Connecticut is home to as many as 20 percent of the world's population of saltmarsh sharp-tailed sparrows, but climate change is endangering their way of life, according to researchers.The birds have traditionally thrived in the privacy offered by dense saltmarsh grass, but in light of rising sea levels caused by climate change, high tide is more frequently destroying their nests and washing them out to sea, researchers and environmentalists said.
"It's similar to the polar bear; it's one of the poster species for the potential impact for climate change," said Patrick Comins, Audubon Connecticut's bird conservation director, who was instrumental in getting a researcher to study the effect of climate on the saltmarsh sharp-tailed sparrow.
Warmer temperatures and other climate factors are changing the lives of birds who make their homes here, as well as those migrating through, according to researchers and birding experts who are now just getting a handle on the effect these climate changes are having on the various populations.
Climate records indicate that Northeast temperatures have risen by 4 degrees during the last 35 years, according to Cameron Wake, a research associate professor in the Climate Change Center at the University of New Hampshire.
"We're seeing a significant increase in the frequency of extreme precipitation events with more than two inches of rain in 48 hours," he said. "We're seeing sea level rise; we're seeing sea surface temperatures increase."
A warmer planet has been linked to more frequent and intense storms and warmer ocean temperatures, which, in turn, contribute to rising sea levels, Wake said.
"The warming we've seen over the last 40 years is most likely due to humans," he said. "Climate has always changed and always will change, and we know it changes for a whole range of natural causes."
Geological changes, as well as a rising sea level, is likely causing the disappearance, or "drowning," of low-lying marshes, according to Ron Rozsa, a Department of Environmental Protection coastal ecologist.
"When we start to lay historic maps on modern maps, we can actually see this change occurring," he said. "There has been a slow progression from tidal marsh with vegetation to mud flats without vegetation."
This change has reduced the amount of habitat available to the saltmarsh sharp-tailed sparrows and threatened the survival of these birds, according to Chris Elphick, a University of Connecticut ecology professor who has been studying the birds' mating habits and habitat choices. The rising sea level is affecting the high-tide mark and making it tougher for the species to breed and survive, particularly because the birds have a 25-day nesting and incubation period, he said.
"In my view, it is definitely the species that is most likely to be affected by climate change," said Elphick, who began studying the species at the urging of Comins. "It could get very bad, very quickly for them."
The saltmarsh sharp-tailed sparrows typically build their nests in May in high marshes where the dense grass helps keep them relatively safe from predators. But higher tides are now more frequently flooding their breeding sites and washing their nests away, Elphick said.
"These spring tides are generally so high that they flood the nest," he said. "If they go under water, the eggs and the chicks are very likely not going to survive."
While these native species are struggling to survive along Connecticut's coast, other birds, traditionally foreign to this area, are settling in and finding it more amenable than in the past. For instance, black vultures, red-bellied woodpeckers and Carolina wrens were once rare visitors to this colder part of the country, but recently have made themselves at home in and around town, according to Audubon Greenwich birding expert Brian O'Toole.
"Carolina wrens have been expanding northward," he said. "Now they're very common in Connecticut, just like the red-bellied woodpecker."
Some migratory species, such as the Wilson's warbler and the blue-headed vireo, also are staying here longer instead of heading south for the winter, O'Toole said.
"Some of the birds have been delaying migration due to the weather," he said. "They're staying here longer; they're starting to winter here because of the winter."
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