New analysis charts fortunes of waterbirds in Ireland

Fifteen waterbird species have stable or increasing wintering populations in Ireland, but 20 species are declining – including six that have decreased by more than half since the mid-1990s.

They are the key findings from the latest Irish Wetland Bird Survey (I-WeBS), which monitors the fortunes of the country's wildfowl, waders and other waterbirds.

Every winter, hundreds of dedicated bird surveyors count the waterbirds in their localities as part of I-WeBS. The survey has been running since 1994, funded by the National Parks and Wildlife Service (NPWS) and co-ordinated by BirdWatch Ireland. A recent study examined the changes in 36 wintering waterbird species at 97 of the most closely monitored wetland sites, spanning 15 counties across Ireland.

Common Goldeneye is one of a number of diving duck to have decreased considerably (Noel Austin).

 The greatest declines were seen in diving duck species, namely Common Goldeneye, Common Pochard and Greater Scaup, which have dropped by 65-90% on average since the mid-1990s across the 97 sites analysed. Climate change and warming winter temperatures are undoubtedly one of the drivers of these declines, allowing these birds to spend the winter closer to their breeding grounds in northern Europe.

At a more local level in Ireland, loss of habitat, changes to water quality, increased disturbance on lakes and in estuaries, and poorly situated developments all worsen the situation, meaning fewer and fewer of these birds return each year.

Plovers have also suffered huge drops of more than half. Northern Lapwing, traditionally referred to as the 'Green Plover' or Pilibín and often considered Ireland's national bird, has declined by 64% since the mid-1990s. European Golden Plover, which feeds on grasslands in every county in Ireland in the winter, has declined by a similar amount, as has the coastal Grey Plover.

European Golden Plover is a less and less familiar sight across Ireland (Ian Dickey).

Ireland's breeding Eurasian Curlew population is well known to be teetering on the edge of extinction, with only around 100 pairs nesting in recent summers. The wintering population is much larger, though, as birds from northern Europe migrate to Ireland from late summer to early spring, but these birds face similar threats throughout their range. Wintering Eurasian Curlew have declined by 43% in Ireland since the mid-1990s.

John Kennedy of BirdWatch Ireland, who led the research, said: "We regularly do this sort of analysis at national level, providing a 'health check' to see how Ireland's wintering waterbirds are doing but now we're delving a bit deeper to see precisely where the problems are.

"Ireland's waterbirds are indicators of the health of the wetland environment they use. These are sites that we depend on too – for drinking water, flood relief, agriculture, tourism, aquaculture and industry. As is always the case with this sort of research, it has answered some questions but poses many more, and we'll be scrutinising these results in the months and years to come to decipher some patterns of change that might not be so immediately obvious."

There is some good news. Black-tailed Godwit has increased by 92% since annual monitoring began in 1994. Species such as Mute Swan, Little Grebe and Grey Heron, which breed on Irish lakes and rivers, are all stable or increasing in number. One of Ireland's more recent arrivals, Little Egret, has shown a steady and significant increase since it appeared in Ireland 20 years ago and is now widespread across the entire country.

Species with a mixed report card include Pale-bellied Brent Goose, which has increased overall but is now showing a recent decline. Numbers of Sanderling are 85% higher than they were when monitoring began, but have decreased by 24% in the last five years. Recent declines of this magnitude are cause for concern and there is a risk that longer term increases for some species could be quickly undone in a few short years.

After a long-term increase, Pale-bellied Brent Goose has shown a recent decline (Ian Dickey).

Dr Seán Kelly, waterbird ecologist at the NPWS who manages the I-WeBS contract, commented: "The Irish Wetland Bird Survey is an incredibly successful and valuable bird monitoring programme. The success of the programme is down to the hundreds of citizen scientists and NPWS and BirdWatch Ireland staff across Ireland who take part in the survey. The size, strength and extent of this bird monitoring community is simply fantastic, and I would like to thank every individual for their ongoing efforts.

"The survey has been running since 1994 so the resulting long term dataset allows us to robustly monitor environmental change as it manifests in and impacts upon bird populations. I really encourage everyone to take a look at the report and consider the findings, at a local and national level. The data gathered under this survey allows us to further understand how and where conservation management and policies can be improved."