Somateria mollissima
Common Eiders are the largest North American duck species with the drake weighing up to 6 and a half pounds. The drake's head is white with a black cap and a greenish nape. It has a long sloping olive or yellowish colored bill with a gray tip. It has a white breast, black flanks and a black tail. The adult hen has a barred brown body and brown head with a gray bill. (source: Flyways.us)