of smaller size, around 6, predation was less likely to occur, due to an inverse relationship between the number and frequency of attacks and the size of leks. Thus, with a smaller frequency of attacks on the smaller group, the Guianan cock-of-the-rock males was less likely to flush or disperse completely as compared to a large group where a false alarm could trigger a complete flush 90% of the time. It was found that these birds have relatively ineffective methods of anti-predation and that social anti-predation and the infrequency of encounters with predators were keeping these lekking males alive. There is speculation that the simulation of male-male competition is important in lek formation and breeding. Impact of natural and sexual selection on trait development The colouration of the males allows them to visibly stand out from the brown forest floor. This bright colouration provides a sexual advantage for the adult males, increasing their likelihood of successfully mating. The result is rapid evolutionary selection within the species for brighter plumage and more conspicuous behaviour patterns in the males. The bright colouration also makes the males more susceptible to predation. Males are more expendable for this reason; only a small number of males are needed within any generation in order to perpetuate the species. While sexual selection leads to bright plumage, natural selection in turn favors defensive colouration in the birds. There is higher fitness in birds monitoring nests whose colouration acts as camouflage-protection from predation. Conservation Fairly common in its large range, and with its population stable, the Guianan cock-of-the-rock is considered by the International Union for Conservation of Nature to be a Least Concern on its red list of threatened species. The main predators of the Guianan cock-of-the-rock are harpy eagles, black-and-white hawk-eagles, black hawk-eagles and slaty-backed forest falcons. Felines such as the jaguar, mountain lion, and ocelot can also be predators, along with snakes such as the bird snake, tree boas, boa constrictor, tiger rat snake, and fer-de-lance. The species is rare in captivity, but breeding has been achieved at a small number of facilities. The world's first successful captive breeding was at Dallas World Aquarium (USA) in 2008. Predation response In larger lek groups there is less risk of predation. In a group there are more individuals to alert the group about an approaching predator. All the birds in the groups will be vigilant in looking for a