19 Jan
2018

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By Hugh    No Comments

Watching the Titanic: Salt Marsh Sparrows and Sea Level Rise

Drawing by Evan Lipton

A pair of dedicated citizen scientists have spent the past year studying a bird that is small in size but large in significance: the Salt Marsh Sparrow. Along the way, they learned a lot about the bird’s behavior and flight abilities. Yet the excitement of the research was tempered with one stark fact: in a relatively short time, the birds will no longer exist.

Steve Reinert and Deidre Robinson discussed their work in a recent presentation sponsored by the Ocean State Bird Club (www.oceanstatebirdclub.org) . The pair coordinated a season-long study of the sparrows at Jamestown’s Jacob’s Point Marsh, assisted by artist Evan Lipton and URI Research Assistant Katie Christ.

Although the Salt Marsh Sparrow can be found nesting in places like Galilee and Colt State Park, the team was drawn to Jacob’s Point in part because of a record-breaking discovery. “In July of 2016, we spotted a sparrow with bands on her legs,” said Reinert. “We know it was a ‘her’ because we were able to get the numbers from the bands. It turned out that the bird had been banded in Florida back on Halloween of 2015. That meant the bird had traveled some 2000 km. (1250 miles), which turned out to be a record setting migration. That’s what got us going on this location.” Robinson agreed that the find was surprising. “When you band a bird, there is less than a 30% chance of its return to the area. When you get a bird that’s two years old, that’s cause for celebration.”  Reinert and Robinson received permission to do their research from the Warren Land Conservation Trust, and they were off.

One of the first tasks was to capture and tag the birds. A team of volunteers walked along the creek ditches found in the marsh carrying long poles with netting strung between them, essentially sweeping the birds into the nets. To make long distance identifications easier, Reinert placed four bands on their legs. The color choices and patterns formed a code that would allow observers from around the migration area to make an identification of where the bird had been tagged, its sex, and the date it had been tagged, significantly increasing the knowledge without the need for recapture.

Robinson said the numbers tagged exceeded expectations.  “I hate to overestimate, and I tend to be very conservative about how many birds we’ll find.  We thought there might be seven adult birds to be banded, and we ended up banding 84. To me, that was quite astounding.”

Photo by Deidre Robinson

When it comes to the job of rearing sparrow chicks, there is a stark difference between the  sexes. Males exhibit what is known as promiscuous behavior; their sole responsibility in continuing the species involves seeking out and mating with as many females as possible. Once the male mates, he is off to find the next female, leaving incubating and rearing his progeny completely in the hands (or beak) of the female. She will build a nest in the highest, driest part of the salt marsh. Even with her best efforts, there is only a 25% chance that one of her young will fledge (learn to fly and survive on its own). The rest will be lost to predators like crows or herons, or simply to time.

“Every 28 days, the tide is high enough to flood every nest on the marsh,and so there’s a race for the birds to complete their breeding activities,” said Reinert. “The birds engage in this race against the tides every year.”

In another part of the presentation, Robinson showed a series of film clips of the Salt Marsh Sparrow’s behaviors. She pointed out ways in which they regulate their body temperature (thermoregulation), stay on the lookout for predators, and even show their preference for running over flying as a method of moving. “Running is much more economical when it comes to energy efficiency,” she said. She pointed out that technology has been a boon to the process of gathering knowledge about their behavior. “Being able to record the sparrows without disturbing them is so important. Then there are the increases in the quality of the optics, along with the ability to GPS the location of each nest to understand spatial distribution. Even using cell phones to report in from different parts of the marsh have made the research so much easier.”

Despite the ongoing learning, there is an air of fatalism about the bird. Salt Marsh Sparrows need high areas of a marsh that stay dry most of the time in order to reproduce. Climate change is resulting in rising sea levels which, in turn, are gradually drowning salt marshes. No marshes, no Salt Marsh Sparrows.

Photo by Deidre Robinson

“It’s kind of like watching the Titanic and knowing what’s going to happen,” said Robinson. “If we can learn the habits of one species and apply the knowledge to another, hopefully we could help another species. Sea level rise and human alterations of Salt Marsh Sparrow habitat has had irrevocable consequences.”

In the immediate future, though, the team hopes to continue their research. “We would like to do it for four more years to get a really good dataset,” said Robinson. “We have about a dozen volunteers who range in age from nine to about seventy. We’re a self funded project, and we’d like to find other birds, other nests, and continue to get some good pictures of their behaviors. ”