I read a report about a king eider observed with a group of common eiders in the Cape Cod Canal. Two days in a row, the troops and I visited the canal, stopping at the Herring Run Visitors Recreation Center, Since the report stated that The king eider was around the mouth of the herring run. Both days, after arriving in the parking lot, I searched the canal with my binoculars and found a large raft of common eiders around the most of the herring run.
As we walked down toward the eiders, we had a chance of photographing common loon, red-breasted merganser, first-winter drake common goldeneye the first day and on the second day a pair of adult common goldeneye.
Most days, sweeping through the raft of common eiders with my binoculars I could not locate the king eider. However, the common eiders put up a great show. You could see them feeding, bathing, wing flapping, chasing other eiders, and listen to the eiders calling in their musical notes. Additionally, you were able to observe the multiple various plumages of the drake common eiders.
An interesting observation was watching the movement of the eiders as they swam and a rotary clockwise motion moved up the canal and slowly came back down the canal to the mouth of the herring run. The eiders were so busy with their activity that they did not pay any attention to us standing on the bank and photographing them but just continued on their routine business.