The organization of grooming in budgerigars.

Structural rules for grooming are examined in the budgerigar (Melopsittacus undulatus). Two types of bouts are found: short bouts with no predictable temporal pattern and long bouts with some degree of periodic occurrence. Transitions in long bouts are mostly based on anatomical proximity. Grooming movements cluster together according to function and body region. Evidence for hierarchical organization obtained by clustering is confirmed by the proportion of occurrence of movements in long and short bouts. Individual birds are similar enough on measures of occurrence, transition and hierarchica structure for pooling of subjects to be justified; this suggests that the organizational rules found here are to a large extent species-typical.