Annotated Atlas and Implications for the Conservation of Heron and Egret Nesting Colonies in the San Francisco Bay Area

The Heron and Egret Atlas is the result of ACR's continuing commitment to the protection of nesting herons and egrets in our region. ACR's Martin Griffin Preserve was established in 1962 to protect an important heronry on Bolinas Lagoon. In 1967, ACR began its ongoing study of the herons and egrets that nest there, and in 1990 we expanded our scientific efforts to include heronries throughout the Bay Area.

The result of our research is an atlas that covers an area of nearly 14,000 square kilometers. The data include most of Marin, Sonoma, Napa, Solano, Contra Costa, and San Francisco, Alameda, Santa Clara and San Mateo counties and extends from the outer Pacific Coast to the Central Valley of California in the north to the Santa Clara Valley and interior East Bay subregions in the south.

Sharing our findings

This work evaluates the regional status, trends, distribution and reproductive performance of herons and egrets, as well as habitat values and conservation concerns. The Atlas includes individual accounts of all known heronries in the region (over 150 sites) based on field studies conducted by Audubon Canyon Ranch and the San Francisco Bay Bird Observatory (you can also view the heronries in Google Earth). Numerous photographs by Philip Loring Greene illustrate the report.

All the Atlas files are hi-res pdfs and will require Acrobat Reader.

Download the Atlas by section:

  1. Contents and Acknowledgements (568Kb)
  2. Regional Analysis (1Mb)
  3. Colony Site Accounts Introduction (5.1Mb)
  4. Russian River Laguna de SR (4.1Mb)
  5. Northern Napa County (2.8Mb)
  6. Outer Pacific Coast (4.8Mb)
  7. San Pablo Bay (6.7Mb)
  8. Suisun Bay (5.5Mb)
  9. Central SF Bay (2.7Mb)
  10. Interior East Bay (2.2Mb)
  11. South SF Bay (5.4Mb)
  12. Santa Clara Valley (3.5Mb)

Or download the entire Atlas in one file:

To purchase a hard copy of the Heron and Egret Atlas, visit

To request a CD of the Atlas by mail, contact [email protected].

To request GIS data (heronry locations and recommended buffer zones), contact [email protected].