Irish birds doing well but worrying trends taking flight

EMIGRATION has ceased and people are flooding into Celtic Tiger Ireland. The country’s human population is being transformed and so is the landscape.

But how are our feathered friends coping with the changing times?

Do magpies rule the roost and are swallows and song thrushes thinner on the ground, as some people claim?

The evidence for such assertions is mostly anecdotal but now an authoritative report on our birds has appeared. It reveals some problems, but it’s not all doom and gloom.

Each year since 1998, BirdWatch Ireland has carried out a census of birds in the Irish countryside. This island is too large for observers to visit every nook and cranny, so the survey is based on sample areas; 395 study plots, each measuring 1km by 1km, have been selected by project coordinator Dick Coombes. Volunteers from BirdWatch, and rangers from the Wildlife Service, visit each square early in the breeding season, when the early summer migrants are easy to observe. The species found are listed and the numbers of birds estimated. Four weeks later, the squares are surveyed again, so that the late migrants can be included. Counting begins between six and seven o’clock in the morning.

Songbirds are not easy to census and coming up with accurate figures for the more elusive species is virtually impossible. However, absolute numbers don’t matter too much; it’s changes in the populations which are important. Although only a proportion of the birds present in an area may be seen or heard during a visit, the numbers recorded over the entire country, when compared from year to year, should show up any dramatic changes which are taking place.

The results, so far, make for interesting reading. Over the eight years up to 2005, 128 species were seen. The starling, wren and jackdaw are Ireland’s most common birds, but starlings and jackdaws were not found everywhere; wrens robins and blackbirds are more widely distributed. Wrens were found in 98% of squares, robins in 94%. At the other end of the scale, 19 species were recorded in less than 10 squares. Some of these were winter migrants, redwings and fieldfares, which don’t breed in Ireland and had not yet departed for their home countries.

Olivia Crowe, of BirdWatch’s conservation staff, carried out a “trend analysis” for 52 species. For most of these, she found that numbers did not change greatly over the years. “Baddies” such as the magpie and the grey crow are holding their own. So are our tit species There have been worries about the future of the yellowhammer, which is on the Irish Red List. Happily, yellowhammers were found in about a quarter of all squares with no significant change in numbers during the survey period.

Seventeen species showed increases. The numbers of goldfinches, redpolls and bullfinches are up and finches generally seem to be doing well, with an increase of 7% each year. Warbler numbers rose by 4% annually. Stonechats are also prospering. Blackcaps recorded the greatest increase of all; a 25% rise every year.

Although the robin is one of our commonest birds, its numbers are falling, but no-one knows why.

The house martin population has remained fairly stable overall, but a drop in numbers in the eastern counties has been balanced by increases in the south. Its cousin, the swallow, is not doing so well. Numbers seem to be declining at around 1% each year. Swifts are not related to swallows but their lifestyle is similar. The decline in their case, at 7% annually, was the largest recorded during the survey. Given the onset of global warming in recent years, this is something of a surprise; swifts catch insects on the wing and there are usually more insects about in warm weather. According to Dick Coombes, pesticides may be to blame; these chemicals destroy the insects on which the swifts depend. The skylark is in trouble; its numbers continue to fall, although this marvellous singer was still present in 43% of the squares surveyed.

Some interesting regional variations were found. Song thrush numbers seem to be increasing in the east of the country but not elsewhere. This may be part of a more general trend; several species are faring better in the east and south of the country. Declines generally tended to be more apparent in the counties of the western seaboard between Clare and Donegal and also in Roscommon, Longford, Westmeath and Offaly.

A meaningful analysis could only be carried out for species which were recorded in 30 squares or more, so the survey does not assess the fortunes of our scarcest birds. Tree-sparrows were found in 14 squares, twites in only two and barn owls in one. Wood warblers and pied fly-catchers were seen in one square each. Ring ouzels were found in two. Some of our most vulnerable birds don’t even show up on this particular radar screen.

Just why these changes are taking place remains a mystery. With the very mild weather of the last few years, more birds may be surviving the winter. Changes in farming methods, and in land use generally, are bound to impact on bird numbers, while increased desertification in Africa may be depressing the numbers of migrants.

The Countryside Bird Survey is supported by the Wildlife Service and the Heritage Council.

Countryside Bird Survey Report 1998 — 2005 by R H Coombes, O Crowe, L Lysaght, J O’Halloran, O O’Sullivan, H J Wilson BirdWatch Ireland.