|The Heron Network||
The goal of the Heron Network program is to conserve a network of sites necessary to ensure the long-term viability of naturally occurring heron populations in British Columbia and Washington. The general objective is to identify sites that regularly hold significant numbers of herons and to encourage their protection. These sites include foraging areas and nesting sites. The approach of the Heron Network is two tiered – The first tier is to secure key foraging habitats and ensure these habitats continue to provide the needs of herons. The second tier is to ensure sufficient forested landscape remains near the foraging areas to allow herons a choice of nesting sites.
Significant sites - Many international bird conservation programs use a criterion of 1% of a population as a minimum threshold to consider a site of significance. There is no fundamental biological reason why 1% should be used as a threshold. However, around the world other countries and programs have applied the 1% threshold and found it to afford an appropriate degree of protection through the identification of ecologically sensible sites. There is an estimated 10,000 Pacific Great Blue Herons in the Pacific Northwest. Therefore, the Heron Network Program considers any foraging site that annually holds 100 or more herons to be sufficiently important to justify protection. It is important to keep in mind that 100 herons might nest in one colony of 50 pairs or in many colonies totalling 50 pairs. Therefore, significant nesting sites include all colonies regardless of their size that are a subset of a foraging flock of 100 or more herons.
Herons nest in a variety of forests in rural, residential and urban areas. Colonies are located within about 10 kilometers (16 miles) of the foraging areas. The area of the foraging area determines the number of herons that will nest in the neighbourhood. Disturbance by humans and eagles is thought to negatively impact herons. A forested buffer of 300 meters (325 yards) from the edge of a colony is recommended to limit human disturbance around colonies. Fifty pairs of herons require room to build the colony too. We assume that a circle of forest with a radius of 350 meters will provide both nesting space and a buffer of quiet habitat for 50 pairs of herons. The area of a circle with a 350 m radius is about 39 hectares (95 acres).
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