Banding purple martins at Cold Brook: A labor of love and science

The purple martin saga at the Robert F. Smith Cold Brook Preserve is moving along as swiftly as the birds themselves. The fast-paced avian adventure arrived at the bird banding stage this week, a heartening development, and the latest wildlife success story at the popular Preserve that was transformed by a Harwich Conservation Trust (HCT) eco-restoration project.

It all started early this year when noted Cape birder Mary Keleher reached out to HCT, suggesting that a purple martin gourd rack would be a fantastic addition to Cold Brook. These gourd racks are specially designed to give purple martins the perfect Cape Cod home, and Keleher has been a pioneer in increasing the purple martin population on the Cape.

Human-made housing is essential for martins to thrive. According to the Massachusetts Division of Fisheries and Wildlife, “although Purple Martins can still be found using natural cavities in the western United States, in the east they are now dependent on human-maintained nesting structures like gourds or houses.”

A gourd rack rises

The gourd rack setup, which consists of a pole and six modern-looking artificial gourds, was about $700. Generous HCT donors flocked to the cause, and funds were raised. By February, the new gourd rack was in place, and the waiting game began. Would purple martins find a perch at Cold Brook?

It turns out that these beautiful birds are pretty savvy when it comes to real estate. They were quickly able to suss out the advantages of the Cold Brook gourds: no rent, no mortgage, new construction and a plentiful supply of delicious insects. Purple martins were soon kicking the tires at the gourd rack, a breeding pair moved in to raise their next generation, and babies recently hatched.

This development caught the attention of Keleher and legendary master bird bander Sue Finnegan. With the martin babies just a tad over two weeks old, a merry banding party set out this week at Cold Brook. Those of us who had never seen bird banding were astounded by the speed, precision and gentleness of the operation.

You may wonder why birds are banded in the first place. The Purple Martin Conservation Association explains it this way: “Perhaps the most valuable tool in the conservationist’s and ornithologist’s investigative arsenal is the technique of bird banding, which is the placing of a permanent, lightweight band on the leg of a bird for the purpose of individually identifying them in the future. Nearly everything humans have learned about the migrations, movements, and longevity of birds has come from organized banding programs.”

Strike up the band

A table was set up near the gourd rack, and noted birder Michele Burnat fired up a computer to record the data. Burnat is also known for her role with the Birdability organization that creates programs to share the joys of birding with folks who have disabilities and recently led a program at Cold Brook, taking advantage of the easy to navigate All Persons Trail.

The gourd rack offered a distinct advantage for bird banding: the gourds can be lowered to the ground using a pulley system similar to a flagpole. Then, a gourd could be easily detached and brought to the table, where Finnegan was ready to work her banding magic.

With incredible precision, speed and dexterity, Finnegan attached a tiny numbered band to the legs of four fledgling purple martins.

“Each band has its own number, just like a Social Security number,” she said. “So, if someone catches a bird in Costa Rica, they can check the band number and find out that it was banded at Cold Brook, for instance.” Data, including the bird’s location, age, weight and fat level and number is entered into a portal on the United States Geological Survey (USGS) Bird Banding Laboratory website.

Finnegan, who has been banding birds on the Cape for more than 25 years, said a Federal Bird Banding and Marking Permit is required to do the work. Getting that permit takes a lot of work and field experience. “It’s a rigorous standard,” she added. “There was a three-day oral test and a three-hour written test.”

Mary Keleher and purple martins: A love story

Keleher, who has raised purple martin awareness around Cape Cod and worked to get new gourd racks installed in different locations, was asked how she got mixed up with martins in the first place.

“It just happened,” said Keleher. “I was working on the state’s Breeding Bird Atlas and I found a couple of pairs of purple martins breeding in an old beat-up wooden box at the Willowbend Country Club, and I thought, I’ll put up new housing for them. It just took off after that. And I started to get more involved than I ever really thought I would.”

Such is the life of a passionate birder. “I just kind of fell in love with them,” said Keleher. When bad weather or days-long storms inhibit the ability of purple martins to feed on insects, she will distribute crickets, cicadas and even scrambled eggs, sometimes tossing them in the air so the birds can feed on the fly.

So, when you pass by the purple martin gourd rack at Cold Brook, take the time to notice these lovely birds with their trademark iridescent sheen. It’s also nice to know that some wonderful people are keeping a close eye on them.

—Sign up for HCT eNews, a great way to stay in the loop about exciting HCT events, guided walks and other interesting news.

—Your tax-deductible contributions help fulfill the mission of the Harwich Conservation Trust to preserve land that protects woods, water, wildlife and our shared quality of life. And your land-saving financial support helps us preserve beautiful properties that can become stellar trail destinations. Find out how to donate by clicking here.