Cracidae

(vertebrate zoology) A family of New World tropical upland game birds in the order Galliformes; includes the chachalacas, guans, and curassows.

(Cracidae)

Class: Aves

Order: Galliformes

Suborder: Craci

Family: Cracidae

Thumbnail description
A group of Neotropical gamebirds, long-tailed and medium to large in size

Size
16.5–36.2 in (42–92 cm); 0.8–9.5 lb (385–4,300 g)

Number of genera, species
11 genera; 50 species

Habitat
Predominately tropical forest and woodland

Conservation status
Critically Endangered: 3 species; Endangered: 4 species; Vulnerable: 7 species; Near Threatened: 8 species; Extinct in the Wild: 1 species

Distribution
South Texas to central Argentina

Evolution and systematics

Cracids are a primitive, ancestral family of gamebirds (Galliformes), probably originating in Central America and southern North America. The earliest known cracid is recognized by a fossil approximately 50 million years old, found in Wyoming. This primitive bird appeared to be primarily arboreal, living at a time when most of North America was tropical. Younger fossils (around 30 million years old) similar to chachalacas have been found in nearby South Dakota. Recent fragments (approximately 20,000 years old) of more contemporary cracid fossils (e.g., Crax, Penelope) have been found within their existing range. The cracids are most closely related to the moundbuilders (Megapodiidae).

In Peter's checklist, the cracids form a family with 8 genera and 44 species. In other, more recent classifications, the family has 11 genera and 50 species. The chachalacas (Ortalis), with 12 species, are the smallest members of the family, and characterized by more drab coloration, lack of sexual dimorphism, and the ability to occupy a variety of habitats including secondary growth. The medium-sized guans are represented by six genera: true guans (Penelope) with 15 species, piping guans (Pipile) and sickle-winged guans (Chamaepetes) with four and two species, respectively, and three monotypic genera: the wattled guan (Aburria aburri), the highland guan (Penelopina nigra), and the horned guans (Oreophasis derbianus). Coloring in guans ranges from drab to dramatic, and sexual dimorphism is present in only a few species. Curassows are the largest cracids, represented by four genera: the monotypic nocturnal curassow (Nothocrax urumutum), the razor-billed curassows (Mitu) with four species, helmeted curassows (Pauxi) with two species, and the true curassows (Crax) with seven species.

Physical characteristics

The Cracidae range in size from scarcely as large as a black grouse (Lyrurus tetrix) to almost turkey-sized. They replace the pheasants of Asia in tropical America and are in some respects also reminiscent of the American turkeys. Spanish-speaking Latin Americans therefore call them pavos or pavones (turkeys), or faisanes (pheasants). Their length is 16.5–36.2 in (42–92 cm), and weight is 0.8–9.5 lb (385–4,300 g). These birds are slim, long-legged, and have short, rounded wings and a fairly long tail. The beak is strong but fairly short and lightly curved, often with a conspicuous cere at the base. The feet are like those of the moundbuilders and, in contrast to the Phasianidae, they have long, well-developed hind toes on the tarsus at the same level as the other toes ("pigeon-footed"). Cracids have a long caecum; in many species the trachea is prolonged. The plumage is mainly a shiny black or olive-brown to reddish brown, often with white marks, which form a crest on the head of some species. The feathers lack an aftershaft. The great curassow's head generally has an erectile crest of stiff, forward-curled feathers. In many curassow species the males have a fleshy knob or hump on the root of the beak, or bare, brightly colored areas of skin on the head. The cere of the beak is often colorful.

Distribution

Cracids are restricted to the New World, distributed from south Texas through most of tropical South America as far as central Argentina. Perhaps one of the most puzzling and intriguing patterns of cracid distribution is that some of the highland species show a strongly disjunct (separate) distribution, while many of the lowland forms are strongly parapatric (their distributions adjoin each other rather than overlap). Riverine barriers may be a cause of the strong parapatric distribution of many lowland forms; other more disjunct species may have displayed more continuous distributions historically.

The countries harboring the highest diversity of cracids are Colombia and Brazil, with 24 and 22 species, respectively. In contrast, the United States harbors only a single species: the plain chachalaca (Ortalis vetula).

