"Birds of Casco Bay" with Seacoast Tours Trip Report

Our first ever “Birds of Casco Bay” in partnership with Freeport’s own Seacoast Tours featured a rewarding escape from the heat on a sultry early summer day on June 6th, 2021. With temperatures rapidly rising to near 90-degrees, we were sure glad to be offshore enjoying a light but refreshing breeze.

We motored around several of the islands between Freeport and Harpswell, checking ledges and outer islands for various bird- and wildlife. Harbor Seals were numerous, and we spotted a couple of Harbor Porpoise. All the expected local breeding birds were seen well, including numerous Ospreys, two Bald Eagles at their nests, lots of Common Eiders, Herring Gulls, Great Black-backed Gulls, and Double-crested Cormorants. Common Terns were, well, common, and we spotted several Great Blue Herons, two oversummering Common Loons, and heard and saw several Song Sparrows singing from sparsely vegetated, treeless islands.

The only shorebird that breeds in the bay are Spotted Sandpipers, and we spotted a few Spotties. We also checked carefully for roosting migrant shorebirds and found some on Upper Green Island: 8 Ruddy Turnstones and 11 Short-billed Dowitchers. A couple of first summer Bonaparte’s Gulls were expected, but a Roseate Tern – well up the bay almost to the mouth of Middle Bay – was much less expected. Could this be a bird that breeds on Outer Green Island or has it ventured all the way up from the big colony on Stratton Island off of Prout’s Neck.

I can’t recall seeing a Roseate this far into the northwest corner of Casco Bay, but bird-of-the-day honors goes to the third-cycle LESSER BLACK-BACKED GULL that was loafing on French Island Ledge. Rare anywhere in Maine in the summer, it is even rarer in Casco Bay (photo above).

With a few noteworthy observations and good views of some of our regular residents, we definitely saw the potential for further birding exploration of these rarely-if-ever birded Casco Bay islands.