Ortalis vetula
The members of the genus Ortalis, are arboreal residents of the New World tropics. They are in the same family as guans and curassows (Monroe and Sibley 1993, Am. Ornithol. Union 1998). All members of this family have traditionally been hunted for food by native peoples of the American tropics.
Plain Chachalacas eat a wide variety of plant material, including fruit, berries, buds, seeds, flowers and leaves, mostly obtained while climbing through shrubs and trees. In pursuit of a ripe fruit, a chachalaca may even hang upside down. These birds also consume insects and other invertebrates found during their arboreal travels. Chachalacas also adapt readily to bird feeding stations and may consume human crops as well (Peterson 2000).
The English name “chachalaca” is a transliteration of the “ear-splitting,” raucous calls of flocks, heard most frequently during morning hours of the long breeding season (Stiles and Skutch 1989, Howell and Webb 1995, Peterson 2000).
DISTRIBUTION. During the 1987-1992 field work seasons of the TBBA project, volunteers found 56 breeding sites for Plain Chachalacas in latilongs 26097 (11 confirmed, 18 probable and 1 possible), 26098 (4 confirmed, 14 probable and 5 possible) and 26099 (1 confirmed and 2 probable) in the South Texas Brush Country and Coastal Sand Plain regions (see the region map in Lockwood and Freeman [2004]). The only North American Breeding Bird Survey route reporting this species was Laguna Atascosa in Cameron County with an annual average of 3.4 individuals (Price et al. 1995).
South of Texas these chachalacas reside on the Gulf coastal plain of Mexico, on the Yucatan Peninsula and in Belize, Guatemala, Honduras and northern Nicaragua. The status of populations in Costa Rica remains to be decided (Stiles and Skutch 1989, Monroe and Sibley 1993, Howell and Webb 1995, Am. Ornithol. Union 1998, Peterson 2000).
SEASONAL OCCURRENCE. Plain Chachalacas are year-round resident in their range. They breed in Texas from early March to September, based on egg collection dates from March 21 to August 16 (Oberholser 1974, Lockwood and Freeman 2004).
BREEDING HABITAT. Plain Chachalacas breed in Texas from near sea level to about 90 m (300 ft) in thick woodlands of the lower Rio Grande valley (Oberholser 1974). Common nest trees include cedar elm, huisache, sugar hackberry, anaqua and Texas ebony with diameters ranging from 1.3-78.7 cm (0.5-31 in).Most trees are alive and draped with Spanish moss and vine tangles which help support and conceal nests. Most nests were in crotches or forks or on horizontal branches from 1.5-7 m (5-23 ft) above ground (Marion and Fleetwood 1978, Peterson 2000).
In Texas this chachalaca usually rejuvenates nests used previously or adapts nests of other birds such as Yellow-billed Cuckoo (Coccyzus americanus), Groove-billed Ani (Crotophaga sulcirostris) and Curve-billed Thrasher (Toxostoma curvirostre). The chachalaca nests (see picture opposite p. 147 in Harrison [1979]) appear flimsy. Eggs ,may also be laid on litter in tree crotches, in cavities or on bare horizontal branches. The mean maximun diameter of 42 oblong nests was 21,7 cm (8.7 in). The female generally lays 4 (range 2-4) roughly granular, buffy white eggs on alternate days and incubates them for 22-25 days. The young leave the nest immediately after their down dries and remain with their parents at least until October (Marion and Fleetwood 1978, Peterson 2000).
STATUS. Although the south Texas population of Plain Chachalacas was heavily impacted by market hunting in the late 1800s and early 1900s, classification as a game bird, introduction of hunting seasons and bag limits and urbanization of the lower Rio Grande valley have greatly reduced hunting pressure over the years (Peterson 2000).
Plain Chachalacas are now uncommon residents of the lower Rio Grande valley (Lockwood and Freeman 2004). The map in Oberholser (1974) shows a similar range to the TBBA map. Atlasers did not find evidence of breeding by chachalacas released just prior to the atlas field wonk in counties listed by Lockwood and Freeman (2004).
Text by Robert C. Tweit (2008)
Literature cited.
American Ornithologists’ Union. 1998. Checklist of North American birds, 7th ed. Am, Ornithol. Union, Washington, DC.
Harrison, H. H. 1979. A field guide to western birds’ nests. Houghton Mifflin, Boston, MA.
Howell, S. N. G. and S. Webb. 1995. A guide to the birds of Mexico and northern Central America. Oxford University Press, New York.
Lockwood, M. W. and B. Freeman. 2004. The TOS handbook of Texas birds. Texas A&M University Press, College Station.
Marion, W. R. and R. J. Fleetwood. 1978. Nesting ecology of the Plain Chachalaca in south Texas. Wilson Bull. 90: 386-395.
Monroe, B. L., Jr., and C. G. Sibley. 1993. A world checklist of birds. Yale University Press, New Haven, CT.
Oberholser, H. C. 1974. The bird life of Texas. University of Texas Press, Austin.
Peterson, M. J. 2000. Plain Chachalaca (Ortalis vetula). InThe birds of North America, No. 550 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
Price, J., S. Droege, and A. Price. 1995. The summer atlas of North American birds. Academic Press, New York.
Stiles, F. G. and A. F. Skutch. 1989. A guide to the birds of Costa Rica. Cornell University Press, Ithaca, NY.