Call Learning in the Carduelinae: Ethological and Systematic Considerations

Abstract

Call Learning in the Carduelinae: Ethological and systematic considerations. Syst. Zool. 28:270–283.—Experiments and field observations document vocal imitation in six cardueline species representing four genera. Flight call learning was found in all birds studied; learning of many other call types was observed in two genera. Additional evidence extends call learning to other carduelines bringing to eight the total number of genera in which call learning has been observed. Call learning is perhaps characteristic of subfamily Carduelinae, and the taxonomist should consider the possibility that learning may affect the patterns of all adult cardueline vocalizations. The taxonomic value of cardueline calls in particular and passerine calls in general is re-examined in light of this extensive call learning. It is suggested that the ontogenetic, learned modification in call pattern can be eliminated from the taxonomic analysis, and that calls may then be taxonomically valuable behavioral characters. The problem of homologizing behavior is discussed, with criteria for homology applied to two call types, both associated with call learning. Cardueline flight calls are autapoinorphic characters useful as species specific characters, while social/alarm calls are synapomorphic at the subfamilial level and can be used as taxonomic characters at the family level.