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Great Blue Heron
Ardea herodias herodias

Great Blue Heron
Great Blue Heron

    Land Tenure - Great Blue Heron
  • Body length: 1 metre; wingspan: 1.8 metres.
  • Tall, wading bird with long yellow legs and long neck.
  • Blue-grey body feathers, white head with a black stripe above each eye and long, yellow bill.
  • Adults have a white forehead and black head plumes.
  • Distinguished in flight from cranes (which are seen only in migration in the Okanagan): herons will usually curl their neck back against their body while cranes hold their neck straight out.


British Columbia Blue List

Special Significance

In British Columbia, most of the human population lives in the Great Blue Heron's natural habitat - the coast and the Southern Interior. Continuing development has destroyed valuable nesting and foraging areas. To ensure the survival of these birds, efforts should be made to protect natural habitat within 300 metres of nesting colonies. The preservation of forests near water will provide future nest sites. Herons, their nests and eggs are protected under the British Columbia Wildlife Act.


  • Found throughout southern Canada.
  • British Columbia population found along the coast and in the Southern Interior.
  • No major nesting colonies occur in the South Okanagan-Similkameen.
  • Some interior birds migrate to the coast for the winter months.


  • Heron colonies are located in groves of large trees along the banks of lakes, slow-moving rivers, sloughs, marshes and ponds in the North Okanagan.
  • Grassy fields with abundant rodent populations may be important habitat for winter survival.


  • Herons nest in colonies, or heronries; most colonies are occupied for years.
  • Stick nests are lined with twigs, rushes, bark and evergreen boughs; nest size is about 1 metre in diameter.
  • Nests are generally located in trees, 20-50 metres above the ground.
  • Pair bonding occurs from mid-February to early April.
  • Three to five eggs are laid in April or May and hatch in about 4 weeks.
  • Mortality is high for birds in their first year.
  • Oldest recorded age is 23 years.

Food Habits

  • Herons patiently wade in calm, shallow waters for fish, frogs, salamanders, snakes, large insects; also seen foraging in meadows and fields for mice and voles.
  • They use their long, powerful neck and bill to grab their prey.

Interesting Facts

  • Heronries can occupy up to 2 hectares of forest containing over 400 nests. Okanagan colonies are much smaller, usually comprising only four or five pairs.
  • Despite their tall stature, herons' average weight is just over 2 kilograms.
  • When herons catch rodents, they eat them whole. They can digest the bones, but not the fur, which is spit up in pellets.


  • Human disturbance may cause abandonment of nest colonies.
  • Extensive land development has reduced the availability of suitable nesting sites.
  • Young have a low survival rate; an estimated 70 percent perish after they have reached the flight stage.

Management Considerations

  • Human activity should not occur within 300 metres of active nest colonies.
  • Disturbance of feeding areas such as marshes, estuaries and fields should be avoided.
  • Contact your local British Columbia Ministry of Water, Land and Air Protection if a nesting colony is located.


1. Campbell, R.W., N.K. Dawe, I. McTaggart-Cowan, J. Cooper, G. Kaiser and M.C. McNall. 1990. Birds of British Columbia: Volume 1, Royal British Columbia Museum, Victoria, BC.
2. Butler, R.W. 1995. Great Blue Heron, Ardea herodias. The Birds of North America, No. 25. The American Ornithologists' Union. eds. A. Poole, P. Stettenheim and F. Gill. The Academy of Natural Sciences of Philadelphia, Washington, DC.
3. Butler, R.W. 1997. The Great Blue Heron. UBC Press.


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