Charlie persisted and soon found the Sandwich Tern out in the open on the outermost bar, just past the edge of a large group of Common Terns. He said:
The tern was distinctly bigger than the Commons. It had black legs and a black bill with a pale yellowish tip. However, the shaggy feathering at the back of the crown was not visible. Also, the crown was mostly black, with only the foremost 1/3 of the crown having turned white. At this time of the year, I would have thought that the entire crown should have been white with black, shaggy feathering being present only at the extreme rear of the crown. When the bird bent forward to preen, some shaggy feathering could be seen at the rear of the crown, but none was visible when the bird held it's head up.
At the distance he was from the bird the only viable photography option was digiscoping (holding a camera up to a spotting scope, finding the image, and snapping a shot). This is an extremely tricky endeavor at best, from actually getting any image to appear to focusing the scope just right, sometimes with strong winds blowing, and not being able to do much at all about the light. Nevertheless, Charlie got a shot that clinches the identification, and that is all one can hope for in such a situation. It is the farthest tern in the photo.
If you right-click on the photo and view the file full-size the tern will show up much larger. However, here are two cropped and edited versions, altering the light and saturation which allows us to better see the bird and the yellow tip of the large bill, a definitive field mark for the species.
A moment after he took this photo the terns were spooked off the bar. Charlie lost it among the hundreds of individuals flying about, and it was not relocated. This is why everyone should try to have a camera with them at all times while out surveying, even if it is only one on a smartphone (and these have improved a great deal). At least this great bird did not elude us entirely - thanks Charlie!
Audubon Alliance for Coastal Waterbirds, Audubon Connecticut and the Connecticut Audubon Society partnering to improve conditions for coastal waterbirds in Connecticut.