IOC: Pacific-slope Flycatcher Empidonax difficilis and Cordilleran Flycatcher E. occidentalis (including hellmayri) are re-lumped, restoring the original name Western Flycatcher Empidonax difficilis to the recombined species. The two forms demonstrate extensive hybridization in a broad contact zone in w Canada and the northern western USA and lack consistent vocal, genomic and morphological differences (Rush et al. 2009; lack et al. 2019; Hopping 2022; Chesser et al. 2023).