About 13 of the cracids are regionally restricted (six restricted to Brazil, three to Colombia, two to Mexico, and one each to Peru and Trinidad). The species with the widest distributions are perhaps the rusty-margined guan (Penelope superciliaris), which ranges through most of eastern tropical South America, and Spix's guan (Penelope jacquacu), which ranges through most of the western Amazon Basin. In contrast, the most range-restricted species is perhaps the Alagoas curassow (Mitu mitu) which is likely extinct in the wild and occurs only in captivity.

Habitat

The large members of the family are birds of dense tropical forest country. Some live in areas with a long dry season where the trees periodically shed their leaves, or in the "fringing forests" that extend along waterways in otherwise treeless country. Most guans are dependent upon primary forest, but a few Penelope species are able to tolerate secondary habitat. Curassows are almost invariably dependent upon tropical forest. The smaller chachalacas avoid the interior of dense forests and are at home in light secondary growth, such as secondary growth forest on formerly cultivated land. Chachalacas may live on plantations or near houses as long as there are trees and shrubs nearby and they are not disturbed. Most species inhabit warmer lowlands, though some occur in cooler mountain forests up to altitudes exceeding 9,800 ft (3,000 m).

All cracids are adapted to tree life. They walk about lightly and skillfully on thin branches in the tops of trees. Before crossing a woodland clearing, they jump and fly from branch to branch until they have reached the top of the highest tree at the edge of the clearing. From there they launch themselves into the air and as soon as they have gained enough speed in their fall, they spread their wings and glide downwards, often over distances far greater than 330 ft (100 m). Only when this glide will not enable them to reach their goal do they beat their wings to gain height. However, occasionally even heavy species like the great curassow undertake more distant aerial journeys. Cracids roost in trees overnight.

Behavior

Since the Cracidae are so shy and generally avoid humans, little is known about their social life. There are indications that at least some species live in polygamy; male yellow-knobbed curassows (Crax daubentoni), for example, may be found in the breeding season with three, four, or occasionally more hens. Guans are found at all seasons more or less socially in flocks, and their nests sometimes stand together in groups.

The vocalizations of the Cracidae are loud and rarely pleasant to the human ear. In a number of species, the vocal power of the cocks, and sometimes of the hen as well, is increased by a prolonged trachea. It runs far back between skin and breast muscles, and then turns and runs forward to the point of entry into the chest cavity.

Apart from vocal utterances, several species of this family also produce drumming or clattering sounds with the wings during special display flights. The drumming sound of the black guan sounds "sharper" than the crested guan's wing drumming, because in the latter the ends of the two outermost primaries have almost no vanes, but only bare shafts.

Altitudinal migration apparently occurs in some of the montane species.

Feeding ecology and diet

Cracids are mainly plant eaters, but eat insects and other small animals to a lesser extent. They feed mainly on fruit and seeds that ripen during the course of the year in the tropical forests. They swallow berries and other small fruits whole, however, they will bite into larger fruit like mangoes and guavas. They also bite off soft leaves and opening buds. Insects, snails, and other small animals form only very small parts of the menu. Now and then the birds come down from the trees to eat. When feeding on the ground, cracids, in contrast to many other Galliformes, do not appear to scratch the ground.

The general trend in diet appears to be more leaves and flowers and less fruit in smaller species (chachalacas), to more fruit and fewer leaves in larger species (curassows). The large curassows gather large numbers of fallen fruit on the forest floor. Similarly, animal matter seems to be more prevalent in the diets of smaller species (e.g., insects in the diet of chachalacas, snails in the diet of piping guans) than in curassows.

A crop is present as a dilatation of the gullet in curassows and in the horned guan. Other members of the family, which lack a crop, have a distensible gullet, so that food can be stored in it before digestion begins. The stomach is emptied first, and then food enters it from the crop or the gullet. Smaller seeds are passed through, whereas larger seeds are regurgitated on the spot. As the birds disperse the seeds of their preferred food plants throughout the forest in this way, they help regenerate the tropical forests in which they live.

Reproductive biology

The Cracidae build their nests in trees or in bushes in the forest or in thickets. The nest is a rough, disorderly structure shaped like a flat dish or a platform with a depression, which is often longer than it is wide. It is built from twigs, climbing plant stems, leaves, grass, palm frond pieces, and similar items. Larger species may use branches of 0.8–1.2 in (2–3 cm) in diameter for the nest base. Often they pluck leaf-bearing twigs or grasses that they bring to the nest while still fresh and green.

