Author ORCID Identifier

http://orcid.org/0000-0001-9314-6700

Document Type

Article

Publication Date

1-2014

Publication Title

Auk

Volume

131

Issue

1

First Page

41

Keywords

Acoustic variation, geographic variation, House Wren, latitudinal variation, morphological divergence, song divergence, species limits, Troglodytes, vocalization

Last Page

54

Abstract

Phenotypic traits are important for assessing differences between populations, especially in groups with poorly resolved taxonomy. One such group, the House Wren complex, presents extensive taxonomic controversy and is thought to comprise many independent evolutionary units. Although the songs and morphological features of House Wrens (Troglodytes aedon) show extensive variation, differences between populations have not been quantified. We assessed variation in acoustic and morphometric traits within this complex and compared patterns of variation with currently recognized subspecies boundaries. First, we compared songs and morphology among eight recognized subspecies (T. a. aedon, T. a. parkmanii, T. a. cahooni, T. a. brunneicollis, T. a. nitidus, T. a. musculus, T. a. beani, and T. a. rufescens), controlling for significant effects of latitude. Second, we used variation in male song, a trait with an important role in mate choice and male–male competition, to assess divergence among subspecies. We compared variation among subspecies to variation across seven currently recognized Troglodytes species (T. hiemalis, T. pacificus, T. tanneri, T. sissonii, T. cobbi, T. rufociliatus, and T. ochraceus). Our results, based on broad sampling of songs (n¼786) and morphological traits (n ¼ 401) from 609 locations throughout the Americas, show that most of the subspecies examined diverge in song, morphology, or both. In addition, the acoustic differences between subspecies are similar to, and in some instances greater than, the divergence between pairs of currently recognized species. Our results suggest that at least four allopatric subspecies—T. a. nitidus, T. a. musculus, T. a. beani, and T. a. rufescens—are likely different species, and we identify many other vocally and morphologically differentiated subspecies that may, upon further detailed genetic analysis, result in new species.

DOI

10.1642/AUK-13-161.1

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