You don't need to be a birder to appreciate the peacefulness and majesty of this natural phenomenon.
A few lucky boaters were recently on the lower Connecticut River at just the right time. A flock of thousands of tree swallows enveloped the dusk sky overhead, swooping and swarming in unison as the onlookers gasped in awe. They captured this breathtaking footage of the passerines in action just before they landed to roost on nearby Goose Island for the night.
These iridescent blue-feathered birds with white bellies roost on Goose Island every year during the late summer and early fall months. As many as 300,000 birds flock at a time and can settle in under two minutes -- a spectacle that often causes the Connecticut Audubon Society's annual boat tours to sell out.
Tree swallows are abundant across their field and wetland breeding grounds in North America and form massive flocks for migrating, molting and roosting.