Hunting heron

Duxbury Reef is a low-relief intertidal bench at the west end of Bolinas Bay in Marin County in northern California. Tidal seaweeds and invertebrates live in a matrix of cobbles and silty sand which left the water rather murky – more like an estuary than the outer California coast. It seems like the unusual substrate of this site limits algal diversity and results in a fairly unique community. Several parallel ridges of bedrock provide some rare additional relief that hosts more typical mid-intertidal species like rockweeds and mussels.

Birds were actually the highlight of my low tide visit earlier this month to the reef. Unnerved by my presence, a great blue heron hunted in the shallow water with the rising tide. I crouched and observed for some time, witnessing at least two successful hunts of intertidal fish. The bird’s patience was obvious, but they must have remarkable eyesight to see fish which are probably well hidden in the dark tidepools.