Harper, a great blue heron (Ardea herodias), could win a prize for endurance. This fall, after leaving her post-breeding area in Pointe-à-la-Croix, Quebec, Harper flew 68 hours nonstop (61 hours over open ocean) – a total of 2,030 miles – to Cumberland Island, Georgia. She stopped to rest and feed, then continued her migration to Cuba. A star of Maine’s Heron Tracking Project, she is one of three herons currently carrying GPS transmitters that track their migration. This data provides biologists and citizen scientists with information that will help guide future management of heron populations and habitat conservation in Maine and throughout their range.
Great blue herons are often reflected in art and literature as a symbol of grace and beauty – some even consider them spirit guides. Supremely efficient predators at the top of the food chain in wetland habitats, great blue herons are relatively long-lived. They are good indicators of environmental quality, including wetland health, the presence of pollutants, and disturbance from human infrastructure and behavior. Avid fish eaters, herons also use their long, sharp beaks to strike at frogs, snakes, insects and invertebrates, and even small mammals. They nest in colonies, often in clusters of trees in beaver flowages that may contain hundreds of nests. A female heron typically lays from three to seven eggs in a platform stick nest, and multiple nesting pairs may share the same tree. Both male and female herons help to raise the young.
Maine Department of Inland Fisheries and Wildlife biologist Danielle D’Auria first launched a citizen science adopt-a-colony program in 2009 to monitor nesting activity statewide, addressing increasing concern about dwindling numbers of herons in the state – most drastically on coastal islands (from 1,203 pairs in 1983 to only 211 pairs in 2018). To gather more detailed information on individual movements, in 2016 she initiated the Heron Tracking Project in partnership with Lenoir-Rhyne University researcher John Brzorad, and with financial support from the Maine Outdoor Heritage Fund. At the core of the project is a commitment to share discoveries with students and others interested in great blue heron behavior and habitat needs. Students from elementary and high schools involved with the project help catch bait fish for luring herons to a capture location, and some students have been able to observe biologists tag and measure the herons that they subsequently followed during migration, tracking data online in their classrooms.
“Using cutting-edge technology, we’ve engaged students of all ages in every phase of the project, within Maine and beyond. We have a teacher in Haiti who is now collaborating to teach her students about birds,” said D’Auria. “Teachers work with the students to help them – and us – answer questions about habitat use, migration routes, nesting and wintering locations, and other information that helps solve the mysteries of heron behavior.”
Project data show all the tagged herons have flown north around the same time each spring. But in the fall, timing has varied by individual, with each lingering to rest and feed in various locations as they make their way to their winter habitat. D’Auria finds all the information fascinating, and it often leads her to new questions rather than answers.
For example, “this year, Cornelia’s movement indicates she had a failed nest, and she seems to be scoping out a new colony in New Gloucester,” said D’Auria. “The big question in my mind is what is she going to do next year? Over time we’d like to get an idea of how often herons switch colonies.”
Covid-19 interrupted plans to work with schools in 2020. D’Auria hopes the new transmitter they received in 2019 to fit one more heron won’t be old technology by the time they can get back to work with students. “Technology changes so fast,” she said. “Two of our oldest units that are still transmitting are not completely compatible with the new 5G cell technology and don’t always transmit data the way they were designed to.”
All data gathered by biologists, students, and volunteers can guide future wildlife management decisions. However, tracking projects are expensive and require continuous funding. One innovative way researchers have raised funds is through the Maine Birder Band. For a small donation, supporters receive a band with a unique ID that is registered to them. They attach the band to something valuable like their binoculars or camera; if that item is ever lost the finder can call the phone number on the band to help return the found item.
Follow the Heron Tracking Project Online
Anyone can go online to track the birds and to find resources developed for educators. The herons’ transmitters download data every 24 hours to an open source website called Movebank. The data can be easily pulled into Google Earth, Excel, and ArcGIS, and people can follow the herons on their smartphone. To learn more, including how to view and download the tagged herons’ data, visit MDIFW’s tracking instructions here. Or, check out the Heron Observation Network of Maine’s Facebook page for updates on the birds’ whereabouts.
The Maine Birder Band supports this project and other bird conservation work in Maine. You can learn more here.
For more about Harper, see this story written last year by Mia, now a fifth-grade student in Maine, who participated in tagging Harper in 2019.
The sound of the great blue heron seems as ancient as its appearance; you can hear a variety of calls here.