Decades-long study shows decline in loon chicks in Ontario

Elianna Lev
·3-min read
A loon and its chick make their way across Pierce Pond near N. New Portland, Maine, Aug. 1, 2006.  Maine's loon population has approximately 4,000 adults and 400 chicks. The 2006 census totals will be available later this fall. Maine has the largest loon population in New England and for over two decades the Maine Audubon Society has conducted a statewide counting process to keep records on the popular birds. The loons' ruby red eyes aids them in their underwater vision when fishing for food.  The birds migrate to open water by the ocean, just before the lakes freeze over later in the fall season. Loons can live between 25-30 years. (AP Photo/Pat Wellenbach)
A loon and its chick make their way across Pierce Pond near N. New Portland, Maine, Aug. 1, 2006. (AP Photo/Pat Wellenbach)

The call of the loon is the unofficial soundtrack to summer at the cottage in many parts of Canada. But lakes might get a lot quieter according to research, which shows that loon chicks are in decline and could signal to larger environmental issues.

For nearly 40 years, citizen scientist volunteers have collected data from loon populations around lakes across Ontario. The data is being examined by post-doctoral researcher Kristin Bianchini, Arcadia University and Birds Canada, to understand what factors could be impacting the number of chicks that loons have been producing over time.

“We found that the number of loon chicks have been declining for the past four decades,” Bianchini tells Yahoo Canada. “It’s probably related to an interplay between acid rain, mercury pollution and climate change.”

Sources like the Ministry of Natural Resources were able to provide the data on environmental statistics like pH balance and mercury, which Bianchini then analyzes. The research around the loon’s activities relies on data collected from cottagers, residents and “anyone who has access to a lake in the summer” from over 1,500 lakes across Ontario. The data has been collected every year since 1981.

The volunteers are required to examine the lake at least three times a year: once in May when pairs of loons first appear, then again in June to see if the birds have produced chicks and finally in August, to report whether the chicks have made it to about six weeks old. At that age, they are considered “the large young,” Bianchini explains. That means they’re less vulnerable to predators and indicate the loon pair has produced chicks that will successfully make it to adulthood.

What the study has found is that the number of chicks loons are averaging has fallen. In the 1980s, loons would produce .8 chicks per pair per year, compared to now, which is .6 per pair per year. Bianchini says while it doesn’t sound like a big decline, other studies suggest that if the rate falls below .48 chicks per pair per year, the number of adults would decrease in the loon population. And that could mean bigger problems on a larger scale.

“Loon chicks are a good indication of what’s happening with the lake's health,” says Bianchini.

Chicks rely solely on fish from the lake in order to survive. If there’s a decline in the number of fish or what the fish are eating that causes that decline, it will be reflected in the number of chicks that are raised. Changes in the number of chicks can also reflect changes in the number of adults.

“It helps us to see what’s happening to loon populations,” she says.

Loons are found all across Canada and in the northern United States. When they migrate in the winter, they can also be found on the ocean.

A 2013 study conducted by Dr. Doug Toser that looked at the number of loon chicks in southern Canada found similar declining trends, which related to pH. However, the decline in loon chicks are steeper in eastern Canada than western Canada.

Bianchini says lake-goers can help keep loon chick populations up by minimizing waste when boating, keeping shorelines clean and maintaining the native vegetation along shorelines to help protect the birds’ habitat.

Any lake-goers wishing to participate in the research can take part by visiting the Birds Canada website.