EFFECTS OF PAIR BOND AND PRESENCE OF CONSPECIFICS ON SINGING IN CAPTIVE ZEBRA FINCHES

Undirected Song is commonly performed in wild and captive zebra finche s and is typically given by males partly isolated from other members o f the flock or colony. It has no territorial function nor it is used d uring precoital courtship; its frequency varies strongly among individ uals. However, its rate of performance is severely limited by the clos e proximity of conspecifics, and this study investigated what social f actors are responsible for this constraint in first-generation offspri ng of wild-caught zebra finches. The close presence of females caused a greater reduction in singing than did that of males. Familiarity bet ween companions and the singer was also a factor that reduced the rate of singing. The more familiar the singer became with a female the mor e often he would sing in her presence, whereas the opposite occurred w ith males - singing was more prevalent with strangers than with famili ar companions. Pair formation reduced a singer's sensitivity to inhibi tory factors associated with the close proximity of conspecifics. Simp le visual and auditory contact with a conspecific was not sufficient t o constrain Undirected Singing, but intense, close range interactions appear to be necessary. It is hypothesised that Undirected Singing is used to attract females for pair formation or extra-pair mating, but t he close proximity of male companions and/or the mate hampers this. Ho wever, in a competitive mate choice experiment there was no significan t correlation between the rate at which a male gave Undirected Song an d order of the pair formation. This suggests that Undirected Singing m ay nor be crucial in the ultimate choice of a mate, but it may still b e a useful cue at the outset of pair formation.