Birds of Casco Bay Tour report, 10/20/23

After postponing the tour due to dense fog, we found ourselves heading out on a perfect fall day we boarded the boat for our last ride of the season with our partner Seacoast Tours of Freeport. Our goal was to get out as late in the season as possible (the boat comes out of the water on Tuesday!) to sample the arrival of wintering waterbirds and the final departures of our summer denizens, and the later date this year made for some interesting observations.

For the arrivals part, SURF SCOTERS were surprisingly common, with numerous small flocks easily tallying well over 100 birds. A newly arrived HORNED GREBE was glimpsed, 9 RED-BREASTED MERGANSERS were a sign of the progressing season, and the number of COMMON LOONS – including a few in still-prefect breeding plumage – is rapidly increasing as well.

But we’re not that far removed from the summer season, as evidenced by a late OSPREY and several hundred DOUBLE-CRESTED CORMORANTS including a large migrant and/or foraging flock that flew around us, splitting up as they rounded French Island and alighted on rocks and oyster farm floats.

Like last year, the number of lingering LAUGHING GULLS in this area continues to impress, even if we only had about 15-20 total today. By checking out several floating oyster aquaculture facilities and exposed rock ledges, we practiced additional gull identifcation, comparing the general shape and size to the hulking HERRING GULLS and a few (quite low, actually) massive GREAT BLACK-BACKED GULLS, with plenty of RING-BILLED GULLS to bridge the gap.

We paused for a stately BALD EAGLE, and took plenty of time to enjoy an impressive amount of loafing HARBOR SEALS, along with learning about the local islands, landmarks, and oyster aquaculture.