P2.8 Thursday, Jan. 5 Variation in Flight Calls and Responsiveness among Individuals and Types in the Evening Grosbeak (Coccothraustes vespertinus) HAIMAN, Aaron/N.K.*; GENDI, Kirollos/M.; HAHN, Thomas/P.; Univ. of California, Davis; Univ. of California, Davis; Univ. of California, Davis email@example.com
The Evening Grosbeak (Coccothraustes vespertinus) is a nomadic species that ranges across North America. This species has been in decline in recent years, and the taxonomic status of its subspecies is uncertain. Five distinct variants, or types, in flight calls produced by individuals in different geographic areas have been observed. The specific acoustic variations that occur in the flight call, and the possibility that this species can use this vocalization to identify other members of the species to group or individual levels, has not been explored. Here we quantify variation in 240 flight calls of 24 individuals representing three western types (Type 1, Type 2, and Type 4). Our goal was to illustrate a possible mechanism by which individual and group membership could be determined using the acoustic parameters of the flight calls. Analyses of variation (ANOVA) and coefficients of variation (CV) show that the flight calls vary both between individuals of the same type and between types. Variation between types is more consistent across acoustic parameters than variation between individuals of the same type. To determine if these birds do discriminate between flight calls types, a playback experiment was conducted. Type 1 individuals were presented with recordings of their own flight call type and a foreign flight call type and levels of responsiveness were compared. Variation in vocalizations can allow identification at different group levels. The different activity rate of observed birds to recordings of different flight call types suggest that these birds can distinguish between flight calls types. These results could have significant influence on flock assemblage and mate selection, and so contribute to speciation in nomadic species.