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Least Bittern

Ixobrychus exilis

Please note: The Canadian population of least bitterns is estimated at less than 1000 pairs. The majority of least bitterns that breed in Canada are found in Ontario.

COSEWIC Status: Threatened

COSSARO Status: Threatened

Committee on the Status of Endangered Wildlife in Canada

The committee on the Status of Endangered Wildlife in Canada is a committee of experts who determine the national status of native species thought to be at risk of disappearing from Canada. Members include academics, specialists, Aboriginal people or government, & biologists.

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Species at Risk Status

Threatened

This species is likely to become endangered if limiting factors are not reversed.

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Committee on the Status of Species at Risk in Ontario

The committee on the Status of Species at Risk in Ontario reviews the COSEWIC status reports for species that occur in Ontario, then makes recommendations on the appropriate provincial status of the species. Provincial status is identified on the Ministry of the Environment, Conservation and Parks Species at Risk in Ontario (SARO) List.

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Species at Risk Status

Threatened

This species is likely to become endangered if limiting factors are not reversed.

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Credit: Benoit Jobin

Have you seen this species at risk? Report your sighting.

Habits and Reproduction

• Often seen at the base of cattails at the edge of the water.
• Holds a still, reed-like pose at the water’s edge while waiting for the approach of fish and other prey.
• Builds its nest on a clump of marsh vegetation barely above water level.
• Clutch size varies from 2 to 6 (usually 4 or 5) bluish- or greenish-white eggs.
• Thought that least bitterns can have two broods in one season.

Habitat

• Large (5+ha) quiet freshwater marshes with dense tall aquatic vegetation, usually cattails, interspersed with clumps of woody vegetation and open water.

Threats

• Loss of wetlands, for example 90% of wetlands in south western Ontario are gone.
• Disturbance of nest areas by activities such as boating.
• Collision with cars and electric power lines.
• Migratory hazards, such as severe weather.

Conservation Actions

• Support the protection of wetlands.
• Avoid wetland areas with your motor boat or if you must travel near wetlands, reduce speed so that no wake is produced.

Thanks to the official sponsors of the Ontario Breeding Bird Atlas (Bird Studies Canada, Canadian Wildlife Service, Federation of Ontario Naturalists, Ontario Field Ornithologists, and Ontario Ministry of Natural Resources) for supplying Atlas data, and to the thousands of volunteer participants who gathered data for the project.