entry smap 290: common eider's swimming abilities

common eiders are designed for a life in the sea, specifically the cold northern oceans. they have several special adaptations to survive the cold but here i will mention some of their abilities as swimmers both on the surface and under or as they say in India, inside the water. with their legs set far back on their body and big webbed feet they are powerful swimmers that can deal with the at times rough ocean. in the photo above their bow wave and wake are clearly visible, much like one created by a boat.

i was standing on the footbridge as a juvenile male swam toward a group on the other side of the bridge. these sea ducks are heavy with dense bones that help make them particularly good divers. but this feature also disadvantages them when taking flight so instead of making the great effort of rising up and running across the water's surface in order to take off they generally prefer to swim.

since they are so heavy they sit low in the water which is why they create a more distinct bow wave than many other ducks. rather than gliding lightly over the surface they have to push the water in front of them away to the sides. their powerful legs do the pushing leaving visible roiled water behind. they manage fine even in choppy waters, though then of course their wake is far less visible

to dive they jump up and forward and dive head first. to help propel themselves under they partially open their wings and pump in order to fly as much as swim, using both their wings and feet. also this allows them to reach the bottom where they feed on mussels and other invertebrates. they steer using their feet as rudders.

to stay underwater they must continually fight against their buoyancy but when they want to return to the surface they just stop swimming and let themselves naturally float upward. when reaching the surface they pop up slightly above the water much like a ball released below the surface does.

when needed they can swim much faster over short distances by lifting themselves higher up in the water and pumping their legs very quickly. they can often be seen doing this to catch up to their group or when they sense danger.

although there are an unusual number of juvenile eider here locally there has been an alarming reduction of eider populations several places along the northern coasts in Norway.