Zack Klyver just emailed the following to be shared with Maine Birds.
On this mornings whale watch tour [from Bar Harbor] Laura Kennedy, (Seabird Biologist and grad student who is conducting seabird surveys from the boat) spotted a dark shearwater among a small group of Great sitting on the ocean. She asked me what I thought. When we got closer to it we both realized that it was not a sooty but rather much larger, heavier, and with a nearly white or off yellow bill that had all parts (nares, etc,) clearly outlined in black. I thought the bird was 1/2 or 2x bigger than the Great sitting nearby. A cursory look through books and the internet seems to suggest a Parkinson's(Procellaria parkinsoni) as it had no white chin and no pink bill. Our whale researcher (Jess McCordic) who was on the bridge with camera in hand captured great photos for us, but alas the camera is still on the boat.
Zack has enormous experience on the water so this promises to be something very interesting.
Best, Peter