ABSTRACT
The fishes are at the bottom of the vertebrate scale. Their behavior is predominantly instinctive; and, accordingly, it seems in many cases quasi-mechanical and unintelligent, as when the fish which has escaped from the angler's hook seizes the same bait and the same hook a second time after a brief interval. This chapter draws the student's attention to one of peculiar interest. How do birds recognize the members of their own species? And how do they single out their mates, to whom so many of them remain faithful for life? Among the birds, there are three principal kinds of sense-impression by means of which the male evokes in the female the train of instinctive behavior which culminates in her submission to impregnation by him; the vocal display, the display of plumage, and the display of antics.
