[vc_row][vc_column][vc_column_text]

Ornate Tree Lizard (Urosaurus ornatus)

[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column][/vc_row][vc_row][vc_column width=”1/2″][vc_single_image image=”1279″ img_size=”large” alignment=”center” style=”vc_box_rounded”][vc_column_text]Ornate Tree Lizard, Northern Jaguar Reserve, Sonora, MX. Photo by Jim Rorabaugh[/vc_column_text][/vc_column][vc_column width=”1/2″][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”1805″ img_size=”medium” alignment=”center” onclick=”img_link_large”][vc_column_text]Adult female Ornate Tree Lizard. Photo by Cecil Schwalbe[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”1806″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Dorsal scalation of Ornate Tree Lizard. Photo by Jim Rorabaugh[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][/vc_row_inner][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”1808″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Adult male Ornate Tree Lizard, Rancho Los Fresnos, Sonora, MX. Photo by Jim Rorabaugh[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”1807″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Ornate Tree Lizard with bifurcated tail, Glendale, AZ. Photo by Jim Rorabaugh[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][/vc_row_inner][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”1810″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Territorial battle between male Ornate Tree Lizards, Gendale, AZ. Photo by Jim Rorabaugh[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”1809″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Mating Ornate Tree Lizards, Marijilda Cyn, Pinaleno Mtns. Photo by Jim Rorabaugh[/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row][vc_column width=”1/6″][/vc_column][vc_column width=”2/3″][vc_column_text]

Description

The Ornate Tree Lizard (Urosaurus ornatus) is one of the most widespread, common, and familiar lizards in the 100-Mile Circle. It is also one of the most well-studied reptiles in our area. This is a relatively slender, small (< 62 mm SVL, although most adults are < 56 mm SVL) species. The original (not regrown) tail is less than twice the SVL. An anterior gular fold is evident, but only on the sides of the neck. It has mostly granular dorsal scales, but two adjacent rows of enlarged paravertebral scales on each side of the mid-dorsal line are separated by irregular rows of smaller scales in the mid-dorsal region. Scales atop the head are enlarged, as well. The frontal scale is divided. There are 10-11 femoral pores on each thigh.

The dorsum is gray, brown, or tan with varying numbers and intensity of dark blotches and crossbars; blue areas cover almost the entire abdominal surface in the adult male, but are faint or absent in the female. In young males the blue abdominal patches are paired, but in adults they are fused. The blue abdominal coloration may extend onto the sides or the dorsum, most commonly in populations south of Arizona. The throat, which can be extended as a behavioral display (see image gallery), is blue, blue-green, yellow or orange, sometimes with combinations of those colors in the male. The color is fixed in adults, but can change in juvenile males. The female venter is mostly whitish with sparse dark or colored pigmentation, and the throat patch is white, pale yellow or yellow-green. Throat color intensifies in gravid females.

Males have enlarged post-anal scales and in at least some populations, are on average of greater SVL (Tinkle and Dunham 1983) or have proportionally longer tails (Zucker 1987) than the females. Hatchlings are similar to adult females in color and patterning but are 22-27 mm SVL (Parker 1973, Alva 2014). Crother (2012) recognized six subspecies of Urosaurus ornatus. Schott’s Tree Lizard (U. o. schottii) occurs in our area; however, Haenel (2007) found substantial divisions within this subspecies and unique haplotypes in each population examined, suggesting additional, currently unrecognized taxonomic complexity.

In the 100-Mile Circle, the Ornate Tree Lizard is most likely to be confused with the Long-tailed Brush Lizard. However, that species has 5-7 longitudinal rows of enlarged, keeled scales on the middle of the dorsum and the original (not regrown) tail is 1.8-2.4 times SVL. The Ornate Tree Lizard is also widespread in our area, whereas the Long-tailed Brush Lizard is found from the Avra Valley west, and in southern and western Maricopa and western Pinal counties. Where the two Urosaurus occur in close proximity, Ornate Tree Lizards usually occupy the limbs and larger branches of large trees, whereas the Long-tailed Brush Lizard is more likely to be found in canopies of small trees or in shrubs (Vitt et al. 1981).

