Common Loon Population Declines Across Canada

Research finds declining loon productivity and population, with lead tackle and climate change cited as key pressures.

Updated on Nov. 10, 2026 in Environmental

Photograph of a single common loon floating on dark, still northern lake water at dawn, with granite shoreline and spruce trees behind and a lead fishing sinker on a rock in the foreground. — Research finds common loon populations declining across most of their range, with Canada home to 94 per cent of breeding pairs and Ontario's population down 45 per cent since 1981. AI Illustration. Upload story photo >

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Research shows the common loon population is declining across most analyzed regions, with Canada home to 94 per cent of breeding pairs. Declines of around 40 per cent were recorded in 10 of 12 regions, and Ontario's loon population fell 45 per cent between 1981 and 2023.

Why it matters

Lead in the loon ecosystem and climate change are identified as primary drivers of the decline, and Canada's large share of breeding pairs makes its trends significant for the species overall. The findings point to the health of lakes and fish populations that loons depend on.

Research on common loon breeding regions reports a decrease of around 40 per cent across 10 of 12 analyzed regions, with Ontario's population down 45 per cent from 1981 to 2023. The extent to which lead and climate change each contribute to these declines is not resolved in the available findings.

The details

Lead tackle used in fishing is the primary cause of mortality for adult loons, and lead in the loon ecosystem is a main driver of the decline alongside climate change. Lakes contaminated with acid and metals historically had no successful loon populations, as loons depend on healthy fish populations.

1981: Start of the Ontario common loon decline period studied.
2023: End of the Ontario common loon decline period studied.

Roadmap

Sudbury's lakes once had no successful loon populations because of acid and metal contamination, showing how contamination can remove loons from a lake entirely. The current national decline follows a similar pattern, with lead in the ecosystem identified as a primary driver alongside climate change.

Anglers can avoid lead tackle, since its use is the primary cause of adult loon mortality. Lakeshore property owners can maintain native vegetation and prevent erosion, which helps protect water quality and loon habitat.

The takeaway

Protecting loon populations depends on reducing lead in fishing gear and keeping lakes healthy enough to support the fish loons rely on. Small changes at the lakeshore and in fishing habits can help reduce pressure on the species.