“This course was very independent and student-led. We were sent out with a notebook, not a set protocol. We had the freedom to develop questions and be in charge of our research in a way I haven’t been before in a classroom or lab,” says Boyle.
One of the questions that Boyle’s group explored was whether the squirrels choose their habitats based more on human interaction or on ecological factors like access to trees that produce more food or offer better shelter.
“We found it’s an even mix,” she says. “Humans represent a reliable food source but also a potential danger from kids and dogs.”
Willow trees near the pond were the most popular habitat, Boyle found. They’re easy to hollow out, easy to climb, and attract many regular visitors who feed the squirrels consistently.
Boyle’s team reasoned that space, rather than food, is the limiting factor in how many squirrels inhabit the Public Garden. Man-made barriers — busy streets, clusters of houses — make venturing to nearby green spaces like the Charles River dangerous.
Lopez and Ghazi focused on communication among the squirrels.
“Squirrels play a lot, but not on the trees where they live,” says Ghazi. “They use a lot of vocal communication. They bark, yell, and they use tail movements, too, especially when they’re scared by loud trucks, sports cars, or aggressive dogs. When they’re frightened they yell and jump in and out of trees.”
Nolfo-Clements will continue the research with students in coming years. Though permission through Boston Parks & Recreation and the university’s animal care and use policies prevent her and her students from tagging or marking the squirrels, she hopes to eventually gain permission for genetic testing through hair sampling.
For now, they’ve learned to keep track of individuals based on their colors and the shapes of their tails, says Lopez. They’ve even named some — and she can point out Eli, Marcus, Scott, and Red as she walks through the park.
Boyle identifies her subjects by their homes:
“One tree is very syrupy, so we can always spot the squirrels that live there by their messy fur,” she says.