Effects of hunger on aggression, approach, and avoidance by juncos (Junco hyemalis).

The aggressive tendencies of male dark-eyed juncos Junco hyemalis did not differ significantly following deprivation from food for 20 and 60 min. Tendencies to approach opponents at food, in contrast, increased with longer deprivation. Acute hunger and aggression are thus not competing behavioral systems. Nor do differences in rates of approach by subordinates affect aggressive tendencies of dominant birds.