In the 100-Mile Circle, the Ornate Tree Lizard occurs in Sonoran and Chihuahuan desertscrub, semi-desert grassland, Plains grassland, inland chaparral, oak woodland, and pine-oak woodland. Its distribution may extend upslope into mixed conifer forest. In the Sonoran desert it is most abundant in the Arizona upland subdivision, but can be found along streams, rivers, and washes in the Colorado River subdivision as well. The species is usually absent from creosote flats devoid of rocks. It does well in urban, rural, and agricultural areas wherever there are trees, buildings, or other structure it can use for climbing. Its documented elevational range in the Circle is from about 320 m on the Gila River to 2285 m in the Pinaleño Mountains. This species is likely ubiquitous throughout the 100-Mile Circle except for the highest elevations and rockless creosote flats.

Ornate Tree Lizards occur from extreme southwestern Wyoming south through Utah and western Colorado to the lower Colorado River on the west, eastward to the eastern edge of the Edwards Plateau of Texas, and south through Arizona, New Mexico, Sonora, portions of Chihuahua and Coahuila, and southward to central Sinaloa. It also occurs on several islands in the Gulf of California, and has been introduced to the urban areas of El Centro and San Bernardino in southern California.

This species can be found in and about rocks, or in trees. In the Sonoran Desert this is primarily an arboreal species on flats and bajadas, but is found in rocks in mountain ranges. In New Mexico it is mostly saxicolous (Degenhardt et al. 1996). At the Rincon Unit of Saguaro National Park, Ornate Tree Lizards consistently inhabited the largest and most complex trees along washes, which were usually mesquite > 30 cm in circumference (Russell 1985), although they were also found on dead, standing saguaros in that area (M’Closky et al. 1987b).   At the confluence of the Salt and Verde rivers, Ornate Tree Lizards were most common on the trunks and large limbs of mesquite where canopies were overlapping, mean trunk diameter was 0.67 m, and mean tree height was 8.78 m (Vitt et al. 1981). In urban areas, Ornate Tree Lizards are common on block walls, buildings, wood piles, and a variety of large native and non-native trees. The Ornate Tree Lizard was found to be the most-urban adapted native lizard in the Tucson area (Germaine and Wakeling 2001).  It is also the most common native lizard in urbanized Phoenix (Ackley et al. 2015).

In central and northern Arizona, morphology of the Ornate Tree Lizard varied with habitat type. A cliff population was characterized by a flat, wide body and head, and relatively short limb segments. In boulder areas, the lizards exhibited long toes on the hind limbs, short proximal limb segments, and long tails. Tree populations had slender bodies, long tails, and long proximal limb segments (Herrel et al. 2001). The authors contend that these morphological attributes are adaptations to the varying environmental conditions. In the Chiricahua Mountains, Smith (1996) found that Ornate Tree Lizards were heavier and with greater mean SVL in woodlands than in adjacent rocky slopes. Feldman et al. (2011) found genetic distinction between rocky habitat and tree-dwelling Ornate Tree Lizards.

The species can be abundant, often in riparian areas (Gates 1963, Zucker 1987). In a cottonwood, willow, sycamore, and other riparian tree woodland on Sycamore Creek near Sunflower, unmanipulated lizard densities varied from 79.8-190 lizards per ha over a seven year period (Tinkle and Dunham 1983). Smith (1981) estimated a density of 143/ha in pine-oak woodland in the Chiricahua Mountains. Szabo (2014) reported densities of 20-150/ha at six sites in the Chiricahua Mountains. However, the highest density recorded was in rocky habitat in Hidalgo County, New Mexico: 721/ha (Dunham 1982). Densities are highest when recent precipitation has been above normal. Populations decline in drought years (Martin 1977, Dunham 1981, Ballinger 1984, Rosen and Lowe 1996), and in times of low food abundance (Ballinger 1977).

