DOMINANCE AND DIET SELECTION IN JUNCOS

We measured the effects of dominance on diet in an aviary flock of sev en dark-eyed juncos (Junco hyemalis). Preferences among six types of f oods were recorded for each individual while solitary, and compared to that individual's diet when in the flock. Individuals specialized on different foods during the flock trial. Subordinates showed greater sh ifts in diet between the solitary and flock trials, had less diverse d iets than dominants in the flock, and reduced the proportion of their diet consisting of preferred foods to a greater extent than dominants. We interpret this change in diet by subordinates as a response to int erference competition by dominants at preferred foods.