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Some Diving Notes on Cormorants

C. I. Clay

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On June 12, 1910, while collecting along a stretch of rocky coast line in a twenty foot skiff, with Joe Francisco, my boatman, I took some interesting notes on the diving of the Brandt Cormorant (Phalacrocorax penicillatus), and Baird Cormorant (Phalacrocorax pelagicus resplendens).

We were one and one-half miles southwest from Trinidad, Humboldt County, California, and about one-half mile off shore. Mr. Francisco had set a net the night before, near a blind rock and in twenty fathoms of water. We were taking in the net when a Brandt Cormorant came to the surface in its meshes, then a second one and a third. Although the Baird Cormorants were common everywhere on the ocean, there were none in the net. On closely questioning the fisherman, he informed me Brandt Cormorants were caught almost daily in from five to thirty fathoms of water, while using the deep water nets, but were never taken in over forty fathoms of water; while the Baird Cormorant, (I had taught him the difference between the two species), were often taken in as much as eighty fathoms of water.

I saw several Baird Cormorants rise to the surface of the water with pieces of kelp in their bills, in places where Joe informed me the water was over eighty fathoms deep. Brandt Cormorants were not seen far off shore, though they were common amongst the rocks near shore. Is it a superiority in diving, or a desire to obtain a certain kind of food that prompts the Baird Cormorants to go down deeper than Brandt Cormorants, while on their feeding grounds?

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