One afternoon in early fall I heard a bird making a ruckus on Little Medicine Lake (Siskiyou County CA). Being a visual, not an aural person, I have a difficult time identifying bird calls. (Leonard, much more capable in that area, was not with me.) So off I went to explore the source of the “noise”.
A lone juvenile double-crested cormorant (Phalacrocorax auritus) was continuously calling while swimming on Little Medicine Lake. I watched the cormorant swim and make its deep, guttural grunts non-stop for at least fifteen minutes. I finally left the bird swimming and calling. Double-crested cormorants vocalize on taking off or landing, during mating or as an aggressive gesture. This juvenile was calmly swimming around without any other bird or animal in the area. I have no explanation for its behavior. Later I returned and the cormorant was placidly standing in the shallow water.
Adult double-crested cormorants are uniformly black while juveniles are more brownish and pale brown to buff or even white on the neck and breast. The belly is darker brown.
Double-crested cormorants nest in colonies. The male brings sticks and other debris to the female who does the actual nest construction. The nest is of platform design and lined with grass and is built on rocky cliffs near water, on the ground on an island or in a tree near water. As the nesting season progresses, the sticks and trash making up the nest become cemented together by bird droppings.
The 3 to 5 pale blue-green, unmarked eggs are incubated for 25 to 28 days. The atricial (born helpless) chicks remain in the nest for 21 to 28 days while both parents feed them regurgitated food – fish, insects, amphibians and crustaceans. When the youngsters leave the nest they roam around with other colony young, returning to the nest to be fed by the parents. After about ten weeks the juveniles are totally independent of their parents.
I could not find a clue as to where this juvenile cormorant was raised – no nearby colony or other cormorants were visible.
The name cormorant comes through French from the Latin “corvus marinus” meaning “sea crow”.
More information about the double-crested cormorant can be found in my earlier post, “Double-crested Cormorant”.