Maine refuge practices sound science to study seabirds
Off of Maine’s rocky coast, you can find a network of more than 50 islands and coastal lands that are part of the Maine Coastal Islands National Wildlife Refuge. With a primary focus of managing and restoring nesting seabird colonies, the refuge has worked with partners to gather valuable information about these birds. Hear from Refuge Manager Beth Goettel about how she and her staff are working to study a number of seabird species, some of which breed nowhere else in the U.S.
Maine Coastal Islands National Wildlife Refuge has long been involved in seabird restoration and management of nesting colonies, in partnership with the Maine Department of Inland Fisheries and Wildlife, National Audubon Society’s Project Puffin, and several universities. The resulting long-term monitoring data has been valuable in understanding a great deal about these birds when they are on their nesting colony islands, but we know little about where they go to forage or their migration routes. In addition, the long-term monitoring data has provided evidence of ecosystem changes possibly due to climate change, as adult terns have been seen delivering southern fish species, which have not been seen before in the Gulf of Maine, to their chicks. In some years, herring disappear and chicks starve, a relatively new phenomenon. Our biologists have been networking with oceanographers and fisheries biologists to try to explain some of these findings.
The birds face some additional challenges. The coastline of Maine has been ranked as an excellent or outstanding wind resource area by the Department of Energy and the State of Maine hopes to establish large arrays of near and offshore turbines by 2020. We have been collaborating with partners to gather the data necessary to assist in guiding future offshore development so as to reduce potential impacts to sensitive habitats and species.
Seabird studies and the results
To learn more about the foraging habits and important foraging locations of seabirds, we have used small data loggers of various kinds. In one study, biologists attached temperature depth recorders to the bands on the legs puffins to study their feeding habits. This research revealed that puffins average 276 dives per day, and that most dives were less than 15 meters, although they occasionally go as deep as 40 meters. Puffins usually foraged within 25 kilometers of the nesting area. The surface water temperatures recorded were correlated with the sea surface temperature data from satellites to give biologists an idea of where the puffins could have been foraging on a given day.
More recently, light nanotags have been placed on common and Arctic terns and guillemots. Receivers placed on several islands near the nesting island were able to pick up the signals of individual birds as they flew nearby, allowing the biologists to learn a great deal about how long birds were on nests, how often they left, and how long they were gone on foraging flights. In addition, we have data on ground-based observations documenting the flight direction of foraging seabirds, and boats have followed birds and found some feeding hotspots. Observers on whale-watching boats have documented the abundance and diversity of seabirds using different areas.
Greater shearwaters, which breed off of Africa in our winter but feed here in the summer, are bigger seabirds which can carry more weight. Their behavior and movements likely represent foraging hotspots used by other seabirds. We have fitted these birds with global position system tags with batteries that last for several months. The data is collected via satellite, allowing the tagged birds’ movements to be watched in real time. This gives researchers a better understanding of the birds’ global migratory path and stopover areas.
Arctic terns have been fitted with lightweight geolocators to track their migration routes in the Gulf of Maine and beyond. Once a bird is recaptured the following year, and the device recovered and downloaded, the data collected throughout the previous year shows the migration path of that bird. This has shown that Arctic terns, on average, travel almost 30,000 kilometers in 92 days in their fall migration to Antarctica and almost 17,000 kilometers in 30 days on their return trip. It also showed several areas where they concentrate to feed during migration and the winter.
Bat and songbird monitoring
Refuge staff are also involved in the songbird and bat monitoring, through the University of Maine-led Northeast Regional Migration Monitoring Network. The refuge, the University of Maine, Acadia University and Acadia National Park collaborated, using radar, acoustic monitoring, banding stations, isotope analysis, nanotags and receivers to try to document and understand more about bird and bat spring and fall use of Maine’s coast. Collectively, the partners have banded nearly 30,000 songbirds of 130 species in the last 6 years, and are continuing to analyze what the data shows about broad-scale movements, movements of individual birds, food availability, and habitat use.
Recognized for scientific excellence
The staff at the refuge recently received the Rachel Carson Award for Scientific Excellence, awarded by the Service to one individual and one group each year. The award recognizes the refuge’s biologists and support staff for their extensive research to understand bird and bat movements and habitat use throughout the coastal areas, islands and waters of the Gulf of Maine. Learn more