Oct. 15, 2011, an adult male common loon (Gavia immer) left Lake Vermilion near Ely. Dubbed V4, he had spent the summer there with his mate, nesting and raising one or two chicks. Like all loons, he traveled solo. The chicks would stay longer on their natal lake, leaving for wintering grounds in early November. V4's implanted satellite transmitter and geolocator leg band would generate data on his daily migratory movements and feeding patterns.
V4 stopped first along the southeastern shore of Lake Superior. The next day he took off for northeastern Lake Michigan. Along with thousands of other loons from Minnesota, Wisconsin, and Canada gathered in this staging area, V4 took time to fish and rest before the next legs of the journey. After a week, he flew across Michigan to Lake Huron, stopping there for just one night. On Oct. 25, the loon landed on Lake Erie and stayed for more than three weeks.
On Nov. 17, V4 left for the Atlantic coast, then crossed the Florida panhandle and set down in the Gulf of Mexico on Nov. 20. There, at the end of his 1,900-mile journey, the bird settled into his winter life along the coast.
As the ice began to melt in Minnesota, V4 again took wing, departing the Gulf of Mexico on March 24, 2012, and arriving back on Lake Vermilion April 18.
All of these discoveries and more result from the research of wildlife biologists. Although our state bird is one of the most studied avian species in North America, knowledge of its migratory behavior is surprisingly sketchy. And the hazards the birds encounter are likewise not well understood. In this issue "Flying With the Loons" tells of tracking them to untangle the food web that leads to avian botulism, as well as to investigate the consequences of oil spills in coastal waters. Whatever researchers can learn about loons can bolster plans to protect them and their many habitats.
We do know clear water is critical for loons because they are visual predators. In warm, shallow waters near shore, a loon swims with its eyes below the surface, on the lookout for prey. It watches for the quick turn of yellow perch, pumpkinseeds, bluegills, or other fish with erratic movements. In coastal waters, loons might forage as a group, pursuing schools of gulf silversides or other small fish. Geolocator data showed loons diving every five minutes to a depth of 130 feet—that is, to the bottom where oil residue and other contaminants settle.
The 2010 BP Deepwater Horizon disaster in the Gulf of Mexico prompted researchers to include Minnesota loons in an ongoing botulism study being conducted in Wisconsin. Collecting information on their wintering habits is providing valuable information on both botulism and oil contamination threats. Gulf oil spills are an ongoing problem, says Lori Naumann of the DNR Nongame Wildlife Program, and whatever happens down there is likely to affect Minnesota birds.
Also in this issue, "More Time for Trout" points out that human activity on land places pressure on our waters. While fishing regulations certainly play a role in the health of the trout fishery, nothing trumps the importance of water quality. Clear coldwater streams flow through land that holds soil in place and filters runoff.
In any waterway, the abundance and diversity of aquatic life is a strong indicator of water quality. That's why the Pollution Control Agency and the DNR do biological monitoring of streams and lakes. With fish surveys and sampling of aquatic invertebrate and plant communities, researchers assess water quality today and monitor it over the long term.
Continual monitoring often relies on citizen volunteers. A cohort of volunteers can greatly boost the amount of data collected. Volunteers with the PCA Citizen Lake-Monitoring Program gather water-transparency data, which helps scientists detect problems with water quality. The DNR has long-standing programs for volunteers to help monitor loons on more than 600 lakes, as well as opportunities to help with other wildlife surveys.
We can all support research by checking the loon on state income-tax forms or donating directly to DNR Nongame Wildlife.
Kathleen Weflen, editor