During the course of her studies on the Bobolink throughout the western hemisphere, Dr. Rosalind Renfrew of the Vermont Center for Ecostudies has captured and recruited 433 of these charismatic songbirds as research subjects. On the right leg of each she places a tiny aluminum bracelet bearing a unique number, a bit like an avian Social Security number. Renfrew then releases each bird to fateful winds, hoping against all rational odds that some day, somewhere, anywhere, one of them will be recaptured.
Banding a Bobolink in S. America
Banding a Bobolink in S. America
Bobolink No. 0961-10071 got his bracelet while Renfrew was working in a rice field in San Juan, Bolivia, on January 30, 2006. Then he was gone.
“The odds than any of these Bobolinks would be found anywhere, dead or alive, were essentially zero,” says Renfrew, a biologist with the Vermont Center for Ecostudies in Norwich, Vermont. “They could be flying in a range that extends thousands and thousands of square miles.”
But just this past spring, three and a half years after she had banded him, in what could only be described as a case of avian shock and awe, Bobolink No. 0961-10071 turned up in Vermont. Renfrew had expected to win the lottery before relocating this bird – and she doesn’t even play. And here’s what is most amazing about this impossible discovery:
• Bobolink No. 0961-10071 was rediscovered at least 4,300 miles (as the crow flies) from where he was banded Bolivia. This marked the first time a Bobolink banded on its wintering grounds had been recovered on its breeding grounds (or vice versa).
• Because Bobolink No. 0961-10071 turned up three years after he was banded, he flew at least 35,000 miles in migration between South America and North America before that fateful June day in Vermont.
• Bobolink No. 0961-10071 was found in Chelsea, Vermont, only 12 miles from Renfrew’s home.
“I’m still shaking my head in disbelief,” says Renfrew. “To catch a songbird on its wintering grounds in South America and have it turn up essentially at my door thousands of miles away, well, it’s practically impossible.”
Finally, and poignantly, Bobolink No. 0961-10071, after flying all those miles, came to Renfrew’s attention only because he was delivered to a homeowner by a house cat.
The Bobolink’s odd, electronic song and flashy yellow-white-and-black plumage make it a charming summer songbird. Welcomed each spring to meadows, pastures and other grasslands across North America, Bobolinks aren’t always well received in South America each winter. There they feed in commercial rice fields, where farmers consider them agricultural pests and use pesticides that are highly toxic to birds.
“Rice may be a bit like fast food,” says Renfrew. “It’s easy to get but can be unhealthy for Bobolinks.”
In earlier research trips to South America, Renfrew found Bobolinks gathered into remarkable groups numbering up to 130,000 birds and feeding in rice fields. The discovery was exciting yet worrisome. Scientists and conservationists have for decades tracked a steady decline in Bobolink populations.
“So many Bobolinks concentrated so densely makes them more vulnerable,” Renfrew explains. “If only a handful of these large flocks were to disappear, we could lose a significant portion of a population that is already depleted.”
With a prestigious grant from the National Geographic Society, Renfrew is using innovative technology and science to track and study Bobolinks. She is analyzing feathers to determine the degree to which Bobolinks rely on commercial rice fields. And she is equipping some Bobolinks with geolocators – tiny “bird backpack” devices that actually track a wandering Bobolink’s whereabouts throughout the year.
As it turned out, Bobolink No. 0961-10071 could not be salvaged. Yet it unwittingly established for Renfrew a direct link between Vermont and Bolivia.
“When I travel by plane from my home in Vermont halfway across the hemisphere to study these birds, I gaze out the window and try to imagine a bird weighing only an ounce making that same journey” she says. “The life and death of this particular Bobolink, its amazing feat of migration, and the connection between the continents is now more real for me than ever.”