At the 36-acre salt marsh at Jacob’s Point in Warren, R.I., Deirdre Robinson wanders among three mist nets she sets up at dawn every morning from late May through mid-August in an effort to capture the rare saltmarsh sparrows that nest there. The birds are predicted to go extinct in the next 15 to 20 years, as rising sea levels flood marshes throughout their range along the East Coast.

Robinson and a team of other volunteers are attempting to document the fate of every nest built and every egg laid.

“I’m drawn to the exceptions to the rules, and this bird is the exception,” said Robinson, a retired physical therapy professor at the University of Rhode Island who has been interested in saltmarsh sparrows since the 1990s. “They’re non-territorial, they prefer to run than fly, their breeding system is based on promiscuity, the female does all the nest building and feeding, and they don’t really even have a song, just a rudimentary whisper.”

At one net, she disentangles a female bird to read the numbered band on its leg to trace its breeding history at the site. Checking a log book, she notes that the bird was first banded at Jacob’s Point in 2018 and has now nested here at least three years in a row.

In the first week of June, the high tides were the highest of the month, and most of the nests were expected to become flooded. If the eggs hadn’t hatched by then, they would probably float away on the tide; if they had, the chicks would likely drown.

“She’ll probably lose her nest tonight, and then she’ll likely try again next week,” Robinson said of the bird in her hand. “If she nests in a slightly higher location, she might succeed next time, but not if she nests back in the flood zone again.”

When Robinson photographed a banded saltmarsh sparrow in 2016 at Jacob’s Point — a property owned and managed by the Warren Land Conservation Trust — she was inspired to investigate where it came from. She eventually tracked it to a bird bander in Pinellas County, Fla., which gave the bird the distinction of having migrated the longest distance of any saltmarsh sparrow ever recorded.

The discovery inspired Robinson to contact amateur ornithologist and master bird bander Steve Reinert and launch a research project.

“We figured that if we found a bird banded in Florida, why couldn’t they find one of ours,” said Reinert, who retired from Lifespan in March and leads bird-banding programs for the Audubon Society of Rhode Island. “Our goal is to find every nest and get bands on every female at every nest and band every male we can, and then determine the elevation and vegetation composition of every nest.

“If I were more optimistic, I’d say the excitement of the study is contributing to identifying optimal nesting habitat for saltmarsh sparrows, doing it by finding lots of nests and knowing what happens at every nest, and documenting the characteristics of those nests.”

But it’s difficult to be optimistic for the future of this species.

“The birds aren’t aware of the tides,” Reinert said. “They just come in, mate, build their nests, and lay their eggs. By experience or selection or whatever, they cluster their nests in a higher part of the marsh. But we had one bird that put her nest in the lower part of the marsh, and her nest got flooded last night.”

The year’s first nesting attempt by each female saltmarsh sparrow typically fails when the nest is flooded by the highest tide of the month. But that allows the birds to synchronize their next nesting effort with the tides.

It takes 28 days — the same number of days between lunar cycles — for the birds to build a nest, lay their eggs, incubate them, and raise their chicks until they are mature enough to escape the rising tides.

“If all goes well, their young will be strong enough to climb out of the nest into the high vegetation to avoid being drowned,” Reinert said. “It’s so closely timed that some of the clutch might climb up and survive and others won’t.”

But as the tides rise higher and higher because of the climate crisis — some predictions suggest it will rise 2 more feet by 2050 and 7 feet by 2100 — the marshes will become completely flooded and the birds will disappear forever.

Nonetheless, the research team is revealing some unexpected findings about the saltmarsh sparrows at Jacob’s Point. Among the most notable is that the marsh is home to many more sparrows than anyone would have guessed. Last year the volunteers documented 84 saltmarsh sparrows at the site — 53 males and 31 females.

“This is a really healthy marsh with a lot of birds nesting here, so we hope that makes it a high priority for possible intervention or restoration,” Robinson said.

By recording the location of more than 100 nests in the past three years — many found by 17-year-old Joel Eckerson, another member of the project team — the researchers have also noted that the birds cluster their nests where the marsh elevation is highest. It’s a strategy to avoid flooding that succeeded prior to this era of rising waters, but not anymore.

“It’s depressing,” Reinert admitted. “But I guess I do this work out of curiosity. I find us in a unique position to document this species through its period of extinction.”

Robinson gets depressed when she thinks about the future of the saltmarsh sparrow, too, but she tries to put a good spin on it.

“Extinction is a natural process, though this extinction won’t be natural — it’s completely anthropogenic,” she said. “But we bring a lot of young people to see the project, and they get excited by it. So I try to channel it into something positive, like preparing these young people to study other species.”

The fourth member of the research team, Jim O’Neil, is more hopeful.

“I think this is a way we can figure out how to save this species,” he said. “I’m hoping the birds will make it. Maybe what we learn can help save the species.”

It’s a sentiment many bird lovers feel. But by all accounts, it’s not realistic.

Rhode Island resident and author Todd McLeish runs a wildlife blog.