Southampton resident David Sagman said he saw the cloud in the distance during a routine birdwatching expedition Thursday, while standing at the end of Old Town Road in Southampton and overlooking the ocean.
"It seemed to be moving very slowly westward and northward with very subtle shape change," Sagman said.
"And no fishing boats were observed nearby."
The cloud was several miles offshore, he said, and he got the best photos he could, using an 800mm digiscope — a telescope for taking photos — on a tripod.
"I wondered if it could be composed of thousands of birds but other thoughts are welcome," Sagman said.