This is a diurnal species, although some feeding may occur after sunset (Asplund 1964). Ornate Tree Lizards tend to bask in the morning and then shuttle between shade and sun to maintain a fairly constant body temperature. They enter crevices in trees or hide under bark to avoid extremes in temperature (Vitt et al. 1981). In the Indo Mountains of Texas, body temperatures ranged from 24.0-40.2⁰ C with a mean of 33.6⁰ (Szabo 2014). At the confluence of the Salt and Verde rivers, body temperatures ranged from 34.5-39.9⁰ C (Vitt et al. 1981).

Unlike the closely related Long-tailed Brush Lizard, which maintains a state of deep hibernation in winter, the Ornate Tree Lizard can be observed active through the winter months on warm days, at least at lower elevation sites (Payne and Gatten 1988). In Maricopa County, Gates (1963) found Ornate Tree Lizards active from February into November. At Sycamore Creek near Sunflower, lizards became active in late February and early March, and most ended their activity period in mid-October. Only a few were seen in November (Tinkle and Dunham 1983). Winter aggregations of this lizard have been noted in rock crevices in Texas (Worthington and Sabath 1966) and under large granite slabs in the Sunflower area (Tinkle and Dunham 1983). Vitt (1974) and Vitt et al. (1981) also noted winter aggregations in central Arizona. Estivation may occur in very hot and dry periods (Haase 2009).

The Ornate Tree Lizard is a relatively short-lived, early-maturing, and multiple egg clutch species (Tinkle and Dunham 1983). Very few individuals live to an age of three or more years (Degenhardt et al. 1996). Aspects of reproduction vary across the species’ extensive range (Dunham 1982, Goldberg 2013). However, lizards reach sexual maturity before they are one year of age, males produce sperm in spring and summer, and eggs are laid from about June into September. At South Mountain, males and females were sexually mature at about 45 mm SVL (Parker 1973). Minimum size at maturity on Sycamore Creek near Sunflower was 45 mm SVL (female) and 43 mm SVL (male). However, in Sonora, males and females matured at 42 mm SVL (Goldberg 2013). Minimum size at maturity in New Mexico was reportedly 39 mm SVL (Martin 1977, Ballinger 1977) and 41 mm SVL in Texas (Dunham 1981).

Males and females may be reproductively active from March through early September, but the precise timing varies with geography (Fitch 1970, Goldberg 2013). At Sycamore Creek, females were reproductive from late May to late August (Tinkle and Dunham 1983). At South Mountain, females were gravid from late March through August, and males had enlarged testes from March through July (Parker 1973). In Sonora, males produced sperm from May into August, and females were found with enlarged follicles or oviductal eggs during June through August (Goldberg 2013). In central Arizona, female ovulation continued into September (Van Loben Sels and Vitt 1984).

Clutches of 2-16 have been reported, and 1-6 clutches are produced per year (Parker 1973, Haase 2009). Clutch size in Sonora was 6-13 (mean=8.6), but no evidence of multiple clutches was found (Goldberg 2013). At South Mountain, clutch size was 2-7 (mean=4.8) and at Aravaipa clutch size was 5-9 with a mean of 6.9 (Parker 1973). At Sycamore Creek, clutch size was correlated with SVL, and larger clutches were produced early (May and June) versus later in the season (July and August, Tinkle and Dunham 1983). Also at that site, females produced a maximum of three clutches per year. Haenel (2011) found larger clutch sizes in Ornate Tree Lizards inhabiting trees versus those living among rocks.

