Update: Rockwell’s presentation now is available online.
Click the link and use the password v1R$ErPy to watch it.
A Kalamazoo College alumna will deliver a public virtual presentation through the Redwood Region Audubon Society (RRAS), highlighting the incredible journeys of two varieties of migratory birds including one that was found through her research to fly from Oregon to Brazil and back.
Dr. Sarah Rockwell ’02 works for Klamath Bird Observatory (KBO), a scientific nonprofit research organization in Ashland, Oregon, that focuses on achieving bird and habitat conservation through science, education and partnerships. Rockwell’s program, “To Southern California, Brazil, and Back: First GPS Tracking of Oregon Vesper Sparrow and Western Purple Martin Migration,” will be available through Zoom at 10:30 p.m. Eastern time Thursday, January 16, at rras.org.
Rockwell joined collaborators from the U.S. Forest Service, the U.S. Geological Survey and Cape Arago Audubon to work after dusk with purple martin bird colonies along the Oregon coast and at Fern Ridge Reservoir. Equipped with headlamps, they captured adult birds roosting in their nest boxes between about 9 p.m. and 1 a.m. and tagged them with a small GPS device. The next morning, after sleeping in tents, Rockwell and her collaborators observed the tagged birds to ensure their normal behavior, including flying and feeding their nestlings.
Separately, Rockwell worked with KBO Director of Conservation Jaime Stephens to study Oregon vesper sparrows. Together, they set up a mist net near a perching spot in a male’s territory and placed a speaker playing a vesper sparrow song under it. The birds perceived the song as a rival male, often causing them to fly into the net while trying to chase away the false intruder, allowing Rockwell and Stephens to band them.
With both species, Rockwell and her collaborators made harnesses so the birds could comfortably wear the GPS tags like a backpack with loops going around their legs. Rockwell then waited almost a year for the birds to complete their round-trip migrations so they could be collected for data retrieval as GPS tags for birds this small are too lightweight to transmit data, only store it.
Their efforts have proven successful.
“Before this study, we did not know where purple martins from Oregon went during migration and winter,” Rockwell said. “The unique subspecies of the western purple martin is estimated at just 3,500 pairs in the Pacific Northwest states, and it is considered to be of conservation concern. We had the same questions for the Oregon vesper sparrow, another subspecies unique to the Pacific Northwest that is currently under review for listing as threatened or endangered due to its small population size and declining trend. These are the first studies of their kind with these subspecies, tracking them with GPS tags year-round.”
As a student at K, Rockwell participated in the ecology and environment study abroad program in Ecuador. Through that program, she participated in field trips with an ornithologist that helped her and other students spot and identify birds. At the Tiputini Biodiversity Station in the Amazon, she also participated in a three-week bird survey, spending time in canopy towers counting birds and adding to the inventory at the station.
“It is hard not to fall in love with tropical rainforest birds like parrots, toucans, tanagers and hummingbirds,” Rockwell said. “When I returned, I took a vertebrate biology class with Dr. Paul Sotherland, which had a substantial bird component. When I found that I also loved learning the birds of Michigan, I took that as a good sign. My first field jobs after college were working with sea turtles and then endemic forest birds on the big island of Hawai’i at Volcanoes National Park. This is where I learned how to mist-net and capture birds. The first time I held a wild bird in my hands, I was hooked.”
Rockwell earned a job with KBO after completing her Ph.D. at the University of Maryland and Smithsonian Migratory Bird Center. Fast forward 12 years and she’s now working there as a senior research biologist. In her position, she hires and supervises field crews and conducts field work from April-July. That means getting up early and spending a lot of time hiking and studying birds outdoors. The rest of the year, she pursues data management and data analysis using statistical software, writes reports and peer-reviewed publications, seeks grant writing opportunities, and plans for the next field season.
In her upcoming presentation, Rockwell said attendees can expect to see photos and maps from her research, and peek into where western purple martins and Oregon vesper sparrows go during the annual voyages they undertake.
“These first few birds have returned with fascinating information, revealing new discoveries about their incredible journeys, including unexpected lengthy fall stopovers, and for purple martins, winters on the beach in southeastern Brazil,” she said. “Determining the factors that limit population size in a migratory bird species can be challenging. It requires understanding what threats they may face in different parts of the year, and thus, the first step is knowing where they are throughout their annual cycles. A better understanding of overwintering locations and migratory stopover sites used by Oregon vesper sparrows and western purple martins, and potential threats originating during the non-breeding season, are key information gaps needed to target conservation actions.”
