ABSTRACT
When a flightless cormorant (Nannopterum harrisi) returns from fishing to relieve his mate from brooding, he approaches with a present: a beakful of seaweed, a small stick, or a piece of sea fan. Bowing and uttering calls, he approaches and passes the present on to his mate, who grabs it, often with a fierce movement, and adds the material to their nest. Only then will she allow the mate to stay and eventually take over the nest. Most observers of this event will intuitively be inclined to call this opening act of the relieving ritual a “greeting” and, indeed, functionally it is one; the ceremony of the cormorant serves to appease the partner. The tameness of these endemic Galápagos birds allows one to experiment; you can rob the oncomer of his present. He will act startled, but will continue after some hesitation on his way to the nest, evidently not realizing what has happened to him. But when, upon his arrival, his mate attacks him, he will retreat and search for a new present. When he finally returns with some little branch or some other object, he will be accepted by his mate (Eibl-Eibesfeldt, 1965).
