The Department of Energy and Environmental Protection (DEEP) and the Connecticut Audubon Society worked together July 9 to carefully remove newly hatched purple martins from their nests at the Connecticut Audubon Coastal Center at Milford Point, record their approximate age, place tiny leg bands on them and then put them back into the nest from which they came.

The colored bands will help scientists track the purple martins once they leave this colony. Laurie Fortin, DEEP wildlife biologist, said in past years birds from this Milford location have been found living in New York, Massachusetts, Rhode Island and even New Hampshire.

Several years ago the purple martin, Progne subis, was on the state's threatened species list, and while the bird is still a species of special concern in Connecticut, it continues to rebound, according to Tom Andersen, director of communications for the Connecticut Audubon Society.

“There are more than 170 baby birds in the nests this summer,” Andersen said about the Milford colony. “Last year we banded 128, in 2017 we banded 107, and in 2016 we banded 93. It's an amazingly positive conservation trend.”

Tuesday’s banding effort in Milford was part of an annual DEEP effort to accumulate data about habits and whereabouts of birds from purple martin colonies around the state, including those at Hammonasset State Park’s East Beach Nature Center in Madison, and Sherwood Island State Park in Westport. Holding one small purple martin on Tuesday, DEEP wildlife biologist Shannon Kearney estimated its age based on its feathering, and that information was logged onto a sheet with other data.

For people like Patrick Comins, Connecticut Audubon's executive director, Tuesday’s banding was a field day as he listened to the songbirds. He described their vocalizations as “amazing and complex” and speculated as to the messages they were sending one another. He watched in awe as the purple martins carried butterflies and dragonflies to the young in their nests.

These large swallows, which only eat insects that they catch while on the wing, are completely dependent on man-made nesting areas in Connecticut, Audubon officials said. The colony at Milford Point is one of the most successful. Comins and Andersen said there had been a smaller colony here before, and in 2015 Phil Donahue and Marlo Thomas donated their nests to the Audubon when they moved from Westport. Each year the Audubon tries to add several nests.

Fortin and Brian Hess, also a DEEP wildlife biologist, said there are about 20 large purple martin colonies like this one in the state, and any number of smaller colonies. The DEEP and volunteers each year tag the state’s newborn birds with different color bands to help track them over the years, to see where the young birds wind up as adults.

A second numbered band can provide more specific information about individual birds.

“Purple martins are beautiful, much-admired songbirds, and these popular swallows are sought after as backyard birds all across the U.S., particularly in the south and east,” Milan Bull, the Audubon’s senior director of science and conservation, wrote on the Connecticut Audubon website. “Colonial nesters, purple martins nest in man-made ‘apartment’ style bird houses or clusters of gourds hung on poles or ‘gourd trees’.”

The Milford colony is at the south edge of the Wheeler salt marsh. The birds usually arrive here around May and leave at the end of July or beginning of August to begin their migration south.

The Audubon maintains a live-streaming system at the Milford colony so people can get a closeup and real-time look at the purple martins, including video from inside one of the nests. Viewers can see them when they arrive, and watch their daily activity at ctaudubon.org/2017/06/purple-martin-cam/.