Bird populations fared well over past decade but some species suffered, survey finds
IRELAND’S BIRDS have fared well over the past decade, with many species showing population increases, according to a major new study.
However, the Countryside Bird Survey expresses concern about the dwindling numbers of kestrels, skylarks, swifts and mistle thrushes in the countryside.
Intensive agriculture practice, the increased use of fertiliser and pesticides, a switch from tillage to pasture and climate change have played a role in population declines, according to BirdWatch Ireland.
But milder winters have helped smaller species to prosper.
The swift population is falling by 8 per cent a year and the kestrel, once Ireland’s most common bird of prey, by 7 per cent, according to the survey.
“Overall, we’re surprised that so many species are doing so well, but you’d have to be concerned about the likes of the kestrel and the skylark,” said BirdWatch Ireland co-ordinator Dick Coombes.
None of the rarer species recorded in the survey was in danger of extinction, he said, though some other species might be “slipping below the radar”.
It is believed the 1970s and 1980s saw big falls in many bird populations, though no comprehensive research was carried out at the time.
The research covers a 10-year period from 1998 to 2007 and was carried out by BirdWatch Ireland and the National Parks and Wildlife Service.
More than 500 volunteers turned out as early as 6am each spring to measure bird populations in almost 400 separate areas of the country.
Some 145 species were recorded, of which 62 were found in 20 or more areas. The wren, robin, blackbird and chaffinch were the most widespread, being found in 90 per cent of areas, while the rook, starling and wren were the most abundant.
According to an analysis of 57 of the most widespread species, 25 showed an increase in population over the 10 years, nine declined and 23 remained stable.
Pigeons, warblers, finches and buntings generally fared well, with the greatest population increases observed among the stonechat, blackcap, spotted flycatcher, goldfinch, redpoll and bullfinch.
Most species listed as of conservation concern in Ireland have remained stable or shown an increase during the period, the report says. “It is pleasing to see that more recent declines have been relatively few, and were well outnumbers by species with increasing trends.”
The decline in kestrel, skylark and mistle thrush is thought to be caused by changes in agricultural practice. A fall in the swift population is attributed to rainfall patterns in north Africa and, possibly, pesticides and a shortage of nest sites linked to modern building practices.
The report says declines in the robin and magpie are hard to explain.
Some regional variations were observed. The swallow increased in the southwest and declined in the midlands, while the song thrush increased in the northeast and declined in the southeast. The decline in skylark numbers is driven by declines in the west.
Irish trends appear to mirror those in the rest of Europe, where massive declines in bird populations during the 1970s and 1980s seem to have abated.
The last Irish countryside bird to go completely extinct was the corn bunting in the 1980s.
With a 12th season of monitoring due to start shortly, BirdWatch Ireland says volunteers with good bird identification skills are welcome to participate in the research.
Biodiversity in the Irish countryside has greatly diminished as a result of changing farming practices, according to a study conducted by UCD scientists on behalf of the Environmental Protection Agency (EPA).
The abundance and diversity of bees, birds and other species of insects and plants have suffered serious losses, the five-year Ag-Biota project found.
The study says the increased use of machinery, the removal of hedgerows, and the greater use of chemicals has led to landscape simplification and degradation and a reduction in the diversity of species.
Bumblebee numbers and the diversity of bumblebee species on moderately to intensively managed farmland may have declined by up to 50 per cent over the past 20-30 years, according to Dr Gordon Purvis of UCD’s school of biology and environmental science.
A marked decline in the diversity of bird species has been noted in areas where the ecological quality of the hedgerows has declined due to the intensification of farming, Dr Purvis said.
EPA director Larry Stapleton said the report showed there were key agronomic benefits to be gained from maintaining and enhancing diversity in the Irish countryside, such as the decomposition and recycling of nutrients and natural pest control. The final results of the project were presented to scientists, policymakers at a conference in Dublin yesterday.