a deluge of peat silt to choke the fishing rivers downstream.

UCD will at least be watching what happens. For its part, Coillte is busy developing "environmentally friendly harvesting machinery - and studying how the Japanese do it, swinging tree trunks down the mountainsides by cable.