It’s 6 a.m., mid-June, and the temperature is already into the 80s at the Washington College River and Field Campus (RAFC). This morning, like every weekday morning unless there is a downpour, interns Sydney Clemmer ’27, Justin Looper ’26, and Andrea McKim ’27 arrive at an unpaved intersection at RAFC’s Grasslands—roughly 200 acres bordering the Chester River where native grasses and plants are allowed to grow. All three interns wear pants tucked into rubber boots to help keep biting insects and ticks at bay. They are prepared to put in as many hours in the field as they can before the heat drives them home.

The students are participating in a study into the behaviors that contribute to breeding success in field sparrows, Spizella pusilla, a collaboration between the College’s biology department and its Center for Environment and Society (CES). A cold, wet spring has been followed by a wet and incredibly hot early summer, and the ticks, mosquitoes, and midges are celebrating a bumper year. The field sparrows, on the other hand, have not fared as well, with few pairs successfully fledging chicks thus far.

The three interns are joined by Jennie Rinehimer, biology professor; Maren Gimpel, director of the Foreman’s Branch Bird Observatory; and Meghan McHenry ’21 of CES. Together, they pore over maps covered in numbers and symbols that record where field sparrows have been spotted, active nests found, and eggs or hatchlings discovered the previous day. Each intern is assigned a plot of land to spend the day observing the field sparrows and recording the observed data on the maps.

Under Rinehimer’s direction, they are participating in a longitudinal study of field sparrow nesting and rearing behavior to determine if parental age and experience influence breeding success. Understanding what contributes to the successful rearing of chicks can aid in the management and restoration of bird populations. Yet studies to date have been inconclusive, in part because it is tremendously difficult to follow populations of birds year after year to gather enough information to make data-driven conclusions. 

Looper says that RAFC’s Grasslands are the perfect real-life laboratory for a multi-year study like this. The bird observatory, which is a federally accredited bird banding station, routinely uses mist nets to capture birds in the area, band them, and collect data. Because resident birds are often captured multiple times in a season, there are already detailed records of many of the field sparrows, sometimes even dating back to when they were fledglings on the Grasslands. According to Looper, having this well-documented population is what makes the study so unusual and valuable.

Looper is a biology major with minors in chemistry and Chesapeake Bay regional studies. He intends to pursue a graduate degree in biology, possibly specializing in reptiles. For him, having fieldwork experience is crucial for gaining admission to top graduate programs. The previous summer, he had an internship studying common terns on Poplar Island in the Chesapeake Bay. “The coolest part for me is kind of how entwined you feel with these birds and how really we can understand that each of them has a personality,” he said. “And, it’s just kind of fun.”

Clemmer is an environmental studies major, a program that requires less fieldwork than environmental science, so she jumped at the chance to get this experience as a paid summer intern. “It’s just a good thing to have on my resume,” she said, “and I enjoy it.” The first two weeks of her internship were spent shadowing one of the three professionals and learning how to identify birds, locate their nests based on the birds’ calls and behaviors, and record the data. After the training, the interns were given responsibility for carrying on the work by themselves.

Clemmer is amazed by how good she has gotten in such a short time at identifying individual birds and interpreting their behaviors. “In the beginning, I was having a really hard time finding nests,” she said. “I didn’t know the difference between them going down into a bush to feed and them going down to a bush because there’s a nest there.” Within a few days of observing the birds by herself, she quickly learned that when a bird is “chipping”—short, sharp sounds—she knows this behavior is associated with an established nest and they are warning her and others away. Once she has located a bird, her first responsibility is to record the location of each individual and what they are doing. Each bird can be identified by the sequence of colored bands on their legs.

For this study, in addition to banding birds with the usual federal band, the bird observatory has been banding field sparrows with different colored bands to identify individuals. They place two color bands on the right leg of each sparrow and one color band on the left leg, above the official federal band. Birds are then identified by the color combinations read from right leg to left, such as Blue Teal Yellow X (where X denotes the federal band). This bird would be recorded on the maps as BTYX. Clemmer uses a spotting scope on a tripod to focus in on the bird’s legs from a distance. She jokes that the birds must know what she’s looking for because they often present one leg and fly away before she can spot the bands on the other. The work requires immense patience because birds can go days or weeks without exhibiting active nesting behavior.

McKim has not declared her major, but is on the pre-med track and is considering doing a biology major and a chemistry minor. She wanted to experience an internship that would take her outdoors. “I’ve always liked the idea of animals but never looked at specific individuals in this much detail,” she said. “I’ve learned a lot about their different behaviors and how they act in different situations.” She’s noticed that males act differently when they are beginning the courtship. They will follow and “guard” the females during the initial mating and nesting phase. When a male doesn’t have a mate, he will spend a lot more time singing and patrolling his territory in the hope of attracting a female’s attention.

McKim did not come to Washington by chance; you might call it a family destination. Her parents are alums who met at the College, and two of her brothers also attended. Both parents work for USAID, and although she was born in California, she grew up overseas, graduating from high school in Jordan.

As well as using spotting scopes and binoculars, the interns are equipped with handheld GPS devices. Once they have found an active nest, they record the GPS coordinates, and these are fed into a digital map that tracks nesting sites across the Grasslands. With each new piece of data, Professor Rinehimer adds to the growing body of knowledge. Field sparrows face a lot of challenges when it comes to successfully raising their young. Chicks are particularly susceptible to the cold, and the amount of rain early this season most likely contributed to so many nests failing. The nests are typically built close to the ground and are vulnerable to predators. “There are a lot of fat snakes this year,” she observed.

For a study like this, good years and bad years are all part of understanding the complex interplay of factors. The question of whether older, more experienced birds have greater success raising chicks remains unanswered, but as the data accumulate, so does our knowledge.

By the end of the summer, the team had recorded 90 nests, which is close to the season average since they began the study in 2017. However, just under 20% of these nests successfully fledged chicks, the lowest rate they have recorded, with the average being nearer 30%.

Looper is philosophical about the role of a scientific observer. “There was a lot of predation this season, and it’s easy to get discouraged,” he said. “But I think it’s important to experience that early on so you understand that even though we’re biologists, it’s not our job to interfere with the natural way that things go.” 

—Darrach Dolan