Green Rock

Green Rock is one of the major sea-bird rookeries in California, with nine breeding species recorded. The common murre, Uria aalge, colony here is the densest in the State, with up to 10,000 pairs breeding. Other species in the rookery include Cassin's auklet, Ptychoramphus aleuticus (see Farallon Islands), tufted puffin, Lunda cirrhata, pigeon guillemot, Cepphus columba, Western gull, Larus occidentalis, black oystercatcher, Haematopus bachmani, fork-tailed petrel, Oceanodroma furcata, Brandt's cormorant, Phalacrocorax penicillatus, and the pelagic cormorant, Phalacrocorax pelagicus .

The rock is of the Franciscan formation and there is a pocket of deep soil, necessary for the burrow nests of petrels and auklets.

Vegetation is sparse, save for a thick stand of Polypodium sp. on the eastern cliffs, and consists of Synthyris reniformis, Lasthenia sp., Rumex sp., Bromus sp., Distichlis spicata, and others.

Integrity: Lying some 600 meters (2,000 feet) offshore, the rock is undisturbed save for occasional fishermen in the vicinity. It has been proposed as part of a Federal wildlife refuge.

Use: Research, educational, observational.

Ref: Osborne, T. O., 1972. Ecology and Avian Use of the Coastal Rocks of Northern California. Unpub. M.A. Thesis, Humboldt State University, 215 pp.

July 1977