This is a behaviorally complex species, with interesting morphological and ecological correlates. Males are quite territorial, at least during the breeding season; females are less so (Milstead 1970, Deslippe et al. 1990). Home ranges are relatively small, and lizards do not or only rarely move across areas of poor habitat (Zucker 1989, Russell 1985). At Big Bend, both males and females remained territorial after the breeding season (Dunham 1980). Males perched higher than females in trees during the breeding season in New Mexico (Zucker 1986). In populations where it varies, the throat color of male Ornate Tree Lizards is indicative of behavior and dominance. Blue or blue-green throated males, as well as males with bi-colored throats, are aggressive and defend territories, whereas yellow-throated males are less aggressive and defend smaller territories, and orange-throated males are usually nomadic, but will defend territories when resources are abundant (Thompson and Moore 1991, Moore and Moore 1991, Knapp et al. 2003). As well, males with larger abdominal blue patches have a greater bite force, and may fare better in aggressive encounters (Meyers et al. 2006). Blue-throated males in southeastern Arizona grasslands had longer heads than other morphs (Lattanzio 2014). Dominant males may be darker in dorsal coloration (Carpenter and Grubits 1960, Zucker 1987). Females, however, are attracted by a suite of factors, not just throat color, including body mass and head size as well as body and tail coloration (Smith and Zucker 1997, Hamilton and Sullivan 2005).

In burned grassland areas of southeastern Arizona, dominant morphs and those lizards with divergent (non-average) morphologies exhibited enhanced survival. In the burned sites, there were fewer trees and thus more restricted habitat, resulting in increased spatial overlap and more-intense social interactions among male lizards (Lattanzio 2014).

The diet of Urosaurus ornatus consists of a variety of arthropods, such as ants, beetles, true bugs, beetle larvae, and other small arthropods, including scorpions (Asplund 1964, Vitt et al. 1981, Haase 2009). At the confluence of the Salt and Verde rivers, the Ornate Tree Lizard foraged primarily on tree trunks and large limbs. The percentage of animal prey by volume was 35.94 in the form of terrestrial/arboreal species, 23.75 outer canopy species, and 13.82 mixed outer canopy and tree trunk species. Ants made up 29.3% of the diet by volume. Prey items that were most available were taken in the greatest quantities (Vitt et al. 1981).

At Agua Caliente Wash near Tucson, diet (by frequency) varied seasonally (Asplund 1964). Ants were important during all seasons, but in winter and spring Homopterans (mostly leafhoppers) predominated, followed by ants and Hemiptera (true bugs). Hemiptera was commonly consumed in May. At the beginning of the summer rains, winged ants and termites were the most common dietary items, followed by Coleoptera (beetles). Later in the summer, ants followed by beetles predominated. In autumn, ants were supplemented by termites and Homoptera (mostly leafhoppers). Asplund observed feeding both on the ground and in trees. Ornate Tree Lizards are sit and wait predators, perching on tree trunks and limbs, or rocks, until prey comes within range.

In southeastern Arizona grasslands, Lattanzio (2014) found complex relationships among throat color (dominance), diet, and level of disturbance (fire). Dominant blue males were found to be dietary specialists, feeding often on predatory arthropods. Orange-throated males were dietary generalists and opportunistic, and yellow-throated males were plastic, in that their diet did not track prey availability. In burned grasslands sites, predatory arthropod diversity is less than in unburned sites. There are also fewer trees in burned sites, which are favored habitat for Ornate Tree Lizards. Morphs with greater dietary plasticity or that are opportunistic have an advantage, at least from a dietary perspective, despite the fact that they are less behaviorally dominant (Lattanzio 2014). Because the Ornate Tree Lizard favors trees, it has probably benefited from recent deterioration of southwestern grasslands, and associated invasion of trees and shrubs into those vegetation communities.

This lizard is likely preyed upon by a variety of snakes, other lizards, birds, and mammals. At Sycamore Creek near Sunflower, the Sonoran Whipsnake (Coluber bilineatus) was considered a likely important predator of the Ornate Tree Lizard and was observed stalking and attacking them (Tinkle and Dunham 1983). The Canyon Lizard (Sceloporus merriami) and the Ornate Tree Lizard are competitors in Texas (Dunham 1980), and competition between the Striped Plateau Lizard (Sceloporus virgatus) and the Ornate Tree Lizard was documented in the Chiricahua Mountains (Smith 1981).  Goldberg et al. (1993) investigated parasitic helminths in Ornate Tree Lizards. Szabo (2014) found Ornate Tree Lizards to be parasitized by chiggers and malaria (Plasmodium sp.) in the Chiricahua Mountains.