Hens appear to lay only two eggs in curassows, often three in chachalacas, and three or four eggs in guans. A clutch of nine plain chachalaca eggs found by R. J. Fleetwood was evidently derived from three hens. As far as is known, all Cracidae lay white eggs. The thick shell is usually rough and grainy or has markings that resemble pin pricks. Often the eggs are surprisingly large. During incubation, particularly in wet weather, the white eggs become stained by the leaves on which they lie.

For most species it appears that only hens incubate the eggs. A female chachalaca observed by Skutch interrupted her incubation twice a day, once in the early morning, and again late in the afternoon, staying off the eggs from 60 to 75 minutes each time. Incubation periods vary according to species. The eggs of chachalacas may hatch in 21–23 days, but incubation lasts 34–36 days in the horned guan.

Cracid chicks are well developed at hatching, and the young are very soon able to fly or at least to flutter over short distances. They leave the nest very soon after their down is dry, sometimes even before. Skutch observed a chachalaca feeding its chicks soon after hatching. After the last chick had become dry, it was another three hours before the mother got down to the ground from the nest, which was 5 ft (1.5 m) high. The young left the nest with her. Cracids can move at birth, and fly, hop, and walk along twigs at quite a respectable height when only a few days old.

Conservation status

Cracids are the most threatened family of birds in the Americas. Of the 50 species, about half are of conservation concern. This includes nine of the 14 species (64%) of the curassows, but only two of the 12 species (16%) of the chachalacas; the other threatened species are guans, of which approximately 50% are threatened. The main threats are a combination of overhunting and habitat destruction.

Young cracids do not reproduce until they are two years old, and they breed only once a year with each hen rearing few young. Compared to other gallinaceous birds, cracids thus have a very low rate of reproduction. Only when humans appear on the scene and pursue them with firearms does their low rate of reproduction become insufficient and consequently dangerous. Wherever these birds are not protected by sensible and strictly enforced laws, they are in danger of extermination. Only the small chachalacas, which can adapt to the plants of cultivated country and are less desirable as food for humans, seem able to flourish in more densely settled and cultivated areas.

Significance to humans

Indigenous tribes may use tail or wing feathers in their ornamentation. Additionally, cracids constitute an important protein source in the diets of hunters in Latin America and often represent a substantial portion of the prey base. Unfortunately, the life history of cracids will often not permit intensive hunting pressure due to their low reproductive rate, long generation time, dependence upon specific habitat, and poor dispersal qualities. Because cracids are so heavily affected by both hunting and habitat destruction, they can be used effectively as bioindicator species for managing parks and protected areas in the Neotropics. By monitoring the population status of cracids in a particular area, wildlife managers can determine whether or not the forest resources in a given region are being over-exploited.

Species accounts

Resources

Birdlife International. Threatened Birds of the World. Barcelona: Lynx Edicions, 2000.

Brooks, Daniel M., and Fernando Gonzalez-Garcia. Biology and Conservation of Cracids in the New Millenium. Houston: Miscellaneous Publications of the Houston Museum of Natural Science, Number 2, 2001.

Brooks, Daniel M., et al. Biology and Conservation of the Piping Guans (Pipile). Houston: Special Monograph Series of the Cracid Specialist Group, Number 1, 1999.

Brooks, Daniel M., and Stuart D. Strahl. Cracids: Status Survey and Conservation Action Plan. Switzerland: IUCN, 2000.

Delacour, Jean, and Dean Amadon. Curassows and Related Birds. New York: The American Museum of Natural History, 1973.

Strahl, Stuart D., et al. The Cracidae: Their Biology and Conservation. Washington: Hancock House Publications, 1997.

The Cracid Specialist Group. PO Box 132038, Houston, TX 77219-2038 USA. Phone: (713) 639-4776. E-mail: dbrooks @hmns.org Web site:

Neotropical Bird Club. c/o The Lodge, Sandy, Bedfordshire SG19 2DL United Kingdom. E-mail: secretary @neotropicalbirdclub.org

[Article by: Daniel M. Brooks, PhD]

The noun has one meaning:

Meaning #1: curassows; guans; chachalacas
  Synonym: family Cracidae

Chachalacas, Guans, Curassows
Spix's Guan, Penelope jacquacu
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Aves Order: Galliformes Family: Cracidae Vigors, 1825
Genera
Aburria Chamaepetes Crax Mitu Nothocrax Oreophasis Ortalis Pauxi Penelope Penelopina

The chachalacas, guans and curassows are birds in the family Cracidae.

