The Wonder of the Bobolink
Tracking the migration and movements of grassland songbirds from Hudson Valley, NY to South America and back
by Amy Wu
At twilight Noah Perlut and his undergraduate research assistants arrived at the farm. The crunch of their rubber field boots filled the cool air as they entered the tall grass. They carried a bevy of items–a toolbox packed with rulers, colored bands to put on birds’ legs, and thumbnail-sized satellite tags, along with mist nets and palm-sized cloth bags to hold birds. Hours before dawn they were already geared up to catch Bobolinks. This was early May.
The Bobolink research initiative launched at the Farm Hub in April. The project is a collaboration between the Farm Hub and Perlut, a professor at the University of New England who has studied Bobolinks for the past 20 years. He is also a member of the Farm Hub’s Applied Farmscape Ecology Research Collaborative, a group of researchers and scientists who focus on studying the connections between farming and ecology. The Farm Hub’s Farmscape Ecology program is keen on learning more about the local Bobolink population on the farm in order to better manage the farmland.
Perlut is deploying geolocators and satellite tags to track the migration and movements of Bobolinks captured at the Farm Hub. He is comparing them with data on birds that he tracked from a farm in Vermont. At 4 a.m. on a recent weekday, Perlut and his undergraduate research assistants set up mist nets to capture the birds. They caught six Bobolinks–five male and one female. They also banded a number of Savannah Sparrows.
“We could talk about their ecology but really I think the most important reason for people to think about is the wonder of the Bobolink, a bird that breeds on a very dangerous place on the ground where there are lots of things walking around that want to eat them and their young. A bird that has a spectacular display and flies around in its bubbly song, and it really defines an agricultural landscape,” Perlut says.
The palm-sized songbirds are distinct with their flat heads, spiky tails, and dramatic aerial displays. In early Fall, from the northeastern US and Canada, they head to Venezuela for a month, fly over the Amazon and land in Bolivia for a month, and then disperse to Argentina and Paraguay for the remainder of winter. The flight pattern is dictated by their search for food. The current research goals are twofold: compare the movement of Bobolinks at the Farm Hub with existing data from birds at the farm in Vermont and explore their movements to nearby properties/farms and with other populations of Bobolinks. Perlut hopes to provide farmers in the region with the data that can help them manage their land and what is grown on the land. For example, Perlut and his crew found four Bobolink nests and banded 14 chicks. Next summer they will search for these birds on the Farm Hub to better understand if birds hatched locally return to breed on the field where they hatched (as is the case in Vermont).
Of the Bobolinks he has tracked on farms he says: “These birds nest in hayfields so their reproductive success is really linked to the timing of which those hayfields are mowed. We will try to better understand what habitats they are using on and around the Farm Hub and when it is particularly relative to when those fields are mowed.”
For Perlut and his team of student researchers, it was a fruitful morning—a windfall of six Bobolinks in a matter of hours. This is not as simple as it sounds. It takes an extraordinary amount of patience to untangle a Bobolink from a net.
After rapidly retrieving them from mist net to cloth bag, the team worked in tandem to tag the birds. They took a blood sample, measured their wing span and beak length, and weighed them. Perlut banded them with three color bands and one numbered metal band. These bands allow anyone with keen binoculars to identify each bird as individuals. Finally, the crew attached a tracking device, much like wearing a backpack. Four of the birds wore satellite tags that transmit the bird’s position to the Argos satellite system, enabling us to follow their movements in real-time. Two of the birds wore geolocators, which collect and store light level and temperature data. Perlut will try to retrieve these geolocators next summer to assess their migration.
How it started
Perlut is based in southern Maine and first began researching Bobolinks as a Ph.D. student at the University of Vermont.
“This project started as my Ph.D. work and continued well past that…I was brought on to start that project in Vermont to understand the relationship between mowing and grazing relative to the birds’ (Bobolinks) reproductive success, and then the project has gone way beyond that goal mostly because of advances in tracking and molecular technology,” Perlut says. His lab focuses on tracking the birds and following their local and international migration patterns to better understand the kind of habitats they are drawn to, related these movements to what they experience on the breeding grounds. Over the course of his career, he has captured more than 4,000 Bobolinks.
Ultimately the goal is to bring knowledge to farmers and landowners so they can balance production and management goals with bird needs.
“We want to see if we can find a balance that everyone gets to meet their objectives. My experience shows that farmers are more likely to adopt creative management strategies when they know more about the individual birds that they steward in their fields,” he says.
Read more about Bobolink research: