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How does Minnesota know its loon population is healthy? It counts them

Keeping track of Minnesota’s state bird requires the efforts of a network of hundreds of volunteers.

Loon monitoring started after the DNR did a full loon census in 1989, using volunteers on the ground and aerial flyovers to try to count loons on every lake in Minnesota.
Photo by Kelly Sikkema on Unsplash

It was bright and early Tuesday morning when Maxine Blommer and her husband Dan climbed into a fishing boat and pushed off into the waters of Farm Island Lake near Aitkin, Minnesota.

They spent about three hours motoring along the shoreline of the 2,000-acre lake, just beyond the docks, for one express purpose: to look for loons.

The Blommers are among the thousand-or-so people across the state of Minnesota who volunteer with the Minnesota Loon Monitoring Program, an annual Department of Natural Resources-led effort to keep an eye on the health of the state bird — and Minnesota’s lakes.

Loon monitoring started after the DNR did a full loon census in 1989, using volunteers on the ground and aerial flyovers to try to count loons on every lake in Minnesota, finding about 12,000 breeding loons.

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After that census, the DNR kept the loon count going on a smaller scale, using volunteers to survey 100 lakes in each of six index areas —  Aitkin/Crow Wing, Becker, Cook/Lake Itasca, Kandiyohi and Otter Tail — across the state every year, beginning in 1994.

“If we do these monitoring surveys, we can make the assumption we probably still have about 12,000 loons in the state,” said Krista Larson, a nongame research biologist at the DNR who coordinates the loon count. Minnesota has a larger summer loon population than any state other than Alaska.

Over the years, the number of loons has remained stable in five of the six index areas, with a marginal increase in the Otter Tail area.

Adult loons counted, 1994-2017
Source: Minnesota Department of Resources Loon Monitoring Program

Different index areas have different kinds of human disturbances, like shoreline development and roads, and acid rain sensitivity, Larson said, which could all affect loons. If the loon population takes a dive in one index area and not others, it might point biologists toward one of those phenomena as the cause.

Research suggests climate change could force loons out of Minnesota by the end of the century.

map of loon regions
Source: Minnesota DNR
Minnesota’s six loon-counting regions
But for as long as the DNR’s been tracking the birds, loon populations have been stable across the index areas over time. The Itasca index area in northern Minnesota has the most loons per acre of lake, while the Kandiyohi area, in west central Minnesota, has the fewest.

Last year, Cad Lake, south of Bigfork in the Itasca region, recorded the highest concentration of adult loons per acre, with four on a 15-acre lake.

Volunteers only search lakes larger than about 10 acres, because loons, rarely found on land, need a long water runway to take off in flight and are thus found in larger lakes. Loons are also less likely to be found in shallow lakes, because shallow lakes often contain more vegetation, which makes it hard for loons to see their fish prey and dive to catch it.

Because they fish for food by sight, loons are also more likely to be found in lakes with clearer water. That makes them a good indicator species for the health of the water in lakes.

The loon stats are also used as one of the indicators in the governor’s Conservation Agenda, with the goal of maintaining 2.65 adult loons for every 100 acres of lake in the Aitkin/Crow Wing Index area, which has seen population growth. Loon populations have reached that target in all but one of the last 10 years of data.

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Life of loons

Loons are Minnesota’s state bird, but they don’t spend the whole year here. Like many Minnesotans, they’re snowbirds, flying south to their wintering grounds near the Gulf of Mexico for several months of the year.

Most Minnesotans wouldn’t recognize a loon in Florida, because their plumage changes in winter.

“They’re more drab during the winter months,”  said Kevin Kenow, a research wildlife biologist with the United States Geological Service in LaCrosse, Wisconsin.

Loons typically return north just after ice out in Minnesota lakes. The loon count happens every year around the Fourth of July weekend partly because people tend to be available to count — up at the cabin for holiday festivities. But it’s also because of loons’ biological schedule. Loon chicks are typically big enough to be seen and counted by the Fourth of July.

Loon in non-breeding plumage at Sunset Beach, North Carolina.
Loon in non-breeding plumage at Sunset Beach, North Carolina.
On Tuesday, the Blommers counted 15 adult loons and two baby loons on Farm Island Lake, where anywhere between five and 27 adult loons have been counted in the last couple decades. The lake is big, has bays, a curvy shoreline and several islands, making it a good candidate for lots of loons.

“If you have a lake that has lots of bays and inlets and the shoreline is wavy, (it tends) to be more supportive of more pairs of loons,” Larson said.

Loons are social animals in fall, when they can be found hanging out on lakes in the the hundreds, but they’re territorial when they’re breeding, and don’t like to nest where they can see other loons, she said.

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The Blommers started counting loons after Maxine saw an ad looking for volunteers in Minnesota Conservation Volunteer Magazine, a DNR publication, more than 20 years ago. At first, they camped and counted the birds on lakes in western Minnesota. Then, they bought a place near Lake Mille Lacs, and laid claim to the count on Farm Island and a smaller lake where they don’t usually see loons.

They go out to count loons early in the morning, while the lake is still.

“The earlier you get out there the better,” Maxine Blommer said.

It’s quiet, but someone occasionally spots them and asks what they’re doing.

“We tell them, and they say ‘Good for you,’” she said.

New volunteers needed

Blommer said she always loved loons, from the time she was in her 20s. Over the years, during the count, she’s learned a lot about their behavior. But this is the couple’s last year as volunteers for the program. Dan’s 85 and she’s 79, and it’s time to retire, she said.

Many volunteers love the annual ritual of counting the loons, so there isn’t much turnover, Larson said. But she anticipates a need for more help in the future as people who have done the count for many years seek to retire from it. Anyone interested in volunteering can learn more here.

On big lakes, a boat is usually needed to do the count, but on smaller lakes, loon observers can look with their bare eyes or use binoculars from land.

A donation from Minnesota United, the St. Paul soccer team whose mascot is a loon, brought in money to help the loon monitoring program build a digital map to show which lakes are in need of volunteer surveyors. Larson expects to see more openings at the beginning of the year, when the DNR touches base with volunteers to see if they’re available for the upcoming count.

Currently, volunteers fill out loon count forms by hand, but Larson hopes to have a mobile interface available before too long.

Maxine Blommer hopes that whoever takes over loon monitoring duties from her and Dan enjoys it as much as they have.

“It’s not a real hard thing to do, but it was just really fun to be a part of,” she said.