: Breeds. Major colonies active early Apr-late Jul on Little Duck Island, Egg Rock, and in small numbers on other islands and along the uninhabited peninsulas along the eastern shoreline of MDI and at Schoodic Point. They move Sep/Oct to late Mar/early Apr where they gather in the hundreds in shallow waters near their favorite prey, Blue Mussels. While they can be found almost anywhere around MDI and Schoodic during these months, in years the largest congregations have been in the . These gatherings almost certainly include migrants from other parts of the species' range.
There are sizable numbers of migrant Common Eider late Oct-early Nov with close to 1000 birds passing on days with a strong eider flight.
Miscellany: Wintering Common Eider were much more numerous 1970-1990 when hundreds to thousands could be found off the eastern side of MDI. Their subsequent decline is thought to have been the result of a similarly sharp decline in Blue Mussels, their favorite food.
Male eiders leave the breeding islands once their females begin incubation, moving in late May/early Jun to shallow offshore ledges with ample food. Here in sometimes sizable flocks they molt their flight feathers quickly, becoming flightless for a month or more, before moving back inshore in Sep to join the females and young.
Our Common Eiders are of the race dresseri. There is one Jan 7, 2020 record of the more northerly race borealis.
You can learn more about Common Eider and see images here.
Last Updated: September 27th, 2022