All Hands Ecology (ACR) has been monitoring nesting Great Blue Herons (Ardea herodias), Great Egrets (Ardea alba) and Snowy Egrets (Egretta thula) in Picher Canyon since 1967. This colony is located at the Martin Griffin Preserve, on the northeast side of the Bolinas Lagoon, near Bolinas, CA (Figure 1). ACR has also been monitoring nesting herons and egrets at the Bolinas colony site, at the base of the Francisco Mesa adjacent to the Bolinas Channel since 1990. This colony’s subsite, located on the south end of Kent Island at the mouth of Bolinas Lagoon, has also been monitored by ACR since it was founded in 2008.

Los biólogos del ACR recopilan datos sobre: (1) el número de nidos activos, (2) el éxito reproductor (tasas de supervivencia de los nidos y número de pollos nacidos de nidos exitosos), (3) la etapa de nidificación (una medida del calendario estacional), y (4) cualquier perturbación observada o depredadores potenciales observados o inferidos en las proximidades del lugar de nidificación. Las tablas incluidas en este informe contienen diversas variables extraídas de los datos que se recogen cada año.