Thousands of crows in Lawrence are a marvel of nature and test case for new imaging technology [Video]

At a busy intersection near the Merrimack River in Lawrence, Craig Gibson set up his camera, peered through binoculars and got ready to witness a spectacle he’s seen hundreds of times.

This recent winter day presented a scene worthy of a Hitchcock movie, as thousands of crows started streaming in overhead from several directions, growing to a swarm estimated to be about 14 to 15,000 birds. As they do every night during the winter, the birds all headed for a stand of trees near the intersection of Marston, Prospect and Canal streets.

There are other big crow roosts around, including in Springfield and Hartford, Conn., but Lawrence has the largest roost in New England, Gibson explained.

And in addition to being a source of fascination for local bird watchers like Gibson, the Lawrence crow roost is now a test case for government-funded research on new 3D imaging technology.

Gibson recently …