Budgerigars use contact calls and warble-songs. Previous studies have found that they acquire these songs through vocallearning, but to date, there have been no long term experimental studies of their vocalizations or social interactions. Thepurpose of this study was to establish a basic understanding of budgerigar vocal ethnology. We recorded all sounds made byfour budgerigars (male=4, female=3) kept in separate cages in a same experimental box for fixed periods (12-h light/darkcycle). There was great diurnal variation in vocalizations, but the variation decreased from lights up to off and during thelights-off period. The variation in vocalizations was also positively related to changes in humidity. The frequency of soundsproduced by the group of males was higher than that of the group of males and females mixed together. The response rate forcontact call varied among individuals which suggests that hierarchy existed in vocal communication. However, the hierarchychanged depending on the membership in a group.