I had intended the “Note From The Field” posts to be about my work in the field. However, I will not be heading into the field for another month or so. My boyfriend just left for the field (Wapusk National Park just north of Churchill, Manitoba) last week and therefore his research is on my mind. Therefore, this post will be about his study species: The common eider.
Eiders are large sea ducks which belong to the genus Somateria. Tree different types of eiders currently exist: common eiders, king eiders, and the spectacled eider. There is also a sea duck named the Steller’s eider – however, this bird belongs to the genus Polysticta and therefore is not technically an eider. You may have heard of eiders when shopping for quilts or comforters as eider down is considered to be one of the warmest and lightest downs available. However, eiderdown is becoming less common as farm-raised geese down and synthetic fills are more and more being used in blankets and quilts.
The common eider (Somateria mollissima) is the most numerous of the eider species and is also the largest duck in North America; ranging in size from about 50 to 70 centimeters and 1200 to 3000 grams. Male common eiders have very distinct, brilliant black and white markings (they sort of remind me of a soccer ball). The females, as with most bird species are fairly drab; browns overall with some back barring on their wings. Both males and females have a very distinctive wedge-shaped, sloping bill. Eiders have a very distinct and relaxing (and slightly human-like) “ah-ooo” call.
Overall, common eiders are circumpolar in range. In North America, the common eider can be found during the breeding season on coasts from Alaska, to Hudson Bay and James Bay around the Canadian coast to the Northern coast of Maine. Being coastal birds, common eiders feed on the water; diving to depths of up to 20 meters in order to feed on mollusks which make up the bulk of their diet. Overall, the common eider species is not threatened or endangered, however – some populations have seen localized decline. There are four races of common eiders in North America: a southern race (Somateria mollissima dresseri), a northern race (Somateria mollissima borealis) , a Pacific race (omateria mollissima v-nigra), and the Hudson Bay race (Somateria mollissima sedentaria). Dave studies the Hudson Bay race which remains all year within the Hudson Bay.
Eiders breed in colonies and nest on the ground with clutch sizes averaging from 3 to 5 eggs. Non-breeding females will also be found in a nesting colony and will help breeding females to protect young eiders from predators. Once a nest has been established and eggs have been laid, females rarely leave the nest, usually only to drink (and never to eat). Unless of course a pesky researcher flushes the female in order to study nest success.
Photos of real eiders from Wikimedia commons.
Wikipedia entry for “Eider”: http://en.wikipedia.org/wiki/Eider
Wikipedia entry for “Common Eider”: http://en.wikipedia.org/wiki/Common_Eider
Ducks Unlimited Canada: http://wetlandsfortomorrow.ducks.ca/lwcelder#Status
Ducks Unlimited United States: http://www.ducks.org/hunting/waterfowl-id/common-eider
The Cornell Lab of Ornithology: http://www.allaboutbirds.org/guide/Common_Eider/lifehistory
FYI: There was no complete Tree of Life entry for the common eider. Sad.