Vermont Rare Bird Reports 2021

Jim Mead --
Clem Nilan -- not known

Cloudy, no precipitation, little wind. Conditions for lake observation were good, i.e. water surface was generally calm, no heat shimmer, no fog.

Spotting Scope: Kowa Prominar TSN-883 with 20-60X Zoom eyepiece.
Binoculars: Swarovski Swarovision 8.5 X 42.

I had no prior experience with this species nor Arctic Loon unlike my experiences with Common and Red-throated loons which are too many to recall.

Lake Champlain with open water (ice free) north of the bridge. Other loon species present at the time of observation included Common Loon (2) and Red-throated Loon (1). For complete species lists see eBird records: Champlain Bridge/Chimney Point
https://ebird.org/checklist/S78620516; DAR State Park https://ebird.org/checklist/S79201955; Owls Head Bay https://ebird.org/checklist/S78777088; Tri-Town Water District Plant/ Oven Bay https://ebird.org/checklist/S78777053.

On water and diving (feeding). Not observed in flight. Occasional standing wing flaps were observed.

None heard.

We determined that the subject loon was likely an adult in basic plumage. Being that it (PALO) and the Red-throated (RTLO) loon kept “company” with one another throughout much of the observation time, this provided opportunities to directly compare species’ similarities and differences. The PALO (3.7 lb.) was noticeably smaller with a head profile that was smoother, more rounded than that of the Common Loons (9 lb.) present at the Champlain Bridge location. Weights, as given by Sibley (2000), are used only to provide a relative size reference for the three similar species discussed here. The PALO and RTLO (3.1 lb.) were similar in size, although the PALO appeared slightly bulkier (thicker neck). Both PALO and RTLO had white fore necks and dark (blackish, dark gray) hind necks. When viewed from the side the RTLO showed more white on the fore neck than the hind neck; the opposite was the case for the PALO. Both loons’ necks showed a sharp, straight demarcation between the white and the dark. At one point the PALO did a standing flap revealing a slight chin strap. The RTLO had more white on the face with the eye mostly in a field of white; in contrast the eye of the PALO was in the dark. The backs of both the PALO and the RTLO were dark with that of the PALO appearing blacker than the RTLO. The bill of the PALO was finer than that of a COLO and was held at a horizontal level rather than angled upwards as is characteristic of RTLO.
The possibility that this bird might be an Arctic Loon was eliminated on the basis of extreme rarity of the species in the eastern U.S., larger size (5.8 lb.) than either PALO or RTLO, and absence of a prominent white flank patch that extends above white and dark straight water line interface.
At the end of our observation time at the Champlain Bridge location both the PALO and suspicious RTLO together gradually worked their way up the lake and were seen in the vicinity of a large concrete structure (blocky building) on the New York side. To get a better view of them we went to DAR State Park. There at the observation deck we were able find that building and both birds. From that vantage point we got better views of the RTLO and were able to confirm it as such. Both loons continued moving up the lake and so we headed to Owls Head Bay, where Clem and Jim have access permission from one of the camp owners. The concrete structure was visible from there and again both loons were found. At that time they were a bit north of the concrete structure but in front of a blue camp with a deck and red lattice. The loons kept going north so we headed to Tri-Town. From there we relocated the blue camp and the two loons. From there, we had our best look at the PALO's chin strap when it performed a standing wing flap while facing us.
The preceding entry is a composite of a write-up done by Jim Mead reflecting observations made by Jim, Clem and me and submitted to eBird, as well as additional details of my own.

See details provided under Verbal Narrative & Description of Observation above.

See details provided under Verbal Narrative & Description of Observation above.

See details provided under Verbal Narrative & Description of Observation above.

See details provided under Verbal Narrative & Description of Observation above.

See details provided under Verbal Narrative & Description of Observation above.

No details recorded or recalled.

See details provided under Verbal Narrative & Description of Observation above.

No details recorded or recalled.

See details provided under Verbal Narrative & Description of Observation above.

Subject loon was likely an adult in basic plumage. Sex undeterminable.