Great blue heron (fannini subspecies) COSEWIC assessement and update status report: chapter 13
Technical summary
Great Blue Heron fannini subspecies
Grand Héron de la sous-espèce fannini
Range of Occurrence in Canada: British Columbia
Extent and area information
From GIS analysis – minimum polygon around entire Canadian range
From Geographic Information System (GIS) analysis – see Figure 2
Population information
based on Christmas Bird Count (CBC) data with a 5 (lower number) or 6 (higher)-year generation time
Threats (actual or imminent threats to populations or habitats)
Primary threats are from Bald Eagle predation, human disturbance and habitat destruction. Human influences are especially acute in the lower Fraser Valley (the centre of the subspecies’ range).
Rescue effect (immigration from an outside source)
Quantitative analysis
n/a
Current status
Committee on the Status of Endangered Wildlife in Canada (COSEWIC): Special Concern (1997 and 2008)
Status and reasons for designation
Reasons for Designation: In Canada, this subspecies is distributed along the coast of British Columbia with a relatively small population that is concentrated at a few breeding colonies in southern British Columbia. There is evidence of declines in productivity and it is unclear whether the population is stable or declining. Threats from eagle predation, habitat loss and human disturbance are ongoing, particularly in the southern part of the range where concentrations of birds are highest.
Applicability of criteria
Criterion A (Declining Total Population): Not applicable. Does not meet criterion.
Criterion B (Small Distribution, and Decline or Fluctuation): Not applicable. Does not meet criterion.
Criterion C (Small Total Population Size and Decline): May meet Threatened C1 if Christmas Bird Count trends are used to predict future declines.
Criterion D (Very Small Population or Restricted Distribution): Not applicable. Does not meet criterion.
Criterion E (Quantitative Analysis): None.
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