Baby bird boom: Purple martin banding project reveals growing numbers at HCT’s Cold Brook Preserve

“Build it and they will come,” said Al Curtis, longtime Harwich Conservation Trust (HCT) volunteer. And despite the recent resurgence of the Red Sox, Curtis wasn’t talking baseball–it was all about purple martins!

A fledgling purple martin receives a band at the Robert F. Smith Cold Brook Preserve. Photo by Gerry Beetham

The beautiful birds have become feathered celebrities at the Robert F. Smith Cold Brook Preserve since they moved into a cool-looking gourd rack that was installed last year, thanks to generous HCT donors. The rack holds tubby white bird homes that can be raised and lowered, a modern twist on traditional martin housing.

This week, purple martin science took center stage, when fledgling martins were banded by master bird bander Sue Finnegan and a team of avian enthusiasts. It was the second year of the banding program, and the numbers show that the gourd rack is growing in popularity.

Last year, four fledglings were banded, a great start considering that the gourd rack had just been installed. But a population boom is underway. “This year, we had 17,” said Curtis.

Benefits of bird banding

Bird banding provides a wealth of valuable information. The Purple Martin Conservation Association explains it this way: “Nearly everything humans have learned about the migrations, movements, and longevity of birds has come from organized banding programs.”

“Each band has its own number, just like a Social Security number,” Finnegan told HCT last year. “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.

Curtis has been birding at Cold Brook for more than 20 years, and he’s a big fan of HCT’s recent rewilding project at the Preserve, which added a half-mile All Persons Trail, restored 44 acres of wetland and a mile of stream habitat. Now home to all kinds of wildlife and flourishing native plants, the area has become a popular hiking and nature-watching destination.

The gourd rack’s design allows the gourds to be lowered and removed easily. Photo by Gerry Beetham

‘Fantastic’ restoration at Cold Brook

“This restoration was fantastic,” said Curtis. “Every time I go over there, I just marvel at how everything has changed from what it used to be.”

Part of that change was the arrival of the purple martins, sporting their iridescent sheen, with a luminous color that can appear as dark purple, green or navy blue, depending on the viewing angle.

“I had never seen a purple martin there before, but the fact that we put up those racks last year and immediately got takers is exciting,” said Curtis.

The intriguing look of the gourd rack and the white gourds has led Curtis into some amusing conversations with trail users. “I was over there monitoring the racks and keeping an eye on the eggs, and someone asked me if they were for Wi-Fi. Someone else asked me if they were trail cameras.”

But housing like the Cold Brook gourd rack 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.”

So the next time you’re over at Cold Brook, spend a moment near the gourd rack and watch the purple martins in action. They’ll be zipping through the sky, eating insects on the fly, then heading back to their spiffy new homes, where the next generation is growing up.

Photo gallery: HCT volunteer photographer Gerry Beetham captured these great images of the bird banding expedition at the Cold Brook Preserve:

—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.