Although the Guianan Cock-of-the-rock is a large, stocky bird, they fly agilely through the forest (Snow 1982). Forage for fruit with sallies (Snow 1982).
Regurgitates large seeds; consequently, quantities of seeds often accumulate on the ground below and near the nest.
Males defend individual display courts on the lek.
Mating system and sex ratios
Guianan Cock-of-the-rock is polygynous, with a single male breeding with multiple females.
The Guianan Cock-of-the-rock maintains no long term pair bonds. The female lays the eggs and rears the young with no assistance from the male.
The Guianan Cock-of-the-rock males display at a lek (communal display area). At the lek, each male maintains a separate "court", cleared of vegetation, on the forest floor. Males spend much of their time, however, perched above the court, generally at about 1.5 to 2 m above the court (Trail 1987). When a female visits the lek, males descend to their courts, ruffle their plumage, and crouch motionless. (Gilliard 1962, Sick 1984.) The small curled filament tips of the secondaries on the wings are moved up into a fan like shape when faced against a small breeze (Gilliard 1962, Sick 1984.)
If a female descends to a male's courts, she then may tap him on the back or shoulder. This is followed by copulation. A female may return later to copulate again, either with the same male or with another (Trail 1989). About two-thirds (67%) of the males at one lek failed to reproduce, while the most successful male performed an average of 30% of the total number of annual matings (Trail 1969).
Social and interspecific behavior
The Guianan Cock-of-the-rock is a solitary, other than at the lek.
At one site in Suriname, the primary predators of Guianan Cock-of-the-rock at the lek were Ornate Hawk-Eagle (Spizaetus ornatus) and Collared Forest-Falcon (Micrastur semitorquatus), based on the number of raptor attacks (Trail 1987). Additional species that also staged attacks on cock-of-the-rock were Bicolored Hawk (Accipiter bicolor), White Hawk (Pseudastur albicollis), Great Black Hawk (Buteogallus urubitinga), and Crested Eagle (Morphnus guianensis). Harpy Eagle (Harpia harpyja), Black-and-white Hawk-Eagle (Spizaetus melanoleucus), Black Hawk-Eagle (Spizaetus tyrannus), and Slaty-backed Forest-Falcon (Micrastur mirandollei) were present in the same forest, but were not observed to attack cock-of-the rock. (Trail 1987). Felids such as ocelot (Leopardus pardalis) are potential predators, and cock-of-the-rock fly to the canopy and give alarm calls in the presence of cats; but mammal predation on cock-of-the-rock has not been documented (Trail 1987). Several species of bird-eating snakes potentially are predadors of cock-of-the-rock, and predation is documented for boa constrictor (Boa constrictor). At one site, three males were killed within the same lek by the same boa in the course of a year (Trail 1987).
Response to predation
The Guianan Cock-of-the-rock has been shown to have less predation in larger lek groups due to the alertness of having several individuals on the lookout for predators. Within a large group, more spooks (“false” alarm) are likely to happen due to the amount of birds looking for predators and alarming the large lek group (Trail 1987). In the lek, the response to predators is the vocalization projected at the stimulus (Trail 1987). Usually after such a call, the majority of the birds at the lek retreat ca 20-30 m up into trees. Predation by snakes, however, did not seem to cause an alarm call or a spook. Most of the time when a snake was passing through the lek, none of the birds took notice; the birds did not even give an alarm call when a male was attacked on his court by a boa (Trail 1987).