Popular Overwintering Spot for Ducks Loses Popularity Amid Climate Change

More than 75 percent of the birds that typically spend winter around the largest lake the United Kingdom, Lough Neagh, are overwintering elsewhere, according to researchers from Queen's University in Belfast, who cite climate change as at least part of the reason. 

The research, published in the journal Freshwater Biology, found that the number of diving ducks -- including tufted duck, goldeneye, pochard and scaup -- migrating to Lough Neagh for the winter months has dropped from 100,000 to nearly 20,000 in less than a decade.

Moreover, the researchers found that the number of snails and insects living at the bottom of the lake have also declined dramatically. This loss of food, coupled with global climate change, has drastically affected the the numbers of overwintering water birds on the lake, the researchers said.

"Our research found there was a 66 percent decline in the numbers of insects and snails in the lake and that this was associated with a decline of algae. As the water birds, which migrate from Northern and Eastern Europe to spend the winter months on the lake, depend on these invertebrates, we partly attribute their decline to the lack of food as well as the effects of climate change," said lead study author Irena Tománková, from Quercus, Northern Ireland's Center for Biodiversity and Conservation Science at Queen's University.

"Historically the lake was heavily affected by organic pollution as a result of nutrients from agricultural run-off. This artificially boosted its productivity. Now that conservation schemes are beginning to have an effect and reduce levels of pollution we are seeing increasing water quality and the unexpected consequence is fewer invertebrates and as a result less duck food."

Warming climate may be a factor in the migrating bird's avoidance of the lake, as the breeding grounds the birds use in northern Europe may not be getting as cold as they have in the past, according to a separate study published in Global Change Biology, which reported that winter temperatures in Northern Europe have increased by 3.8oC in the past 30 years, meaning that lakes that used to be frozen over in winter are now available for the birds to feed on.

The reason for the decline of overwintering birds on Lough Neagh could be as simple as the birds not needing to travel as far for food and warm temperatures, but it has resulted in Lough Neagh loosing some of its importance as a conservation area.

 "It is critically important for conservationists and policy makers to understand the reasons behind the dramatic changes that have been recorded at Lough Neagh," said Ian Enlander, from the Northern Ireland Environment Agency. "This work has been an outstanding contribution to improving our knowledge for this site. It underlines the need for international conservation measures to apply across the entire range of these migratory species."