It was long anticipated, and there goes a "species" from my (and many others') Life List. For me, the Cordilleran was akin to the old "Northwestern" Crow; not a 'real' species, so I will not miss having to listen to all those Blue & Rocky Mountain Empidonax birds and make a subjective 'guess' as to which species to put down on my eBird checklists.

In its 23rd supplement since publication of the 7th edition of the Check-list of North American Birds (AOU 1998) are summarized decisions made between 15 April 2022 and 25 April 2023 by the American Ornithological Society’s (formerly American Ornithologists’ Union) Committee on Classification and Nomenclature - North and Middle America.

The publication went online today, resulting in "... 1 species (Empidonax occidentalis) is lost by merger with a species already on the list"...