A number of recent studies have reported how budgerigars （Melopsittacus undulatus ） are capable of mimicking variousbehaviors, and that individual vocalizations are strongly influenced by those of other conspecific birds in their vicinity. Weexamined this effect by placing four budgerigars in separate cages adjacent to each other, and then recording and analyzing allof their vocalizations over a two-week period. Time-based comparisons of the amount of time spent performing warble-songsover a 10 min period revealed a strong correlation between the duration of vocalization when all of the animals were males.However, no such correlation was observed when groups consisted of two males and two females. In the male-only group,whenever one male sang, the others would join in and singing would be synchronized. We repeatedly observed synchronizedvocalizations where all of the birds sang together in what could be described as a chorus. While we were unable todemonstrate the functional significance of this behavior, since budgerigars are flocking birds, these synchronized vocalizationswere not considered to function as territorial calls or for courtship
