Birds showing notable sexual dimorphism ranging from South America to Central America

Crax are pheasant-like birds native to the tropical forests of Central and South America. These birds are known for their striking appearance, with species like the Great curassow (Crax rubra) being the most well-known due to its size and distinctive plumage.

Members of the Crax genus are characterized by their curly crests and crissum – the undertail coverts that are often brightly colored. Their plumage presents a dramatic dichotomy of white and reddish-brown, with males typically exhibiting more vibrant colors than females. This sexual dimorphism in plumage is not just for show; it plays a crucial role in courtship and mating behaviors.

The Great curassow, in particular, stands out as the largest and heaviest member of this genus. With a robust body and powerful legs, it is a majestic sight within the dense foliage of its habitat. These birds are most often encountered in small groups or pairs, foraging on the forest floor, where they feed on various food sources.

When it comes to nesting, Crax species generally build small, oval-shaped nests in trees, providing a safe haven above the forest floor where many predators roam. The exception within the genus is the Blue-billed curassow (Crax alberti), which constructs larger nests out of sticks and dead leaves. Females typically lay a clutch of two eggs, and with some species, both males and females participate in incubation and care for the young.

The diet of Crax birds is omnivorous, consisting of worms, seeds, fruits, small leaves, and insects. Their role as seed dispersers is critical to the health of their forest ecosystems. By consuming fruits and excreting the seeds elsewhere, they contribute to propagating many plant species within their habitat.

An intriguing aspect of the genus Crax is its ability to hybridize. Some species within the genus can interbreed and produce fertile offspring, which is relatively rare in the avian world. This hybridization can have implications for conservation, as it may affect the genetic diversity of populations.