Facilitating the protection and restoration of species and ecosystems at risk on BC’s South Coast

Measuring Nesting Productivity at Pacific Great Blue Heron Colonies

Most of the 6,000 to 12,000 Pacific Great Blue Herons occur in south-coastal British Columbia and north-coastal Washington State (Butler 1997, Gebauer and Moul 2001). Primary threats to the Pacific Great Blue Heron are from Bald Eagle (Haliaeetus leucocephalus) depredation, habitat loss, and human disturbance (Norman et al. 1989, Butler 1997, Gebauer and Moul 2001, Butler and Vennesland 2000, Vennesland 2000, Vennesland and Butler 2004). In Canada, the Pacific Great Blue Heron has been listed as a subspecies of ‘Special Concern’ by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC 2001) because of its specialized nesting habitat requirements, threats to its’ nesting colonies from humans and Bald Eagles, and population declines on Breeding Bird Surveys from 1966 to 1994 (Downes and Collins 1996, Butler 1997). For the same reasons, in British Columbia the Great Blue Heron has been Bluelisted (considered ‘vulnerable’) (CDC 2003), and in Washington State has been placed on the Washington Department of Fish and Wildlife Priority Habitats and Species list.

The purpose of this document is to summarize relevant background information on the Pacific Great Blue Heron and outline a standard survey protocol for the documentation of reproductive productivity at Pacific Great Blue Heron colonies in British Columbia and Washington State. This protocol will assist in ensuring consistent data collection within and among regions.



For the most up to date information regarding guidelines and regulatory requirements for various species and ecological communities at risk in BC, please contact the relevant staff with the Province of BC, Environment Canada, Pacific Region or the Species at Risk Program of the Ecosystems Management Branch, Department of Fisheries & Oceans Canada, Pacific Region. Detailed contact information can be found on our CONTACT page. 


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