For barn swallows, it’s a struggle

Five years into their Big Barn Study, Westport-based researchers have mixed news about those agile mosquito-eating machines, the barn swallows.

Struggling through much of their range, the birds are very much alive and well in select South Coast locations, although even here they face challenges, said Lauren Miller-Donnelly of Massachusetts Audubon at Allens Pond sanctuary in Westport.

“Some places they have been so successful this season and in recent years that they have been able to start a second nest,” she said.

At other barns where they were once abundant, “they are just hanging on … maybe one nest.”

Ms. Miller-Donnelly and her team of student assistants began their work in 2014 and this summer have been keeping watch over 15 locations around the area.

“We are near the end of the season now,” she said recently — it’s nearly time to migrate south.

A “wondrous migrator,” according to bird researchers at Cornell University, barn swallows migrate to winter grounds in South America — some fly nearly 12,000 miles to as far south as Argentina.

The local population will soon be gone, replaced for awhile by travelers from further north that are just passing through, pausing long enough to dine on bugs.

When they started their work, the Westport researchers put word out that they are seeking places where people see lots of barn swallows — big old barns are the best candidates.

“We’ve found some amazing ones,” some quite close to home.

During a late June visit to the massive barn at Westport Town Farm, Ms. Miller-Donnelly and staff were greeted by swallows zipping about. They used mirrors on poles for a look up to the rafters and inside the cup-shaped mud and horse-hair or grass/straw nests and found plenty of activity.

Of 25 nests found, 80 percent were successful after a wet spring, she said. Those successful nests averaged six eggs each and, later, about five chicks. Actual fledging numbers weren’t yet in.

One of the most prolific spots isn’t a barn at all — it’s Tripp’s Boat Yard.

Paddling in kayaks beneath the docks there and watched by annoyed birds, they counted 30 nests, most of which seemed to be doing well.

"They are turning up in places you'd expect, big, old barns whose owners keep a door or window open, lots of rafters … they are called barn swallows for a reason." One "amazing barn" at Nonquid Farm in South Dartmouth, a pitched-roof barn with hay loft and patchwork of beams, has had up to 25 nests some seasons.

Another good one is at the Howland Alpaca Farm.

But even in the best places there are challenges, perhaps foremost the house sparrow (aka English Sparrow, or, to the birds’ many detractors, “flying rats”).

Barn swallows and house sparrows like to nest in similar places and that seldom goes well for the swallows. House sparrows don’t tolerate other nests in what they view as their territory and are merciless when they find them, killing any chicks they find. These imports from across the Atlantic are just as lethal to bluebirds and other native species.

“Those swallows that nest in a secluded back corners of the barn tend to do better. The less experienced ones that nest closer to the door where they are more exposed to house sparrows, their chances are much worse,” Ms. Miller-Donnelly said.

At Triple S Farms off Horseneck Road, they found one lonely swallow nest still hanging on — house sparrows had apparently decimated the rest.

Those lucky (or clever) swallows that select docks, like those are Tripp’s, have an advantage.

“There are fewer predators there — cats, raccoons,” although even here they aren’t entirely safe from house sparrows.

While the researchers are encouraged by initial findings, Ms. Miller-Donnelly said barn swallows are facing an uphill struggle for many of the same reasons that other birds are on the decline.

Big, old barns — the kind with open doors or holes in the wall — are disappearing. Others are being restored, and once fixed up and filled with valuables are no longer welcoming to barn swallows.

And bug eating birds in general are having a tough time, she said — pesticides and spraying may have something to do with that.

Swallows — we need them

We should care about how all native species are faring, she said, but Ms. Miller-Donnelly has a special fondness for these birds.

Agile flyers, they are adept at plucking bugs, mosquitos among them, out of mid-air. That's especially good news on farms whose owners worry about EEE and other deadly mosquito-borne diseases on their animals and themselves — Triple E has claimed the lives of several horses here in recent years and was recently found in tests on mosquitos in Tiverton.

Beyond that, "Barn swallows are like the poster bird of warm summer evenings. They are out there flying about, eating mosquitos, saying good night … beautiful birds."

Want to help?

The study will continue in hopes of establishing regional population baselines and learning more about what the birds need to succeed. They also hope to learn more about migration patterns, as has been done with osprey.

If you would like to join the Big Barn Study or if you own a barn or large dock where swallows are present and would be willing to allow a study participant to briefly observe swallows on your property, email allenspond@massaudubon.org  or call 508-636-2437. Property owners from Westport, Dartmouth, Tiverton, Little Compton — anywhere nearby, are encouraged to participate.

They'd especially like to hear from people who own big old barns, the sort where barn swallows live and where the population can be followed over a period of years.

"That's really the only way we are going to be able to draw conclusions about how they are doing here … over time."