Block Island bird study reveals some good news for island’s migrating songbirds

Block Island welcomes scores of tourists all summer long, with the Block Island ferry pulling into port 15 times a day. Come fall, new visitors arrive: migrating birds by the thousands.

This fall, a new University of Rhode Island graduate is publishing some good news on their numbers.

Lauren Michael, who received her master of science degree in biological and environmental sciences in May, analyzed 66,288 birds from 22 species, which visited the island between 1970 and 2021. Her coauthored paper, with URI professor of natural resources science Scott McWilliams and Steve Reinert ’75 ’78, on songbird levels on Block Island will be published in the November issue of Ornithological Applications.

The banding station was established on Block Island by Elise Lapham in 1967, providing the foundational work for long-term study of bird populations on the island.

The Hopkinton resident came to URI with a decade of experience studying birds at sites across North America, before making her way to the island nine miles off the coast of Rhode Island that’s an important stopover site for migratory birds. The bird monitoring station, known as the Block Island Banding Station, was established by Elise Lapham in 1967. She operated the station each fall and spring alongside her daughter, Helen Lapham, and Kim Gaffett, who joined in 1981. Gaffett, now a naturalist at the Block Island office of The Nature Conservancy, has continued the banding operation to this day.

Michael says that stepping into a project started before she was even born was a humbling experience and credits the Laphams and Gaffett for their decades of commitment to the study of birds on Block Island.

“Without their dedication, this project would not have been possible,” she says. “The Block Island Banding Station is one of the longest continuously running bird banding stations in the country. All of these women were volunteers and dedicated decades of their lives to this study.”

Island destination

While Block Island is known as a draw for the young each summer, that’s true of the fall bird visitors, too, for different reasons.

In fall, young birds undertake their first migrations south. Inexperienced, they are disproportionately pushed to the coast, while adult birds opt to stay inland, where it’s safer, away from open water.

This southern New England “coastal effect” gets an added push from overnight north-west winds, meaning huge numbers of these young birds are pushed out over the water and end up on Block Island. As a result, most of the birds captured on Block Island are young. The exhausted and inexperienced birds find a good stop-over in the fruiting shrubs that cover the island, getting a brief rest and nutrition before continuing their journeys.

Michael’s paper strikes a somewhat positive note as bird populations in North America have declined at an alarming rate, with an estimated loss of 3 billion birds since the 1970s. Many songbirds saw drastic declines through the 1980s, possibly from changes in weather, local land use and habitat, or cyclical breeding.

Eighteen of the species studied on Block Island saw a sharp decline in the 1970s and 1980s, followed by stabilization, recovery, or slower decline for the remainder of the study. These steady numbers are cause for celebration — and education. With increasing pressures on these birds, determining which species are at the greatest risk is vital.

The team used “breakpoint” models to identify changes in abundance trends over time. Although applying this kind of model to bird banding data is novel, these models have been used in ecological research and in other disciplines. These models are applicable anytime you see or expect an abrupt change in slope in response to something, Michael says — similar to a stock market crash, response to a new social policy, or a physiological response to a medical treatment. In wildlife biology, they’re used to identify changes in physiology, find ecological thresholds, or detect sudden changes in abundance.

While species analyzed on Block Island have not fully rebounded to their 1970 abundance, their sustained recovery since the declines in the 1970s and 1980s indicates that environmental conditions may be adequately supporting these smaller current populations.

“Had we interpreted these trends using the entire 52-year time series, outside of a breakpoint model, as other studies have, we would have concluded that these species had simply declined,” says Michael, “rather than acknowledging that though they may have dramatically declined in the 1970s and 1980s, they have been recovering over the last several decades.”

Michael found that 18 species with breakpoints exhibited a consistent pattern: a steep decline in abundance within the first two decades of the study, followed by stabilization, recovery, or a more gradual decline. After the breakpoint, most species were stable; many even showed increases. Fourteen of the 18 species recovered relative to 1970 levels, and two — the Blue-headed Vireo and Eastern Phoebe — even made a full return. Only Gray Catbirds continued to decline after their breakpoint in the late 1970s, though at a much slower rate.

Michael hopes to take the inspiration she found on Block Island to make environmental education and science communication a larger part of her career, leaving URI with a memorable souvenir of her academic studies in the Ocean State.

“Block Island is an incredibly unique place to study birds,” she says. “This was more than data; it’s really the culmination of decades and decades of people’s lives and dedication. I was honored that I got to be a small part of it.”