Sep 04 2012
The other day at Acadia National Park I watched a female common eider (Somateria mollissima) climb up on a boulder and eat the barnacles. At one point she opened her wings and I saw they were surprisingly short.
Since eiders are the largest duck in the northern hemisphere they need substantial wings to fly but this bird’s wings weren’t long enough to carry her. Was she crippled? No, she was molting.
Like many ducks and geese, common eiders completely molt their tail and wing feathers in late summer after the breeding season. This means they can’t fly for 3-4 weeks.
This isn’t a terrible hardship for an eider because swimming is their most important skill. It’s how they get their food (marine crustaceans) and how they avoid predators.
Eiders aren’t the only ones who go through a flightless period every year. Canada geese do, too, but I’ve never noticed it. They hide it well.
It’s taken me a long time to realize that I’ve never seen a common eider fly. I only visit their habitat when they’re flightless.
(photo by Stuart Burns via Wikimedia Commons. Click on the photo to see the original)