The Ornate Tree Lizard is listed as a species of least concern on the 2015 IUCN Red List. With a valid Arizona hunting license, 20 can be collected per day or possessed, alive or dead. There is no reason to believe the Ornate Tree Lizard is declining, and it is one of very few native reptiles or amphibians that thrives in heavily developed areas.

Suggested Reading:

Ackley, J.W., J. Wu, M.J. Angilletta Jr., S.W. Myint, and B. Sullivan. 2015. Rich lizards: How affluence and land cover influence the diversity and abundance of desert reptiles in an urban landscape. Biological Conservation 182:87-92.

Alva, J.S. 2014. Thermal ecology of Urosaurus ornatus (Ornate Tree Lizard) in the northern Chihuahuan Desert on Indo Mountains Research Station, Texas. Thesis. University of Texas at El Paso.

Asplund, K.K. 1964. Seasonal variation in the diet of Urosaurus ornatus in a riparian community. Herpetologica 20:91-94.

Asplund, K.K., and C.H. Lowe. 1964. Reproductive cycles of the Iguanid lizards Urosaurus ornatus and Uta stansburiana in southeastern Arizona. Journal of Morphology 115:27-33.

Ballinger, R.E. 1977. Reproductive strategies: food availability as a source of proximal variation in a lizard. Ecology 58: 628-635.

Ballinger, R.E. 1984. Survivorship of the lizard, Urosaurus ornatus linearis, in New Mexico. Journal of Herpetology 18(4):480-481.

Brennan, T.C., and A.T. Holycross. 2006. Amphibians and Reptiles in Arizona. Arizona Game and Fish Department, Phoenix, AZ.

Carpenter, C.C., and G. Grubits. 1960. Dominance shifts in the tree lizard (Urosaurus ornatus-Iguanidae). The Southwestern Naturalist 5:123-128.

Crother, B.I. 2012. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding, seventh edition. Society for the Study of Amphibians and Reptiles, Herpetological Circular (39):1-92.

Congdon, J.D., L.J. Vitt, R.C. Van Loben Sels, and R.D. Ohmart. 1982. The ecological significance of water flux rates in arboreal desert lizards of the genus Urosaurus. Physiological Zoology 55: 317-322.

Cooper Jr., W.E. 2005. Duration of movement as a lizard foraging movement variable. Herpetologica 61 (4): 363-372.

Degenhardt, W.G., C.W. Painter, and A.H. Price. 1996. Amphibians and Reptiles of New Mexico. University of New Mexico Press, Albuquerque.

Deslippe, R.J., S.P. Dajezak, and C.P. Szpak. 1990. Female tree lizards: oviposition and activity patterns during the breeding season. Copeia 1990:877-880.

Dunham, A.E. 1980. An experimental study of interspecific competition between the iguanid lizards Sceloporus merriami and Urosaurus ornatus. Ecological Monographs 50:304-330.

Dunham, A.E. 1981. Populations in a fluctuating environment: the comparative population ecology of the iguanid lizards Sceloporus merriami and Urosaurus ornatus. Miscellaneous Publications Museum of Zoology, University of Michigan (158):1-62.

Dunham, A.E. 1982. Demographic and life history variation among populations of the iguanid lizard Urosaurus ornatus: implications for the study of life history phenomenon in lizards. Herpetologica 38(1):208-221.

Feldman, C.R.; O. Flores-Villela, and T.J. Papenfuss. 2011. Phylogeny, biogeography, and display evolution in the tree and brush lizard genus Urosaurus (Squamata: Phrynosomatidae). Molecular Phylogenetics and Evolution 61 (3):714-725.

Fitch, H. S. 1970. Reproductive cycles in lizards and snakes. Univ. Kans. Mus. Nat. Hist. Misc. Publ. 52:1-247.

