Individual differences in the vocalizations of the buff-throated woodcreeper (Xiphorhynchus guttatus), a suboscine bird of neotropical forests

Abstract

Unlike in temperate forests, bird communities in neo-tropical forests are largely composed of species of Tyranni, or suboscines, a suborder of passeriform birds that do not learn their songs. Thus, songs of suboscines are typically acoustically simple compared to the complex songs of Passeri, the oscine passeriforms. While a great deal is known about oscine song, few descriptions of the repertoires of tropical suboscines have been published, and relatively little is known about the use and function of song in suboscines. Additionally, whether suboscines can recognize individuals by voice alone has received little attention. One representative of these tropical suboscines is the buff-throated woodcreeper (Xiphorhynchus guttatus, Dendrocolaptinae), a bird commonly found in the forests of the tropical Americas. To investigate the possibility for individual variation in songs of this species, we recorded buff-throated woodcreepers at dawn and dusk in Amazonian Peru. From these recordings, we document two long-range song types, describe their acoustic parameters, and examine their occurrence at different times of day and across two seasons. Quantitative analysis of frequency, timing, and pattern of songs revealed that woodcreeper vocalizations varied significantly among individuals. A discriminant function analysis of song parameters successfully assigned a majority of songs to the correct individual. Despite their relatively simple structure, the vocalizations of buff-throated woodcreepers vary consistently among individuals but apparently not so distinctly as those of many oscines. Questions remain regarding whether the buffthroated woodcreeper can use these differences for individual recognition and how the two song types function in communication.