Meet the Conservationist Saving New England’s Swallows, One Nest at a Time

On a June Sunday morning in Rowe, Massachusetts, the local library’s spare chairs fill quickly for a talk about swallows. It’s aptly timed: Lately, a community debate has erupted over the fate of Cliff Swallows nesting under the eaves of the nearby town hall. The mood feels uncertain, full of the nervous charge that often comes before opinions collide. But when Mara Silver begins to speak, the tone shifts. The room is clearly with the birds—and with the woman who has made it her life’s work to save them.

Wiry and soft-spoken, Silver has been inventing ways to help swallows survive for more than 30 years. The now-threatened colony across the road, home to nearly 20 percent of Massachusetts’s remaining Cliff Swallows, may be her greatest achievement—a living example of her belief that people can choose to make space for struggling species. Silver has helped grow the population there from a handful of nesting pairs to a peak of 45, by way of her hand-crafted ceramic nests and her ardent advocacy for sharing our buildings with other creatures.

“There are big things we can’t control—climate change, pesticide use, global insect declines,” Silver says. “But we can help at the nesting-site level. That’s where individuals can make a difference.”

Across North America, aerial insectivores such as swallows, swifts, and nightjars have seen some of the steepest declines among bird groups. Large colonies of Cliff Swallows still swirl in midwestern skies, yet the species is struggling in the Northeast. Meanwhile, Barn Swallows have declined across much of their range, their numbers dropping by nearly 40 percent since the 1960s.

The reasons are layered. Pesticides and a changing climate, for example, can reduce insect prey. But swallows in particular face threats because they’ve adapted to living near humans. Genetic research suggests that Barn Swallows may have co-evolved with human villages and farmsteads, and Cliff Swallows, once anchored to natural surfaces, now overwhelmingly nest beneath bridges or on buildings. Today, fresh coats of modern, glossy paint may be making once-reliable ledges too slick for swallows’ mud nests. Many of New England’s old wooden barns with open windows and doors have fallen or been replaced by sealed metal structures, which are cheaper and easier to maintain.

Making swallows feel at home

Silver began noticing these challenges firsthand in the early 1990s when she discovered Cliff Swallows nesting under the eaves of her apartment building. She watched as nearly all the nests were taken over by non-native House Sparrows or eventually fell, sending chicks tumbling to the ground. The experience sparked her curiosity and her compassion—and, in barns across western Massachusetts, she started to experiment with ways to help swallows stick.

Drawing on her undergraduate ceramics training, Silver sculpted and fired clay cups that could be fastened to rafters and under eaves. At one early site, she put up 150 ceramic nests on the exterior of a barn and found that Cliff Swallows quickly claimed the sturdy bases, reinforcing them with mud and raising chicks in nests that no longer fell down. Over two years, the colony grew from six pairs to more than 60. The experiment fused art and ecology and launched a singular career: part potter, part ornithologist, part evangelist for coexistence.

Since then, Silver has assembled a conservation toolkit that blends craft and biology. She attaches artificial nests and “nest starters” beneath eaves and bridges and creates mud puddles in spring so birds can gather building material. When necessary, she culls House Sparrows, the aggressive non-native invaders that seize swallow nests and sometimes kill the chicks inside.

In 2022, she formalized her effort by founding Swallow Conservation, a shoestring nonprofit that is spreading these methods across the Northeast. Farmers order her kiln-fired cups online, towns and land trusts bring her in to stabilize colonies, and schools invite her to talk to children about welcoming swallows to their communities.

Silver’s work covers most of the known Cliff Swallow colonies in Massachusetts along with a range of Barn Swallow sites. Before nesting season, Silver installs artificial nests, then spends around 30 hours per week driving around to monitor pairs throughout the season. Once the swallows move out, she removes and cleans the unoccupied nests to reduce infestations of parasites.

“She’s single-handedly doing almost all the swallow conservation in the Northeast, on her own time and on her own dime,” says Charles Brown, a behavioral ecologist at the University of Tulsa who has studied Cliff Swallows for more than four decades. “She's just a tremendous resource in that part of the world where these birds need her. It’s such a wonderful case study of the difference one person can make.”

