Thanks to Larry for posting the Yellow-rumped Warbler impending split information. I knew of the rumblings of a split, but wasn't familiar with two of the proposed four species.
In the article referred to in Larry's post, these two are discussed briefly and it is noted that they are allopatric. That means they are isolated, separate populations. I followed up on this to learn where they occur. I found:
"blackfronted warbler"). D. c. nigrifrons - breeds Chihuahua and Durango mountains in western Mexico. ...
Goldman's Warbler, of Guatemala, resembles Audubon's but has a white lower border to the yellow throat and otherwise darker plumage;
Thus, these two species (assuming the split becomes "official") will not be additions to the ABA list--unless Blackfronted strays up into the US Southwest--, but will be added to the North America list. (Alas, not my personal list...yet.)