Eye colour is geographically variable in Lesser Roadrunner Geococcyx velox (Wagner, 1836)

All modern avian world taxonomies currently treat Lesser Roadrunner Geococcyx velox as monotypic. Since its description in 1836, however, five subspecies have been described based on tail pattern and underparts colour. These features were later found to be subject to individual and seasonal variation, and in the late 1990s the species was reclassified as monotypic. Here we present a previously overlooked diagnosable character that separates three geographic populations. We evaluated 1,400 photos archived in Macaulay Library and found consistent differences in iris colour, and no evidence of clinal connectivity, suggestive of divergence. We describe sectoral heterochromia for populations of Lesser Roadrunner in Yucatán and Honduras east to Nicaragua, a potential adaptation to foraging in tropical open habitats.