The Great Blue Heron is the largest member of its family in North America, and is known for patiently moving through shallow water before striking with incredible speed to snatch fish, frogs, snakes, or even small mammals and birds. It has specific feathers that break down into powder; these are applied through its feathers with a comb-like claw to help keep them clean.


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The Great Blue Heron is the most widely distributed heron in Canada, breeding from British Columbia to Nova Scotia, and wintering from southern British Columbia and the southern Maritimes through the United States, Mexico, Central America, and the Caribbean. There are approximately 77,000 individuals in Canada, representing 11% of the global population and a low degree of responsibility for Canada. The Breeding Bird Survey indicates that the national population has undergone little change relative to 1970 and there is high confidence in this assessment based on the survey's coverage and precision.
The resident population along coastal British Columbia, classified as the fannini subspecies, was designated as Special Concern by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in 1997 and again in 2008 because of its small numbers (COSEWIC, 2008), declining productivity, and uncertain trends. A reassessment by COSEWIC in 2023 concluded that the population is not sufficiently distinct from that in the rest of Canada to be recognized as a separate designatable unit (COSEWIC, 2023), but it remains listed as Special Concern under the Species at Risk Act. As previously defined, this population has undergone a moderate decrease relative to 1970 based on the Breeding Bird Survey and is below its goal range, but confidence in this status is only medium, as some sources show little change. The national population of Great Blue Heron is within its goal range.






The best source of information on the population status of Great Blue Heron in Canada is the Breeding Bird Survey (BBS). Although Great Blue Herons nest in colonies, they roam widely to forage and are readily observed. As such, the BBS is considered highly suitable for monitoring the species, and the survey also covers more than half of the Canadian range and has high precision, resulting in high overall reliability. The national trend shows little long-term change overall, although there was a notable increase from the early 1970s to late 1980s followed by a decline ever since, to a current level 19% below that in the early 1970s. Trends vary regionally, ranging from moderate declines of 26 to 49% along the Pacific Coast, in central parts of Ontario and Quebec, and in the Maritimes, to moderate increases of 36 to 43% in the southern Rockies and northern Prairies. The Pacific trend is corroborated by the British Columbia Coastal Waterbird Survey, which shows a trend of -16% between 1998 and 2018, but the long-term Christmas Bird Count trend for the central and northern Pacific Coast is 12%, corresponding to little change.
The national goal for Great Blue Heron is to maintain its population at or above the level it was at in the early 1970s, based on the Breeding Bird Survey. Recent data show that the population is within its goal range.
For the fannini subspecies in British Columbia, the goal is to increase the population to the level it was at in the early 1970s, based on the Breeding Bird Survey for the Canadian portion of Bird Conservation Region 5. Trend data show that this population is currently below its goal range, but it has shown a slight increase over the past decade. Analysis of recent trends and potential growth rates suggests that the fannini subspecies of Great Blue Heron could reach its population goal by 2050 with the support of conservation action.
Designation | Geographic Area | Status | CITATION | Subpopulation |
---|---|---|---|---|
COSEWIC | Canada | Special Concern | Great Blue Heron fannini subspecies | |
IUCN | Global | Least Concern | ||
Species At Risk Act | Canada | Special Concern | Great Blue Heron fannini subspecies | |
Wild Species | Canada | Secure |
- COSEWIC. 2008g. COSEWIC Assessment and Update Status Report on the Great Blue Heron fannini subspecies Ardea herodias fannini in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vii + 39 pp. https://wildlife-species.canada.ca/species-risk-registry/document/default_e.cfm?documentID=1615.
- COSEWIC. 2023d. Addendum to the 2008 COSEWIC status report on the Great Blue Heron fannini subspecies Ardea herodias fannini in Canada. https://www.canada.ca/en/environment-climate-change/services/species-risk-public-registry/cosewic-assessments-status-reports/addendum-2008-great-blue-heron-2023.html.

The Great Blue Heron is the largest member of its family in North America, and is known for patiently moving through shallow water before striking with incredible speed to snatch fish, frogs, snakes, or even small mammals and birds. It has specific feathers that break down into powder; these are applied through its feathers with a comb-like claw to help keep them clean.
Great Blue Heron is reported throughout the year in Canada, with the lowest levels of observation during the winter when many move south.

