Coloration, especially of the cheeks, throat and eye region, is very variable across the wide range, giving weight to the theory that these birds form a superspecies.

The related sooty-capped chlorospingus (C. pileatus) has a blacker head with a bold white supercilium rather than an eye spot.

[2] Its habitat – cloud forests with ample undergrowth and adjacent bushy clearings – is dominated by trees and shrubs from such families as Asteraceae, Clusiaceae, Cyatheaceae, Melastomataceae, Rubiaceae and Winteraceae, and epiphytes of the Araceae (e.g. Anthurium) and Orchidaceae.

[2] The common chlorospingus is usually encountered in small groups or as part of a mixed-species feeding flock,[3] and is rather sedentary.

[5] There is apparently no dedicated nesting season at least in the hottest parts of its range, but in general it seems that the common chlorospingus prefers to breed mainly between October and May.

[citation needed] The eggs are off-white and marked with larger puce and smaller maroon spots mainly on the blunt end.

More recent research suggests that they are actually aberrant brush finches[clarification needed] in the Passerellidae and particularly close to Arremonops.

The wide range and considerable morphological variation displayed by C. ophthalmicus has been a problem for ornithologists for many decades.

In addition, it would be interesting to determine whether there are geographical variations in the song that would further strengthen the case for species status of the taxa.

The morphological variation, though recognizable, is rather inconspicuous and probably more the consequence of genetic drift in freshly isolated subpopulations than a cause for their separation.

[8] Notably, the divergence between the northern clades seems to have occurred far too early for the Pleistocene ice ages to have played a major part.

Given its sedentary habits, the phylogeny seems to be a result of a combination of habitat expanding and constricting due to Pliocene climate changes and, less frequently, accidental dispersal (such as to the Sierra de los Tuxtlas and, earlier, to Mesoamerica in general).

[2] The flavopectus group contains larger birds which lack a pronounced brown tinge on the crown; many members have this area purely gray to blackish.

This group includes taxa such as C. o. flavopectus and C. o. nigriceps from central to southern Colombia, C. o. phaeocephalus from Ecuador, C. o. peruvianus from Peru, or C. o. cinereocephalus and C. o. hiaticolus.

They have a tendency to build their nests uncharacteristically high up in trees; for this reason, it is unknown whether one-egg clutches are as commonly seen in this population as they seem to occur in the flavopectus group.