Much headway has been made on information about the natural history of Eared Quetzal since it was considered an extremely rare and elusive resident of the high mountain forests. However, many details of its systematics and life history remain unclear or unknown. In particular, its relationship with other trogons outside the monophyletic quetzal group is disputed, with contradicting arguments being published. Its diet is very poorly described, while details of its foraging behavior are still lacking beyond its general preference for 'sally-stalling'. Virtually nothing is known about its territoriality except that most people agree that individuals occupy large ranges, without information of territory density, size, or the behavior exhibited to defend it. No information was found on extra-pair paternities, and the early stages of courtship remain unknown, excepting the frequent uttering of the bird’s song. The structure or purpose of intraspecific flocking outside the breeding season is completely undescribed, as are the quetzal’s relationship with predators. Also the finer details of the bird’s phenology are incomplete, while the age at first breeding, the life span, survivorship, diseases, parasites, and causes of mortality for this species are unknown.