Cryptic speciation in the Warbling Vireo (Vireo gilvus)

Scott F. Lovell, M. Ross Lein & Sean M. Rogers
Eastern (Vireo gilvus gilvus) and western (V. g. swainsoni) forms of the Warbling Vireo have essentially allopatric breeding ranges across north-central North America, but come into contact in central Alberta, Canada. In 1986, Jon Barlow presented preliminary morphological and song evidence suggesting that the Warbling Vireo complex might comprise more than one valid species. However, to date Barlow’s suggestion is supported by only limited DNA evidence, demonstration of molt and migration differences between the taxa,...
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