Nape of South American (the three leftmost specimens) and Central American (the two other specimens) representatives of the Aramides cajaneus species complex. Note the much stronger color in the latter.

 
 
  Part of: Marcondes RS, Silveira LF (2015) A taxonomic review of Aramides cajaneus (Aves, Gruiformes, Rallidae) with notes on morphological variation in other species of the genus. ZooKeys 500: 111-140. https://doi.org/10.3897/zookeys.500.7685