Although the Greater Roadrunner occurs throughout Texas, is well known, is the topic of much folklore, and is a very popular cartoon character, the only field research studies that have been conducted are in desert scrub or brush-grassland habitats in South Texas. As a popular multicultural iconic bird, from prehistory to modern time, it is surprising that it was one of the last bird species to be given state protection because of the mistaken belief that roadrunners were a threat to declining quail populations.
DISTRIBUTION: The Greater Roadrunner is a resident of Texas, recorded in all counties(Maxon 2005), but is most common in the Chihuahuan Desert of West Texas and the South Texas brushlands (Sauer et al. 2005). However, the author sighted many roadrunners from August 16-18, 1999, in Cottle, Foard, King, and Knox counties in the northwest Rolling Plains ecoregion. They are locally uncommon to common in all other areas except the forested eastern and northeastern sectors where they are rare to locally uncommon (Lockwood and Freeman 2004).
Density data are available for the South Texas brush-grasslands (Roth 1971) — one singing male/8 ha (20 acresto 1/40 ha (98 acres) Density data are also available for the Coastal Bend region of South Texas — 1 breeding pair/65-81 ha (160-200 acres; Folse 1974), 1.5 individuals/100 ha (247 acres; Emlen 1972) and 2.5-3.1 individuals/100 ha (247 acres; Folse and Arnold 1978). Greater Roadrunners have linear territories; those measured by Folse and Arnold (1978) were (0.3-1.0 km (0.2-0.6 mi) in length with a mean of 0.6 km (0.4 mi); territories in Trans-Pecos (Hughes 1996) averaged 0.8 kn (0.5 mi).
SEASONAL OCCURRENCE. Greater Roadrunners are year-round residents in Texas. They breed from early March to late-October; based on egg dates from. March 5-October 10 (Oberholser 1974) and may nest as many as 3 times during a favorable breeding season (Maxon 2005). Greater Roadrunners occur alone from late fall through winter and in pairs or family groups during the breeding season (Maxon 2005).
BREEDING HABITAT: Major habitat types used by Greater Roadrunner include desert scrub, chaparral, savannah, open brushlands, open woodlands, and wooded stream corridors including myriad plant communities within each habitat type; and, in urban and suburban areas such as yards, parks, agricultural lands, school grounds, cemeteries, and vacant lots. Roadrunners are, rare in dense unvegetated urban areas, dense brushlands, and woodlands with thick undergrowth (Maxon 2005).
All habitat types are similar in general vegetation structure — a mix of open area with sturdy vegetation. Ground cover may range from bare ground to sparse, short bunchgrass or short lawn grass, and the tall vegetation may be cacti, small bushes, or trees. The open areas are essential for feeding. Tall vegetation or artificial structures provide nesting and roosting sites (Maxon 2005). In general, Greater Roadrunners nest in thorny shrubs, low trees, thickets, and clumps of cacti. Specific nest distribution and nest site parameters were analyzed in South Texas by Folse and Arnold (1978) and Trans-Pecos (Hughes 1996).
STATUS: Between 1830-1900, the Greater Roadrunner extended its range in Texas to include the southeast, southwest, central, and Panhandle areas; and, between 1900-1940, its range extended into East Texas. This expansion coincided with conversion of grasslands to farms and ranches. Woody plant invasion of these modified areas was facilitated as a result of the end of American Bison (Bos bison) grazing, fire suppression, overgrazing by cattle, tree planting for windbreaks, over-farming, and farm abandonment. Thus, most of Texas provided ideal habitat — mixes of open land with shrubs or trees (Maxon 2005).
Historically, this is an unusually fast expansion for a ground-dwelling species whose individuals move only a few miles during their lifetimes. Therefore, further explanation is necessary to understand this range expansion. Three factors are involved (Maxon 2005). First, the prehistoric habitat of the Greater Roadrunner (33,500 years ago) was cool, open woodlands, rather than that of present-day desert scrub which is commonly thought of as its primary habitat. Thus, adaptation to a drying desert scrub-grassland environment required thousands of years; but it remains a woodland species more common near wooded areas than in the midst of low desert scrub. Second, extreme adaptability and flexibility involving simple habitat requirements (open areas in which to feed and tall vegetation nearby in which to roost and nest); omnivorous opportunistic diet; nest site flexibility (almost any sturdy vegetation or artificial structure); large clutch size (usually 3-6, wwith a mean of 4 but occasionally from 2-12), and asymmetric hatching offset predation, especially of snakes (the major predators); long breeding season with up to 3 nesting attempts/season during favorable years; and, longevity (at least 7-9 years). Third, human changes in the landscape that enhanced habitats (clearing of plains and prairies, elimination of bison and fire suppression, both of which allowed trees and shrubs to invade grasslands, planting trees in former grasslands around homes and fencerows, clearing openings in closed-canopy woodlands and forests, and draining wetlands for farming,. and human tolerance of suburban areas that still retain natural habitat features.
In the Coastal Bend region of South Texas, local populations fluctuated considerably depending upon the relative success of the previous breeding season (Folse and Arnold 1978). North American Breeding Bird Survey data for Texas (Sauer et al. 2005) give annual trends of 6.4% (1966-1979), 3.2% (1980-2005), and 2.1% (1966-2005); thus, showing a slight overall decreasing trend. Six regions show both increasing and decreasing trends with general stability: Upper Coastal Plain (1.8% 1966-1979, -6.5% 1980-2005, -5.2% 1966-2005), South Texas Brushlands (4.6% 1966-1979, 7.1% 1980-2005, 2.1% 1966-2005), Osage Plains/Cross Timbers (-6.3% 1966-1979, 1.4% 1980-2005, 0.1% 1966-2005), Edwards Plateau (1.7% 1966-1979, 2.4% 1980-2005, 2.5% 1966-2005), Rolling Red Plains (-22.5% 1966-1979, 14.5% 1980-2005, 10.9% 1966-2005) and Chihuahuan Desert (13.8% 1966-1979, 1.3% 1980-2005, 3.3% 1966-2005). However, in the East Texas Prairies, there has been a significant decline (18.5% from 1966-1979, -18.5% from 1980-2005, and -0.6% from 1966-2005) where there has been significant vast urban-suburban development, planting of nonnative monoculture pasture grasses, overgrazing, cleanly farmed croplands, surface mining, and transportation corridors (Gunter and Oelschlaeger 1997, Telfair 1999).
Text by Raymond C. Telfair II (2007)
Emlen, J. T. 1972. Size and structure of a wintering avian community in southern Texas. Ecology 53: 317-329.
Folse, L. J., Jr. 1974. Population ecology of Roadrunners (Geococcyx californianus) in south Texas. MS thesis, Texas A&M University, College Station.
Folse, L. J., Jr. and K. A. Arnold. 1978. Population ecology of Roadrunners (Geococcyx californianus) in South Texas. Southwest. Nat. 23: 1-28.
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Hughes, J. M. 1996. Greater Roadrunner (Geococcyx californianus). In The Birds of North America, No. 244 (A. Poole and F. Gill, eds.) The Birds of North America, Inc., Philadelphia, PA.
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Telfair, R. C. II, ed.. 1999. Texas wildlife resources and land uses. University of Texas Press, Austin.