http://blog.aba.org/2014/07/2014-aou-check-list-supplement-is-out.html
No significant N. America wood-warbler taxonomic changes have occurred except for the Arctic Warbler. (Read the link for more information.)
To me, the most interesting development was a restructuring of the King and Clapper Rail complex.
To wit, on the West Coast where I live the Clapper Rail is now Ridgway's Clapper Rail.
It contains three subspecies: the California (obsoletus), Yuma (yumanensis) and Light-footed (levipes).
Per the above link, the name "Clapper Rail" remains the same for the East Coast version of this bird, but its scientific name changed (to Rallus crepitans).