Audubon Canyon Ranch (ACR) is a 501(c)(3) not-for-profit environmental conservation and education organization headquartered in Stinson Beach, Marin County, California, on the eastern shore of Bolinas Lagoon.

Audubon Canyon Ranch was founded in 1962 to save a major heronry and block commercial development of Bolinas Lagoon in western Marin County, leading the way for the protection of Tomales Bay to the north.

ACR's conservation science program has monitored the North Bay region nesting successes of herons and egrets for over 40 years,[2] collected long-term data sets on wintering shorebird and waterbird populations[3] on Tomales Bay for over 30 years, and is using GPS to track the movements of individual mountain lions[4] in the Sonoma Valley and Great Egrets and Long-billed Curlews on the coast.

The preserve's frontage along Bolinas Lagoon brings more than 60 species of waterbirds and shorebirds into view—from sandpipers to osprey to pelicans—as well as some of the resident harbor seals.

The History Operating for many years as a family-run dairy ranch called Canyon Ranch, the land is now protected in perpetuity thanks to the conservation efforts in the early 1960s of L. Martin Griffin[8] (then president of the Marin Chapter of the National Audubon Society), Aileen Pierson, Stan Picher, and other dedicated volunteers who organized to purchase the property for the protection of heron and egret nesting sites.