Common scoters have declined dramatically, for no apparent reason. But a charity's researchers may have hit on a way to help.
RSPB researchers investigating the puzzling case of the disappearing duck may finally have come up with a solution.
Ornithologists have been mystified – and alarmed – by the decline in breeding numbers of the now mis-named common scoter.
In the UK, this species now only breeds at a few locations in the Scottish Highlands, including the Flow Country of Caithness and Sutherland and at several lochs in Inverness-shire.
The bird – which has always been more common as a winter visitor - was formerly more widespread in northern Scotland and conservationists have been left puzzled as there is no shortage of suitable habitat for it.
This study highlights promising management options for restoring populations of this declining species
RSPB Scotland funded a three-year research project and the team at the charity’s Centre for Conservation Science now believes that a solution to the birds’ recovery might be found by restoring the balance between fish and invertebrates in common scoter habitat.
They say that, in some cases, angling could be one way to help restore the scoter population.
Dr Mark Hancock said: “Of all the lochs we investigated during this work, scoters bred most often at those with the shallowest water and the most large, freshwater invertebrates. It soon became clear that there were more insects where there were fewer brown trout, so it looks like scoters are being limited by a lack of food in places where the fish are eating it all.
“We're now using these results to design new ways of helping scoters. For example, in areas of the north Highlands where angling activity has dropped off and fish numbers have increased, more trout angling is potentially one way to boost freshwater insect life. At hydro lochs, where water levels are to some extent under human control, we could also aim to maximise the area of shallow water.”
The common scoter project was supported by Scottish Natural Heritage (SNH), the Wildfowl and Wetlands Trust (WWT) and The Conservation Volunteers.
Dr Andy Douse of SNH, a co-author of the study, said: "Scotland is the only part of the UK to have breeding scoters, many of which nest in legally-protected nature conservation sites. This study highlights promising management options for restoring populations of this declining species."
Hannah Robson of WWT, also a co-author, said: “Scoters are amazing birds: an arctic species finding a haven in remote Scottish lochs. This research points to the ways in which we might be able to save them as a fascinating part of our Scottish wildlife heritage.”