This protocol will provide annual information on the size, distribution and productivity of heron and egret nesting colonies in the San Francisco Bay region. Colony site data will be summarized by subregion and contribute to regional estimates of nesting distribution, nest abundance, seasonal timing, and reproductive success, with an ability to detect annual changes in regional productivity of 15-20%. The following information will be obtained annually at all known heron and egret nesting colonies in the region.

1. Colony size, based on the peak number of active nests observed during multiple visits, provides an index of the number of pairs of birds attempting to breed.

2. Nest survivorship, based on focal samples of nest fates in each colony

3. Productivity of successful nests, based on prefledging brood size in completely visible broods 4-8 weeks old, for Great Blue Heron and Great Egret, and 7-15 days old for Snowy Egret and Black-crowned Night-Heron

4. Seasonal timing, based on distribution of nests across five behavioral stages

Field data will characterize individual colony sites, although additional effort will be required to monitor large colonies.