"The Riddle of digitallibrary.amnh.org/dspace/handle/2246/4831Oxyruncus&..., one of the legendary papers written by the dean of Neotropical ornithologists, Frank M. Chapman, documents a puzzle that is not yet solved and has becoming even more complicated! Here's the form from the Central Andes of Colombia.

https://colombia.inaturalist.org/observations/9426920
ebird.org/ebird/view/checklist/S28792678