Michael Walsh remembers seeing his first Carolina wren many years ago, a sighting that would not be so noteworthy if it happened today. It’s not that the plump, brown bird has become less beautiful – it’s that the bird is becoming increasingly common hereabouts.
Walsh is an avid bird watcher and the vice president of the Ascutney Mountain Audubon Society in Vermont. Every year he participates in the Audubon Christmas Bird Count.
The Christmas Bird Count is a nationwide survey of early winter birds. It is organized by local Audubon Society chapters and has taken place across the country for over a century. Counts will take place this year in Vermont and New Hampshire from December 14 to January 5.
Walsh first saw a Carolina wren during a Christmas Bird Count. As its name suggests, the Carolina wren is a southern bird. Until recently, southern New England was the northern edge of its range. Seeing the bird in Vermont was unusual. Seeing it in Vermont in the middle of December was stranger still.
Over time, Walsh’s sighting turned out not to be that odd. As years have gone by, the number of Carolina wrens seen during the Christmas Bird Count in Vermont and New Hampshire has been steadily increasing. In fact, it’s not at all unusual to see one now.
The Carolina wren is not alone. A number of formerly southern birds are now seen regularly during the Christmas Bird Counts across New Hampshire and Vermont.
Tufted titmice started appearing in the count about 10 years ago, Walsh recalls. Red-bellied woodpeckers used to be rare in Vermont at any time of year. Now they are commonly seen during the count, as are turkey vultures, and other birds previously only found to our south.
What’s going on here?
We’ve had mild winters over the last few years, including more brown Christmases than we’d like. Could the Christmas Bird Counts be the result of a short-term reaction to those balmy winters? Or something more long-lasting? One way to find out would be to see if these southern birds are also breeding locally in the spring.
“It’s definitely happening,” says Rosalind Renfrew, the Vermont Institute of Natural Sciences biologist who is in charge of the Vermont Breeding Bird Atlas.
The Vermont Breeding Bird Atlas is a serious bird survey that takes place once every 25 years in Vermont. Dozens of volunteers look for birds in every part of the state during the birds’ breeding season, roughly from May to August. It’s a five-year effort now in its fourth year.
So far, the results show a whole suite of southern species turning up more frequently as breeders in Vermont, Renfrew says.
These birds include the tufted titmouse, northern cardinal, red-bellied woodpecker, Carolina wren, and the turkey vulture. It’s a very similar list of species to the birds turning up in the Christmas Bird Counts.
But why is this happening? Renfrew says the answer won’t be found in the Breeding Bird Atlas, which only records where birds are found, not why they are found there. She notes that for birds such as the tufted titmouse, some studies suggest that the presence of bird feeders has made northern living easier.
She’d like to see more studies that get to the root of why we’re seeing more of these southern birds. For some scientists, however, there is already enough information.
“It’s climate change,” says Dr. Hector Galbraith, a researcher based in Dummerston, Vermont, who studies the ecological impacts of climate change.
I’ve been interviewing scientists for 17 years now, and their favorite phrases usually run to, “the data suggests,” “it appears that,” and “we need more study.” In contrast, there is no waffling in Galbraith’s statement, and when asked, he confirms that none is needed.
“There are a whole bunch of data sets that show the same thing,” he says.
“All of the Vermont Christmas Bird Counts show a steady increase in southern birds wintering in our area. The Vermont Breeding Bird Atlas is showing southern birds breeding in our area.”
The breeding bird atlases for New York State and the Canadian province of Ontario show the same thing. So it’s not just a Vermont phenomenon, but something that is happening across New Hampshire and the whole region.
The two Christmas Bird Counts conducted by the Ascutney Mountain Audubon Society are taking place this weekend, in two towns along the Connecticut River. The Saxton’s River count will take place on December 16, and the Springfield count on December 17.
The trend of more southern birds being found in our region has held for over 10 years. There is every reason to expect this year’s counters again will be greeted with the avian version of “Hey, y’all,” from the southern birds who have made a home in our region.