Winter Waterbirds are Returning

As land birds migrate in Fall and Spring, so do the water birds.  And as do the land birds, waterbirds migrate at different times within these two seasons.

Have you noticed fewer cormorants from what we saw last summer? The Double-crested Cormorants (DCCOs) with bright orangish-red faces that nested on Ram Island (DCCOs also nest on 80 other Maine islands) are heading south for the winter.

But wait – we still see cormorants here. Along with the straggling DCCOs that are still migrating from sites north of here there is another species - the Great Cormorants (GRCOs) with white faces and a big white spot on their flanks.

Let’s say that there is a cormorant ‘changing of the guard’ – with a bit of overlap. The DCCOs breed here in the summer and in the fall migrate south for the winter. The GRCOs breed north of here both in Maine and Canada and move southerly for the winter. Why do they stay here in Maine for a cold and icy winter perched on Cushing Island’s northeasterly-facing cliffs overlooking Whitehead Passage? 

Each year they return to face the northeasterly storms. Their numbers appear to be increasing slightly from about 15 several years ago to nearly 25 counted last winter. However, there is a decline in Maine’s breeding population due to predation of the Bald Eagle on nestlings. As of 2018 only 38 pairs nested on a couple of islands near Isle au Haut. (3)

Are these wintering Cushing Island GRCOs from these small Maine breeding populations or have they migrated from the northern Nova Scotia to Newfoundland where there are larger breeding populations? Apparently, there are larger non-breeding populations of these cormorants wintering at Biddeford Pool, Dyer Point, and Schoodic Point - suggesting they are from further north than Maine? (3)

Either way, it is nice to have cormorants here for the winter, even though it is with great concern as each winter storm blows through this area.

Female and Male

Common Eiders are partial migrants – they move from short- to medium-distances. Our female Common Eiders appear to be around the island year-round, although there may be local movements along the coast, from time to time. The males, however, leave (molt-migration) the ladies as they begin their egg incubation in April. Females (breeders) are also known to migrate to molt sites in late August and September. However, the female and immature eiders along the backshore have consistently numbered around 150-200 from late summer to present (frequently seen off Seashore and Alderbrook/Onway and the South Shore - near the culvert). The males return in late Fall and Winter. We see one today, October 13, with the female and immature eiders.

Where do the males go in the summer and why? They go to safe harbors where they molt their flight feathers, leaving them flightless and vulnerable to predators. Where are these safe harbors? Some northern movement has been documented (4) or they may stay close to general area of breeding. In the 1970s there were significant numbers of these male eiders off Mt. Desert Island. One ornithologist hypothesized that the male eiders undergo molt migration to the Gulf of St. Lawerence using an overland route. This migration route has been supported by observations from central Maine such as the Moosehead Lake Region. (3)

Common Loon - Winter Plumage

Credit (Ashok Khosia): https://www.seeingbirds.com/Birds-by-Family/Loons/Common-Loon-1/i-BQJwjZ9/A

The Common Loons are returning from the lakes west of here. Several can be seen on the ferry ride from Peaks Island to Portland. They will soon gather in Hussey Sound where they congregate in the late afternoon – perhaps for night of rest – though we find ourselves asking if "rest" is really possible with the strong currents and winds rushing through this opening into Casco Bay? One loon is already seen in the cove at the end of Great Pond Road – is it the same loon that spent last winter there patroling the cove, chasing off (bullying?) any competitors for food - such as the pocket-size, Red-breasted Merganser? (Please see previous blog on the Common Loon: May 2024 Looney for Loons...)

Today October 13, seven mergansers (either the Common or Red-breasted) were seen flying along the backshore. Both merganser species have a white patch on the inner wing – the Common Merganser’s white patch is larger. Common Mergansers breed in Maine’s lakes and further into Canadian provinces. The Red-breasted Mergansers breeding areas include Maine’s Down East and Maritime Canada. (2)

Even though it is sad to see our summer residents leave Peaks Island, it is a thrill to see the beginning of the return of our winter waterbirds – loons, scoters, male eiders, Buffleheads, mergansers, goldeneyes, Long-tailed Ducks, grebes, and possibly the more occasional visitor – the Harlequin Duck will arrive soon. Let’s not forget about our year-round diminutive Black Guillemot that breeds on Outer Green Island, Whitehead Cliffs, and possibly Ram Island.

Black Guillemot - Winter Plumage

And we still have some gulls either passing-by (Ring-billed Gulls) or staying for the winter (Herring Gulls and perhaps a few Black-backed Gulls).

References:

1. Baldassarre, G. 2014. Ducks, Geese, and Swans of North America. Vol. 2. Johns Hopkins University Press.

2. Behrens, K. and Cox, C. 2013. Peterson Reference Guide to Seawatching. Eastern Waterbirds in Flight. Houghton Mifflin Harcourt Publishing.

3. Vickery, P.D. 2020. Birds of Maine. Princeton University Press. Note specific references within: (Brad Allen 2012)

4. Birds of the World. Cornell Lab of Ornithology. Online database. Note specific reference within: ( Palmer 1976)

Footnote 1:

Great Cormorants:

The breeding population in Maine is considered ‘Threatened’.  (‘Priority 1 Species of Greatest Conservation Need’ in Maine’s 2015 Wildlife Action Plan.)

Footnote 2:

Scientific Names:

Double-crested Cormorant – Phalacrocorax auritus

“Diving piscivore whose wing-drying stance is an iconic sight on Maine waters” (3)

Great Cormorant – Phalacrocorax carbo

“ A cormorant with a global range, but a rocky history and uncertain future in Maine” (3)

Common Eider - Somateria mollissima dresseri

“This familiar, year-round Maine coastal diving duck may be in trouble” (3)

Common Loon – Gavia immer

“An iconic diving bird that haunts Maine’s lakes in summer” (#)

Photos and by: Patty Wainright

Reviewers: Sam Wainright, Michelle Brown, Valerie Kelly, Marty, Michael LaCombe