These are species of tropical and subtropical Central and South America. One species, the Plain Chachalaca, just reaches southernmost Texas in the USA. Two species, the Trinidad Piping Guan and the Rufous-vented Chachalaca occur on the islands of Trinidad and Tobago respectively.

Contents 1 Biology 2 Systematics and evolution 2.1 Evolution 3 Footnotes 4 References 5 External links

Biology

Cracids are large birds, similar in general appearance to turkeys. The guans and curassows live in trees, but the smaller chachalacas are found in more open scrubby habitats. Many species are fairly long tailed, which may be an aide to navigating their largely arboreal existence. They are generally dull-plumaged, but the curassows and some guans have colourful facial ornaments. The birds are particular vocal, with the chachalacas taking their name from the sound of their call^[1]. Cracids range in size from the Little Chachalaca (Ortalis motmot), at as little as 38 cm (15 in) and 350 g (12.5 oz), to the Great Curassow (Crax rubra), at nearly 1 m (40 in) and 4.3 kg (9.5 lbs).

These species feed on fruit, insects and worms. They build nesta in trees, and lay two to three large white eggs, which only the female incubates alone. The young are precocial and are born with an instinct to immediately climb and seek refuge in the nesting tree. They are able to fly within days of birth^[1].

Systematics and evolution

The Cracidae are an ancient group related to the Australasian Mound-builders. They are sometimes united with these in a distinct order, "Craciformes", but this is not supported by more recent research which suggests that either is a well-marked, basal lineage of Galliformes.

Plain Chachalacas, Ortalis vetula

FAMILY: CRACIDAE

• Subfamily Penelopinae, Guans
  • Genus Penelopina
    • Highland Guan, Penelopina nigra
  • Genus Chamaepetes
    • Black Guan, Chamaepetes unicolor
    • Sickle-winged Guan, Chamaepetes goudotii
  • Genus Penelope (15 species)
  • Genus Aburria - piping-guans (5 species, includes Pipile)

Subfamily N.N.^[2]

• • Genus Ortalis - Chachalacas (12 species)
• Subfamily Oreophasinae
  • Genus Oreophasis, Horned Guan
• Subfamily Cracinae, Curassows
  • Genus Nothocrax
    • Nocturnal Curassow, Nothocrax urumutum
  • Genus Crax (7 species)
  • Genus Mitu
    • Crestless Curassow, Mitu tomentosa
    • Salvin's Curassow, Mitu salvini
    • Razor-billed Curassow, Mitu tuberosa
    • Alagoas Curassow, Mitu mitu (extinct in the wild)
  • Genus Pauxi, Helmeted curassows (2 species)

Alternatively, all subfamilies except the Penelopinae could be lumped into the Cracinae. As the initial radiation of cracids is not well resolved at present (see below), the system used here seems more appropriate. It is also quite probable that entirely extinct subfamilies exist as the fossil record is utterly incomplete.

Evolution

Female Bare-faced Curassow (Crax fasciolata)

Recent research has analyzed mt and nDNA sequences, morphological, and biogeographical data to study the phylogenetic relationships of cracid birds, namely the relationships among the genera (Pereira et al., 2002), the relationships between the species of curassows (Pereira & Baker, 2004) and between the piping- and Wattled Guans (Grau et al., 2005). The traditional groups - chachalacas, guans, and curassows - are verified as distinct clades, but the Horned Guan represents the sole survivor of a very distinct and ancient lineage.

In addition, the molecular data suggest that the Cracidae originated in the Late Cretaceous, but the authors caution that this cannot be more than a hypothesis at present: as the rate of molecular evolution is neither constant over time nor uniform between genera and even species, dating based on molecular information has a very low accuracy over such long timespans and needs to be corroborated by fossil evidence. The fossil record of cracids is limited to a single doubtfully distinct genus of chachalaca, Boreortalis (Hawthorn Early Miocene of Florida, USA; may actually be a junior synonym of Ortalis) and some species in the modern genus Ortalis, however. This does not provide any assistance in evaluating the hypothesis (Pereira et al., 2002) that the split between the 4 main lineages of our time occurred quite rapidly, approximately in the Oligocene or slightly earlier, somewhere between 40 and 20 mya.