Silver’s interventions are not just intuitive; they’re proven. In a study she co-authored with Brown and conservation biologist Linda Merry of Berkshire Community College (both frequent collaborators), the researchers found that colonies with clay cups, mud provisioning, and sparrow control stabilized or grew, bucking the regional trend.

The irony is that swallows have become vulnerable precisely because they adapted to human building patterns. “They’ve come to depend on our hospitality,” Silver says. “Close a barn window, and you can wipe out a colony.”

She emphasizes that people can make small, practical changes to support swallows: Keep doors and windows open and ledges accessible during nesting, avoid slick paints, and provide mud in spring. The kiln-fired cups—more durable than mud and placed where birds already try to build—become reliable homes that swallows accept quickly. Once they do, they return, generation after generation.

The challenge of coexistence

Among Silver’s most visible triumphs is Rowe Town Hall. She began monitoring the site more than nine years ago, after residents noticed six to eight nests clinging to the eaves. When a fresh paint job turned the trim too slick for mud nests, the colony faltered. In 2018, at the invitation of a town official, she installed ceramic cups along favored ledges. The effect was immediate. By 2024, 45 occupied nests ringed the building, making Rowe the largest Cliff Swallow stronghold in Massachusetts and, for many, a point of local pride.

But not everyone was won over. At least one municipal employee grumbled about droppings on window screens and birds swooping over workers’ heads. The Selectboard—the New England version of a town council—started voicing concerns about the colony, including Board of Health chair Herb Butzke, who says droppings contain “a long list of potential disease-causing organisms.”

Silver and Brown say the risks are overstated. “There’s not a single documented case of anyone catching something from swallow droppings,” Brown notes. Silver adds that the birds’ dives aren’t aggression but precision—adults folding their wings to slip through nest openings and hunt insects. Yet in June 2025, the Selectboard barred her from reinstalling the nests for the upcoming nesting season.

Officials suggested relocating the colony to a nearby building, but Silver explains that it’s not so simple: Swallows, not people, choose where they nest. “They’re flying here all the way from Argentina, from Paraguay,” she says. “They’ve imprinted on this site since the 1980s. If Rowe excludes them, we’re another step closer to losing Cliff Swallows as a nesting species in Massachusetts.”

Now, she and Brown are exploring a freestanding nesting structure that might attract the birds. Experimental platforms in Colorado and Quebec have shown some promise, but Silver’s own test frames in western Massachusetts have so far drawn no takers.

Beneath the local dispute runs a broader divide. Pest-control companies that sell nest removal services can amplify fears about swooping birds. But Silver points out there are ways to compromise—exterior awnings to shield doorways, scheduled cleanings funded by conservation groups, small design tweaks that keep people and birds out of each other’s way. The birds also offer their own form of free pest control: Each swallow consumes hundreds of insects a day, a benefit often overlooked in the conversation about mess and risk.

After the library talk, Silver leads a small crowd across Main Street. We step around goose droppings on the pondside lawn—no one is proposing to evict the geese—and tilt our faces to the eaves of the town hall.

The building looks animate. Birds stream in and out of their nests, wings snapping, chattering as they trade turns. They dive steeply, fold their wings, and vanish into the mud-and-clay chambers, only to rocket out seconds later. The air vibrates with motion, an exuberant choreography of speed and sound. It’s a reminder of the perspective at the heart of Silver’s work: that the structures we build are not separate from nature, but part of it—and sometimes, in a world overwhelmed by vast and distant crises, conservation still comes down to the simple choice to care.

Silver watches, both delighted and tired. The fight has been draining. But despite the setback, she says, at least people in Rowe can see what’s possible when folks step up to help birds. “They realize that you can make a difference with your own hands,” says Silver.

This story originally ran in the Winter 2025 issue as “One Nest at a Time.” To receive our print magazine, become a member by making a donation today.