The American Ornithologists’ Union published the 51st supplement to its check-list of North American Birds in July of 2010. Here is a brief summary of the changes of interest to ABA birders. The updated AOU checklist, now with 2070 species, can be found at www.aou.org/checklist/north. The following splits affected ABA area birds: Black Scoter (Melanitta nigra) was split into American and Eurasian Species. The American species retains the common name Black Scoter (M. americana) and the Eurasian Scoter becomes Common Scoter (M. nigra). The Eurasian species has not yet been reported in the ABA Area.
Whip-poor-will (Caprimulgus vociferus) was split into two species: Eastern Whip-poor-will (C. vociferus) and Mexican Whip-poor-will (C. arizonae). Winter Wren (Troglodytes troglodytes) was split into three species: Eurasian Wren (T. tryglodytes), Winter Wren (T. hiemalis), and Pacific Wren (T. pacificus).
Pictures and texts comparing all of these splits can be found in Sibley’s Guide to Birds and the National Geographic Field Guide to North America. Songs can be found in the Stokes’ Field Guide to Bird Songs as well as on www.xeno-canto.org. Draft range maps for all species may be seen at www.sibleyguides.com.