The genera Procrax, Palaeonossax and Paleophasianus are often considered cracids, but this is not certain at all; they may belong to a related extinct lineage. It is unfortunate that of these too, few good fossils are known, as they date to about the time when the modern groups presumably diverged. Should they be cracids, they are not unlikely to represent either some of the last members of the family before guans, chachalacas, etc. evolved, or very early representatives of these lineages.

Thus, the assumption that the modern diversity started to evolve in the late Paleogene, continuing throughout the Miocene and onwards, must also be considered hypothetical given the lack of robust evidence. Still, the "molecular" scenario is entirely possible considering what is known about the evolution and radiation of the Galloanserae, and consistent with the paleogeography of the Americas. The ichnotaxon Tristraguloolithus cracioides is based on fossil eggshell fragments from the Late Cretaceous Oldman Formation of southern Alberta, Canada which are similar to chachalaca eggs (Zelenitsky et al., 1996), but in the absence of bone material their relationships cannot be determined except that they are apparently not from a dinosaur.

By comparison, speciation within curassows (Crax, Nothocrax, Pauxi and Mitu) and the piping/wattled guans is supported by better evidence. It was usually caused by changes in topography which divided populations (vicariant speciation), mainly due to the uplift of the Andes which led to the establishment of the modern river basins. The distribution of curassow and piping-guan species for the most part follows the layout of these river systems, and in the latter case, apparently many extinctions of populations in lowland areas (Grau et al., 2005). Another result was that the Wattled Guan belongs to the same genus as the piping-guans, which thus use the older name Aburria (Grau et al., 2005).

Footnotes

1. ^ ^{a b} Rands, Michael R.W. (1991). Forshaw, Joseph. ed. Encyclopaedia of Animals: Birds. London: Merehurst Press. pp. 89. ISBN 1-85391-186-0. 
2. ^ Though this group would also be classified at subfamily level, it has usually been lumped with the Penelopinae due to misinterpreted plesiomorphies (Pereira et al. 2002). In any case, the name Ortalinae is currently occupied.^{[verification needed]}

References

• Grau, Erwin T.; Pereira, Sérgio Luiz; Silveira, Luís Fábio; Höfling, Elizabeth & Wanjtal, Anita (2005): Molecular phylogenetics and biogeography of Neotropical piping guans (Aves: Galliformes): Pipile Bonaparte, 1856 is synonym of Aburria Reichenbach, 1853. Molecular Phylogenetics and Evolution 35: 637-645. doi:doi:10.1016/j.ympev.2004.12.004 PDF fulltext

• del Hoyo, J. (1994). Family Cracidae (Chachalacas, Guans and Curassows). Pp.310–363 in; del Hoyo, J., Elliott, A. & Sargatal, J. eds. 'Handbook of the Birds of the World, Vol. 2. New World Vultures to Guineafowl. Lynx Edicions, Barcelona. ISBN 8487334156

• Pereira, Sérgio Luiz & Baker, Allan J. (2004): Vicariant speciation of curassows (Aves, Cracidae): a hypothesis based on mitochondrial DNA phylogeny. Auk 121(3): 682-694. [English with Spanish abstract] DOI:10.1642/0004-8038(2004)121[0682:VSOCAC]2.0.CO;2 HTML abstract HTML fulltext without images

• Pereira, Sérgio Luiz; Baker, Allan J.& Wajntal, Anita (2002): Combined nuclear and mitochondrial DNA sequences resolve generic relationships within the Cracidae (Galliformes, Aves). Systematic Biology 51(6): 946-958. doi:10.1080/10635150290102519 PDF fulltext

• Zelenitsky, Darla K.; Hills, L. V. & Currie, Philip J. (1996): Parataxonomic classification of ornithoid eggshell fragments from the Oldman Formation (Judith River Group; Upper Cretaceous), Southern Alberta. Canadian Journal of Earth Sciences 33(12): 1655-1667.

External links

• Cracidae videos on the Internet Bird Collection
• Cracid sounds on xeno-canto.org

Wikimedia Commons has media related to: Cracidae

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