The number of waterbirds spending the winter in Ireland has collapsed by 40% in just 20 years.
That's according to a new study by BirdWatch Ireland which found that over the past five years, the number of wintering waterbirds like ducks, geese, swans and wading birds had fallen by 15%.
However, since the mid-1990s, this number has fallen by almost 500,000 individual birds - a fall of 40%.
Ireland is an important wintering area for these birds which breed at Arctic latitudes and migrate southwards to spend the winter on estuaries, coastal bays, rivers and lakes.
The study found that wading bird species, including Knot, Dunlin, Golden Plover and Redshank, have been the worst hit, suffering a combined loss of more than 100,000 individuals (19%) over the past five years.
Wildfowl, including 14 species of duck, three species of swan and four species of geese, declined by 28,000 individuals (9%). In total, 27 species declined by over 10% over the course of the last five years, with only seven species managing to increase by more than 10%.
Lead author of the study and a member of BirdWatch Ireland's conservation team Brian Burke described the rate of decline as "alarming" and said that climate change was directly impacting the collapse in numbers.
"The declines we’re seeing in Ireland are consistent with the global pattern of declines.
According to figures published by BirdLife International in 2017, 17% of all waterbird species are considered globally threatened, which is extremely concerning.
"Numerous pressures can impact migratory birds on their breeding grounds, along their migration route, and at their wintering sites, and we know that climate change is playing a significant role," he said.
Mr Burke said that recent studies have shown that climate change is causing shifts in the migratory behaviour of many of familiar wintering waterbirds coming to Ireland with milder winters meaning that many species no longer have to migrate as far as Ireland in order to find ice-free wetlands.
In addition, climate change has made conditions on breeding grounds more difficult leading to poorer breeding success and a fall in population.
Problems at wetland sites here in Ireland are also likely to be affecting these species, including disturbance from increased recreational use of wetlands by people and unleashed dogs and loss of habitat due to changes in land use.
However, Mr Burke did point to a number of positives including increases in the number of Whooper Swans and Black-tailed Godwits. There are also 1,400 Little Egrets across the country – a species that wasn’t present in Ireland in 1994.
The waterbird population in Ireland is monitored through the Irish Wetland Bird Survey (I-WeBS) and coordinated by BirdWatch Ireland.