The Form and Duration of the Display Actions of the Goldeneye (Bucephala Clangula)

Abstract

1. The display actions of the Goldeneve (Bucephala clangula) have been analyzed from motion picture film. A name was given for each movement and the durations were measured. A record is also given of the probable order of the appearance of the actions during the spring. 2. The display actions are divided into two categories. The first includes all actions seen as F l o c k D i s p l a y s. These displays include 12 male actions and 5 female actions. The second category, P r e c o p u l a t o r Actions and C o p u l a t i o n, includes 9 male actions and 2 female actions. 3. The analysis of the display movements of the Goldeneye has shown that each is a stereotyped action. In most cases the duration of the movement has proven to be the most accurate measurement of this rigidity, however, the form of each movement has also been studied. The advantage in studying durations is that they can be easily and objectively measured, whereas no objective method of analyzing form has yet been found. 4. Some movements were found to be exceedingly constant in both form and duration. In contrast others, although constant in form, vary in duration. Even more interesting is the fact that very similar actions may be split into two types; some on the basis of form, and others on the basis of duration. 5. In contrast to virtually all of the other display actions in this species, some of the actions of the female are quite variable in both form and duration. There is the possibility that these movements cannot be clearly separated and classified.