One of our most recent #BeakoftheWeek‘s, the great curassow, is the focus of todays blog.
Curassows belong to the family Cracidae alongside the guans and chachalacas, and are the largest members of this group. The cracids are important seed dispersers in the Neotropical forests where the family is found. The great curassow is the largest cracid and can reach lengths of up to one metre from beak to tail. The male is a very striking bird with predominantly black plumage, a curly crest of feathers on his head, white under-tail coverts and a bright yellow knob (or cere) on his bill. The females exist in three colour morphs; a reddy-brown morph with barred tail, a dark morph and a barred morph. All lack the yellow cere of the male.
The great curassow is predominantly a frugivore, and perhaps unsurprising due to it’s large size, feeds mainly on fruits that have dropped to the forest floor, such as these guavas. Less frequently, it feeds in low branches and shrubs on attached fruits. It has also been reported to occasionally eat invertebrates and even small vertebrates (e.g amphibians) which are gleaned from the surface of leaves and amongst the leaf litter. It forages for food alone, in pairs or in small groups outside the breeding season, but can form large aggregations when trees such as figs are in fruit.
The calls of these birds vary from a low-pitched, deep, booming note to high-pitched peeping notes that are given in alarm. When escaping danger, the great curassow is more likely to run across the forest floor than it is to fly.
A monogamous pair bond is considered the norm in great curassows. Both members of the pair contribute to building the nest, which is placed 4-9 metres off the ground and is a platform made from sticks lined with leaves. The female lays 2 white eggs which take around a month to hatch. The chicks are buff coloured with black and chestnut markings and are precocial, being mobile soon after hatching. The female may carry chicks away from danger in their first few days of life. Great curassows are long-lived and one female in captivity was recorded to live to 24 years of age.
These birds have a wide but fragmented distribution and are found in the dense lowland forests of Southern Mexico, Central America down to Western Colombia and Ecuador. The great curassows’ population has been suspected to have declined rapidly over the past 30 years and was estimated at between 10,000-60,000 individuals in 2009. This species is particularly sensitive to hunting and habitat disturbance from the logging industry and settlement progression, and with population declines predicted to continue, it is listed by the IUCN as vulnerable.
A number of conservation schemes are currently in place with more being planned to reverse the population decline of the great curassow. You can find out more about them on BirdLife International’s website.
Atkinson, Jon, C. Rodríguez-Flores, C. Soberanes-González, and M.C. Arizmendi. 2012. Great Curassow (Crax rubra), Neotropical Birds Online (T. S. Schulenberg, Editor). Ithaca: Cornell Lab of Ornithology; retrieved from Neotropical Birds Online: http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=81671
BirdLife International 2012. Crax rubra. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 28 May 2015
BirdLife International (2015) Species factsheet: Crax rubra. Downloaded from http://www.birdlife.org on 27/05/2015
del Hoyo, J. & Kirwan, G.M. (2013). Great Curassow (Crax rubra). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2013). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/53311 on 27 May 2015).
The great curassow (Crax rubra) by Instituto Nacional de Biodiversidad Costa Rica (INBio) is licensed under CC BY-NC-SA 3.0