Decades-long GVSU tree swallow study continually benefits science, students

Michael Lombardo drew data from decades-long research at a tree swallow study site along the southern part of the Allendale Campus for a recently published paper on the most favorable fledging circumstances for the birds to return to the nesting area.

While Lombardo, professor of biology, has wound down his field work at Grand Valley and teaches a limited number of classes, the long arc of research continues to pay dividends both for science and for the students who worked with Lombardo.

The students, some of whom worked under scholarship grants, developed a base of scientific best practices that has helped launch careers and work toward advanced degrees.

"I would tell them that we're not building a cyclotron, but these are basic skills you have to have. You need to be really consistent and really conscientious about keeping notes and doing all of these things that are required scientifically," Lombardo said. "This is an ideal situation for students to obtain those skills; over the years, at least six students have gone on to get Ph.Ds."

As for the study subjects, Lombardo said tree swallows are an ideal bird to research. He began studying them in 1980 as a graduate student.

"They’re easy to study because they nest in nest boxes, like bluebirds do," Lombardo said. "It makes them easy to attract. They're also very tolerant of people studying them; they're easy to attract, catch and handle."

They have distinctive coloration, Lombardo said, with green and blue on top of their bodies and white on the underside. Another interesting fact about tree swallows is it is quite common for a female, who lays eggs once a year, to have offspring with fathers beyond her social mate, Lombardo said.

He set up about 100 nesting boxes for the birds in an area along Pierce Street that used to be all fields but eventually contained retention ponds. Tree swallows prefer such open space, while the ponds were actually beneficial because the birds eat aerial insects.

The most recent paper he was part of, published in the Journal of Field Ornithology, was based on 11 years of research at the site studying whether birds who fledged from a certain area returned to breed as adults. 

Lombardo said the findings were that there is a "Goldilocks effect" for that scenario. Nestlings who fledge too soon tend to find difficulties including inclement early spring weather, while those who fledge too late tend to not develop the physical capabilities necessary for migrating. The research found a time period in the middle that was optimal for "local recruitment."

Jessica Dreyer, '14, said her undergraduate experience working with the tree swallow research helped set her on track to pursue a doctorate in ecology and evolutionary biology. She quickly developed an interest in wildlife research and found a good opportunity with Lombardo.

"Dr. Lombardo was a pretty outstanding mentor, and it was sort of my first entry into biological research," Dreyer said. "I enjoyed being outside interacting with nature and the environment as well as learning how to hold a bird and learning good scientific practice in the field."

Learning the proper way to hold a bird has also been helpful for Emma Sachteleben, '20, who is working at an animal hospital.

Sachteleben spent three years on the project and was fascinated to learn how much variation there is in species. Much of Sachteleben's later work was in analyzing data, which also provided valuable skills.

"It taught me to take other people's research and connect the dots," Sachteleben said.

Those experiences are why Lombardo is grateful colleagues are using the study site for current students to learn about research skills with wildlife. And his work with tree swallow data, which benefits from its longevity to study trends, continues on; he recently did a poster presentation on nest box occupancy for the virtual North American Ornithological Conference.