Least Bell's Vireo (Vireo bellii pusillus) and Arizona Bell's Vireo (Vireo bell arizonae), restriction site-associated DNA sequencing data (ddRADseq) throughout California, Arizona, Nevada, and Utah, USA (2020-2021).
These data were used examine gene flow and genetic diversity in the endangered Least Bell's Vireo, a migratory songbird dependent upon riparian habitat for breeding, and in its sister subspecies, the Arizona Bell's Vireo.