This report describes the results of the population inventory and monitoring of Great Blue Heron on Vancouver Island (Region 1) for 2006. During the 2006 breeding season, the British Columbia Ministry of Environment inventoried Pacific Great Blue Heron (Herodias ardea fannini) nest sites on Vancouver Island. Most of this work was conducted between March and September by Ministry staff, BC Conservation Corps, TimberWest and volunteers from the public. Data was collected from 70 sites, 14 of which had not been documented previously. In total, 609 nests, including 548 active nests, were documented in 36 active colonies. There was no significant difference in the number of active nests each year on Vancouver Island from 1997 to 2006. In 2006, of the colonies with known success, 29% failed (9 of 31), with at least 6 failures due to predation by Bald Eagles. All failed colonies, including those predated by Bald Eagles were small (≤ 3 nests). In addition to overall colony success, we monitored productivity at 67 nests sites selected for visibility. These 67 nests fledged 99 young, yielding an average productivity of 1.48 fledglings per sampled nest. The continuing low productivity and high rates of colony failure suggest future population declines. Management issues, including housing developments and tree cutting, are ongoing concerns in this fast-urbanizing area. The low productivity, especially in the northern part of their range, combined with the development pressures, makes Great Blue Herons a priority for ongoing protection and monitoring.
Chatwin, Trudy, Lana Cortese, Ruth Joy. 2007. Pacific Great Blue Heron Population and Monitoring Vancouver Island and the Gulf Islands 2006. Ministry of Environment. Wildlife Working Report. WR 118