Female Cowbird Song Perception: Evidence for Different Developmental Programs within the same Subspecies

, Female Molothrus ater from Oklahoma at the subspecies border with M.a. obscurus were tested for their discrimination of songs from their native area and from Austin, Texas. This 400-km distance is characterized by a structural shift in the male cowbird's inclusion of the mid-song element, a structure found in the songs of Austin and the more southern M.a. obscurus populations but not in the songs of Oklahoma or the more northern and eastern M.a. ater populations. Females captured in Oklahoma showed a strong preference for their native song variants. In contrast, captive females from Oklahoma who were housed with Austin males showed no preference, responding equally to Oklahoma and Austin song. The songs of the Austin males housed with the Oklahoma females did not differ acoustically from those of wild Austin males. Thus, a different developmental pattern may operate in this region than in eastern populations of M.a. ater: here, the female may be more open to social influence.