Every morning from April to August, Mary Keleher puts her hair up in a ponytail and heads out to a Mashpee golf course, where she uses a rope-and-pulley system to lower white plastic gourds from trees. Inside each gourd is a nesting pair of birds.
“They are a little antsy today. They fly off, they circle around, fly past the gourds a few times, and they come back and land,” Keleher said.
Keleher first got involved with Purple Martins in 2007, when she discovered a half-dozen pairs breeding in an old, beaten-up bird house.
Since then, she’s almost single-handedly grown the local population of Purple Martins from those original six pairs to 96 pairs. Across different sites, these pairs hatched more than 200 chicks last year, nearly all of which left the nest safely.
“She's really sort of the mother of Purple Martins on Cape Cod,” said Mark Faherty, wildlife biologist at the Wellfleet Bay Wildlife Sanctuary and host of WCAI’s Weekly Bird Report. “Now there's just hundreds of these things throughout the Upper Cape.”
Purple Martins lived all across southern New England throughout the 1800s, but a severe cold and wet spell in 1903 decimated the population, and they all but disappeared from Cape Cod.
Now, when Faherty thinks of modern Purple Martins, a few things come to mind.
“Just gorgeous, gorgeous birds,” he said, adding, “They’re incredible flyers. They're really powerful, strong flyers.”
These boisterous, dark-winged birds have feathers on their heads and bellies that have the iridescent sheen of an oil slick. They migrate from the Amazon to the Northeast each spring.
Their sheer size and power compared to other swallows led Faherty to describe them as “tigers of the sky.” After a pause, he laughed. “I just made that up. I don't think anyone's ever called them that. But they’re eating other predators of the sky. They eat dragonflies, like big, big dragonflies, among other things.”
Finally, Faherty describes Purple Martins—at least in this part of the country—as deeply dependent.
“They're one of this small handful of species that have hitched their wagons to our shooting star. Us being humans,” he said. “Across basically one entire half of the country, they no longer nest in natural situations. They only nest in houses and gourds. And that's it. They’re not nesting in hollowed-out trees and swamps anymore.”
That’s where Mary Keleher, a 51-year-old secretary for the Mashpee Public Works Department, comes in.
“You know, once I started saying that I think Purple Martins could be all over Cape Cod, there was some feedback from some longtime birders that didn't think that they could do well here,” Keleher said.
“Some people were skeptical,” Faherty agreed. “Just because we have such cold wet springs, we were skeptical that Martins would take here. And apparently people tried in the ‘70s and ‘80s and they didn't really persist, the colonies.”
After Keleher started setting out gourds, she found it wasn’t necessarily the cold that bothers Purple Martins.
“They can keep themselves warm as long as they have the right housing. It's the lack of food,” she said.
As aerial insectivores, Purple Martins eat flying insects that sometimes don’t come out in bad weather.
“So if we have weather that’s rainy, windy, cold for several days, you know, four, five, six days, then that can be an issue,” she said. “They're not getting enough food. There could be a die-off.”
Over the years, these devastating events convinced Keleher and her teenage daughter Ashley to adopt a supplemental feeding system for the birds.
“I purchased crickets and I store them in my freezer,” she said. “If I have to do any type of supplemental feeding during bad weather I can just defrost the crickets, go out, fling them up in the air to [the Purple Martins] and they actually catch them and eat them.”
Keleher doesn’t know if the birds understand how devoted she is—coming out each day even in the rain and wind—but she says they do seem to recognize her.
“They spot me and they fly quite a distance over towards me,” she said. “And I'll have this cloud of Purple Martins flying around me as I'm walking out towards the gourds.”
Now, her success is undeniable: this year, Keleher and Faherty expect to see colonies overflowing in Falmouth, Cumaquid, Wellfleet, and beyond.
“It was a ‘If you build it, they will come’ situation,” Faherty said. “It just took somebody to take some initiative, put up some gourds, [and] have some faith that they will come.”
The biggest reward for Keleher will come in June, when the year’s first eggs start to hatch. Until then, she’ll keep going out each day to check on “her” birds.