About Ortalis columbiana Hellmayr, 1906
The Colombian chachalaca (Ortalis columbiana Hellmayr, 1906) is a typical large, plump Ortalis species, a forest bird with a long slender neck, small head, long robust tarsi (legs), and a long tail. Adult individuals measure 50–60 cm in total length. Average measurements differ between sexes: average wing length is 22.5 cm for males and 19.6 cm for females; average tail length is 25 cm for males and 24 cm for females; average tarsi length is 6 cm for males and 5.8 cm for females; typical adult mass is 600 g for males and 500 g for females. The appearance of males and females is similar or identical. The bird's upperparts are mostly brown, fading to greyish-brown on the primaries and secondaries. The outer tail feathers are rufous-brown. Its head and neck are grey, with a red dewlap on the neck. Its breast feathers are grey with prominent white scalloping, which is a distinguishing feature that separates it from the similar-looking speckled chachalaca. The belly is buffy, with rufous shading on the thighs and flanks, and rufous undertail coverts. Legs and feet are pinkish. The bill is dark grey at the base, shading to white at the tip. The iris is dark brown, and a patch of bare grey skin surrounds the eye. This species is endemic to the Cauca and Magdalena valleys of Colombia. It was once fairly widespread, but many years of hunting pressure and habitat loss have extirpated it from large portions of its former range. Its current distribution is highly fragmented, with only small, localized populations remaining in the upper river valleys: along the Magdalena from Huila Department to Santander, and along the Cauca valley from Cauca Department to Antioquia. The Colombian chachalaca inhabits the upper tropical zone, and is most commonly found on the edges of dry to humid forests and mature second growth. It can survive in degraded habitat such as scrub and thicket areas, and is relatively tolerant of human habitation in regions where it is not hunted or persecuted. Research indicates it is more likely to thrive in mature forests, where it can use fallen tree trunks for foraging, shelter, and nesting between tree roots. Colombian chachalacas are arboreal, spending most of their time in forests where they forage from the mid-level of the forest up to the canopy. They prefer trees with good food supplies, primarily Ficus or Cecropia species. They fly within and between trees, but do not usually make long flights. These birds are social, and groups of up to 20 individuals have been observed. They can be noisy, performing the chac-a-lac call choruses that give the species its common name. Little is known about the breeding habits of this species. Colombian chachalacas are presumed to be monogamous, and may hold territories during the breeding season. In the Magdalena valley, records of a female with a swollen brood patch, a male with extended testes, and a half-grown young bird were all collected in February, indicating this is the start of the breeding season in that area. Like other cracids, Colombian chachalacas are highly frugivorous. Large frugivores play a key role in maintaining tropical forest diversity: when they defecate indigestible large seeds, they help disperse the parent plant species. If large frugivores are removed from an area, it will become dominated by fast-growing species that produce smaller fruits and seeds. This species typically forages in pairs or small groups. In the Cauca valley, the species' diet was found to include 26 plant species, consisting of 77.2% fruits, 16.2% leaves, and 3.6% flowers. They also occasionally eat soil, dead leaves, and stones, which makes up 3% of their diet. Many seeds defecated by Colombian chachalacas have been shown to germinate at a higher rate than seeds extracted directly from fruit.
