The dense food supplies to be found in the seas around Alaska are crucial not only for the eiders but many mammals like seals and several species of whales also which like the ducks come to this area in the winter to feed. In the same way that international flyways and the protection of passage for birds through these areas, the end points of birds movements for breeding and feeding are vital also.
As we speak, the vast flocks will have headed back towards the coast where they will imminently be starting to nest and breed but back in late March World on the Move reporter Jeff Wilson was lucky enough to be on board the US Coastguard vessel the Healey during its latest research survey to the Bering Sea. Amongst the 30 scientists on board studying everything that swims, float and flies in that area during the winter he caught up with Jim Lovvorn of the University of Wyoming who has been studying the biology and behaviour of these beautiful ducks.
"It was a long drawn out winter and slightly delayed spring for us it felt and yet the changes being seen in our climate is perhaps showing more signs of impact at the poles than anywhere else. The loss of ice cover earlier and earlier in some areas has major impacts on polar bears and other species that need stability and consistency in the areas they move across and feed from. The northern Bering Sea (a stretch of ocean between Alaska and Russia) supports rich amounts of benthic or bottom dwelling food – communities of fish, shellfish, worms, etc which are a vital food source for other larger marine mammals and birds which come to this area of the sea to overwinter and feed.
But with water temperatures warming in the northern Bering sea, the distribution and availability of these food items is changing and scientists need to find out what impacts this will have on those that rely on them as a food source as all these ecosystems and food chain interactions could be effected."
One migratory species that goes out to the Bering Sea to overwinter is a type of diving duck, the Spectacled Eider – they migrate from areas of coastal tundra where they nest and breed to moulting areas and to important feeding areas of the Bering sea. These ducks were only discovered to be overwintering in these vast flocks out in the ice in the 1970s. They settle in dense flocks out at sea, in polynyas or ice “leads” as they are called which are an area of open water surrounded by sea ice, formed by ocean currents.
The ducks dive down into the freezing waters to feed on the rich supply of crustaceans, and shellfish below. Braving howling artic winds as the ship noisily forced its way through the ice, Jeff attempted to find a quiet corner away from the throb of the ships engines in which to interview Jim Lovvorn from the Department of Zoology at the University of Wyoming who has been studying the links between the food below and the spectacled eiders above the ice… but there’s nowhere quiet on an icebreaker as you can hear in the audio clip above.