As twilight descends during the summer, a haunting call fills the air, creating an eerie stillness over the calm waters of wetlands and lakes throughout Canada.
However, recent research indicates that the distinctive call of the common loon may be becoming less frequent due to “substantial” declines in North American populations, particularly among those in the Prairie and Atlantic regions, which are experiencing some of the most significant reductions.
Matthew Fuirst, an ecologist with Birds Canada and a co-author of a study released on Thursday in the journal FACETS, stated, “What’s most concerning is the magnitude of this decline.”
Canada boasts 94 percent of the world’s common loon population, with around 254,000 breeding pairs (approximately half a million individuals) that migrate north every spring to raise their young.
This iconic bird, which many Canadians carry as a symbol in their pockets and purses, has faced various threats over the years, including DDT, lead-based fishing gear, and mercury pollution.
In this 1971 CBC archive story, former reporter Howard Sommerville investigates how DDT impacted Canadian loon eggs.
Currently, a new group of nearly twenty collaborators from Canada and the U.S. is identifying climate change as a potential factor contributing to declines in loon chick populations.
The study examines loon breeding data from approximately 3,421 lakes over the last three decades, with half of the data sourced from thousands of volunteer observations as part of the ongoing citizen science project known as the Canadian Lakes Loon Survey.
The findings revealed “significant declines” in the number of chicks observed in most regions during this period.
Researchers analyzed data from nearly 46,000 breeding loon pairs on specific lakes where eggs or newborn chicks were observed, but there were no sightings of six-week-old chicks. This served as the benchmark for their loon chick productivity rate.
The analysis indicates an average decrease of 40 percent in loon chick productivity across 10 of the 12 study areas, including British Columbia and Ontario, over the past thirty years.
A map illustrating the breeding range of the common loon in North America, featured in the recent FACETS journal article documenting declines in loon populations. (FACETS journal)
In Alberta, Saskatchewan, and Manitoba, loon chick productivity has plummeted by 65 percent since the early 1990s. In contrast, the East Coast of Canada has seen a dramatic 74 percent drop, according to the research findings.
The only regions where chick productivity appeared to remain relatively stable were Quebec and Maine.
The research team points out that while loon chick numbers are not the sole indicator of population health or stability, these long-term reductions could “indicate potential population declines” in the Prairies, Ontario, Atlantic Canada, and states like New York, Massachusetts, and New Hampshire.
Nicola Koper, dean of the faculty of environment at the University of Northern British Columbia and not involved in the study, remarked, “This study’s design is robust, and frankly, I find the results they present to be alarming.”
Koper, who co-authored Best Places to Bird in the Prairies, spent nearly twenty years as a professor of conservation biology at the University of Manitoba before moving to UNBC.
She noted that while the declines are significant on their own, the fact that they have occurred within just three decades is particularly startling.
“Some readers may be 30 years old, and if they reflect on whether they remember seeing more loons with chicks when they were younger, there’s a good chance that feeling is correct, as they might have witnessed this change themselves,” Koper added.
Climate change as a contributing factor
The research team indicates that the reasons behind these declines may differ by region, and this is an area they are currently investigating, according to Fuirst.
However, in all instances, these losses are driven by human activity.
Fuirst stated, “Human development, shoreline construction, and environmental pollutants associated with climate change pose additional threats we are facing.”
“As climate change alters weather patterns, acidic rainfall impacts lake acidity, consequently diminishing fish availability for loons.”
A baby common loon rests on its parent’s back in northwestern Ontario in July 2026. (Bryce Hoye/CBC)
The warmer temperatures associated with climate change have also led to increased rainfall and storm occurrences in loon habitats.
These conditions could potentially destroy low-lying loon nests or drown eggs during flooding events caused by rising waters or turbulent wave action, as noted by Koper.
Recent studies in the U.S. Midwest have linked poor loon health to reduced water clarity, which can result from increased sediment entering lakes due to more frequent rain.
This affects loons’ ability to see and capture their prey, including minnows and crayfish, according to Fuirst.
“It’s a chain reaction stemming from climate change that ultimately impacts water quality,” he added.
The study consolidated data from Alberta, Saskatchewan, and Manitoba into one Prairie category due to insufficient data for each region to confidently assess loon populations independently.
Koper mentioned that this may reflect the inaccessibility of many lakes in the Prairies to volunteers or their sparse populations.
Fuirst advised anglers to choose lead-free, less harmful tackle, urged boaters to avoid disturbing loons, and recommended that cottagers maintain natural shorelines.
“Every individual can take various actions to help protect lakes and the loons that depend on them,” he stated.
Koper encouraged those who are concerned by these findings to take initiative and participate in citizen science projects like the Canadian Lakes Loon Survey and to “advocate with … politicians about the significance of climate change and its effects on our wildlife and our lives.”