There’s little about a Snow Bunting that isn’t perfectly suited to life in the deep freeze. These winter wanderers are outfitted like little polar explorers, with a natural down parka of dense white feathers that cover even the birds’ ankles and base of the bill—and keeps their exposure to cold at a minimum.
The adaptations are more than skin deep. A Snow Bunting’s body temperature can dip 30 to 40 percent lower than other songbirds their size before hypothermia sets in. As weather conditions deteriorate, Snow Buntings can adjust their metabolism to quickly turn food into insulating body fat. And when the cold air arrives, they bury themselves in snowdrifts for warmth.
All these feats add up to a species that breeds farther north than any other songbird, returning to its Arctic nesting territories in March and singing its heart out when temperatures can still drop well below zero. Snow Buntings are so hardy, in fact, that the only time most people get to see them is during winter, when flocks magically appear and disappear over snow-blown northern fields, seemingly undeterred by what we call winter.
For bird watchers, the little bird with a toasted marshmallow pattern is a bright spot in a gray winter. In eastern Canada, Snow Buntings have even inspired a citizen-science project. Started in 2006, the Canadian Snow Bunting Network has been collecting data on their occurrence during winter across almost all of the Canadian provinces. Now scientist Oliver Love is using the network’s extensive data set, along with his own findings from tracking individual birds, to open up a window on where these mysterious birds live their lives, and where they go when the weather gets bad.
In 2007 Love, of the University of Windsor, Ontario, and research associate Rick Ludkin came across a report of Christmas Bird Count data that suggested Snow Bunting populations had declined an alarming 64 percent in the last 40 years. The decline was attributed largely to a warming climate. “I was convinced it couldn’t be as simple as climate change,” explains Love, “and I was curious as to how the 64 percent was derived.” He decided to investigate.
Sadly, it’s not uncommon for songbirds to suffer such severe declines. Nearly four dozen other species have declined by more than 50 percent since 1970, according to the bird conservation group Partners in Flight. But Love knew that Snow Buntings were a special case. For one thing, they move around a lot, and it’s hard to measure populations of a species that show up in great numbers one year and are nearly absent the next. Furthermore, if climate is altering where Snow Buntings spend the winter, warming temperatures are liable to push them north, away from places where birders are most likely to find them. In both scenarios, the birds might not be declining, they just might not be getting counted.
To take a second look at the situation, Love turned to the Canadian Snow Bunting Network.
David Lamble, a member of the Canadian Snow Bunting Network, retrieves a Snow Bunting from a live trap in Ontario. The bunting will be banded, released, and added to the network’s eight years of citizen-science data. Photo by Emily McKinnon.
For decades, bird banders have trapped Snow Buntings in live traps made of wire mesh and baited with cracked corn. The birds typically walk right in and get caught, making them an easy species to work with. Until 2009, the Canadian Snow Bunting Network was an informal operation, sort of a ragtag community of bird banders primarily in Ontario, with each bander more or less keeping their own records. Some were scientists who kept meticulous notes about the birds’ ages, sexes, and body conditions, while others were in it for the fun of operating an outdoor wildlife project for schoolchildren. All were people who just loved these hardy little birds and wanted to work with them.
Love formalized the process by connecting this disparate network of enthusiasts and recruiting experienced banders into the project. Soon there was a formal protocol for banders to follow and an annual newsletter, The Snow Bunting Report, that summarized each year’s progress, distributed tips for identifying a bird’s age or sex, and shared new research that the network was helping to inform. Each of the dozen or so banding groups in the network was recording detailed measurements, along with age and sex information. Some were even pulling feathers for isotope analysis, a lab technique that can reveal where individual birds have come from. It wasn’t long before patterns began to emerge.
One of the first things Love and his research partners noticed was a correlation between local conditions and gender: the colder a given location, the more likely the flocks would be made up of males.