Evidence of innate vocal mimicry of host young by the brood-parasitic screaming cowbird

JUAN MANUEL ROJAS RIPARI; CYNTHIA A. URSINO; REBOREDA, JUAN CARLOS; DE MÁRSICO, MARÍA CECILIA

Nueva Jersey

Congreso; 51th Animal Behavior Society Conference; 2014

Animal Behavoir Society

Title Evidence of innate vocal mimicry of host young by the brood-parasitic screaming cowbird Authors JM Rojas Ripari , C Ursino, JC Reboreda, MC De Mársico Institution Departamento de Ecología Genética y Evolución ? IEGEBA (CONICET), FCEN, Universidad de Buenos Aires Abstract Body Young of obligate avian brood parasites, in order to obtain adequate levels of parental care, must tune their begging into the host?s existing parent-offspring communication system. The host-specialist screaming cowbird (Molothrus rufoaxillaris) possesses begging calls that resemble those of its primary host, the baywing (Agelaioides badius). We studied whether such vocal resemblance develops innately in screaming cowbird chicks. We used a discriminant function analysis (DFA) to examine differences in begging call structure among baywing chicks and screaming cowbird chicks that were either reared by baywings or experimentally cross-fostered as eggs to a non-host species (Mimus saturninus). DFA distinguished among these three groups of chicks with 73, 91 and 83% accuracy, respectively, based on max and min frequency, bandwidth and call duration Also, we tested the function of parasite?s begging calls using a playback experiment at baywing nests. Hosts responded similarly to broadcasts of begging calls of conspecifics and those of screaming cowbirds reared by baywings or M. saturninus. Our results strongly suggest a genetic basis for host-specific vocal mimicry in screaming cowbirds.