Gates, G.O. 1963. Ecology of the iguanid lizard Urosaurus ornatus in Arizona. Dissertation, University of Arizona.

Germaine, S.S., and B.F. Wakeling. 2001. Lizard species distributions and habitat occupation along an urban gradient in Tucson, Arizona, USA. Biological Conservation 97:229-237.

Goldberg, S.R. 2013. Reproduction in the Ornate Tree Lizard (Urosaurus ornatus), from Sonora, Mexico. Sonoran Herpetologist 26(3):47-51.

Goldberg, S.R., C.R. Bursey, and N. Zucker. 1993. Gastrointestinal helminths of the Tree Lizard, Urosaurus ornatus (Phrynosomatidae). J. Helminthol. Soc. Wash. 60(1):118-121.

Haase, R. 2009. Ornate Tree Lizard: Urosaurus ornatus (Baird and Girard 1852). Pp 290-293 in L.C. Jones and R.E. Lovich (editors), Lizards of the American Southwest: A Photographic Field Guide. Rio Nuevo Publishers, Tucson, Arizona.

Haenel, G.J. 2009. Isolation and characterization of microsatellite markers in tree lizards (Urosaurus ornatus). Molecular Ecology Resources 9:597–599.

Haenel, G.J. 1997. Mitochondrial DNA variation in populations of the tree lizard, Urosaurus ornatus. Copeia 1997 (1):174-178.

Haenel, G.J. 2007. Phylogeography of the tree lizard, Urosaurus ornatus: responses of populations to past climate change. Molecular Ecology 16:4321–4334.

Haenel, G.J. 2011. Effects of habitat on clutch size of ornate tree lizards, Urosaurus ornatus. Western North American Naturalist 71:247-256.

Hamilton, P.S., and B.K. Sullivan. 2005. Female mate attraction in ornate tree lizards, Urosaurus ornatus: a multivariate analysis. Animal Behaviour 69:219-224.

Herrel, A., J.J. Meyers, and B. Van Hooydonck. 2001. Correlations between habitat use and body shape in a phrynosomatid lizard (Urosaurus ornatus): a population-level analysis. Biological Journal of the Linnean Society 74(3):305-314.

Knapp, R., D.K. Hews, C.W. Thompson, L.E. Ray, and M.C. Moore. 2003. Environmental and endocrine correlates of tactic switching by nonterritorial male tree lizards (Urosaurus ornatus). Hormones and Behavior 43(1):83–92.

Lattanzio, M.S. 2014. Ecological and phenotypic divergence among Ornate Tree Lizard (Urosaurus ornatus) color morphs in response to environmental variation. Dissertation. College of Arts and Sciences of Ohio University.

Lowe Jr., C.H., and V.J. Vance. 1955. Acclimation of the critical thermal maximum of the reptile Urosaurus ornatus. Science 122: 73-74.

Martin, R.F. 1977. Variation in reproductive productivity of range margin tree lizards. Copeia 1977:83-92.

M’Closkey, R.T., K.A. Baia, and R.W. Russell. 1987a. Defense of mates: a territory departure rule for male tree lizards following sex-ratio manipulation. Oecologia 73:28-31.

M’Closkey, R.T., K.A. Baia, and R.W. Russell. 1987b. Tree Lizard (Urosaurus ornatus) territories: experimental perturbation of the sex ratio. Ecology 68:2059–2062.

Meyers, J.J., D.J. Irschick, B. Vanhooydonck, and A. Herrel. 2006. Divergent roles for multiple sexual signals in a polygynous lizard. Functional Ecology 20:709–716.

Milstead, W.W. 1970. Late summer behavior of the lizards Sceloporus merriami and Urosaurus ornatus in the field. Herpetologica 26:341-357.

Moore, C.W., and M.C. Moore. 1991. Throat colour reliably signals status in male tree lizards, Urosaurus ornatus. Animal Behavior 42(5):745-753.

Parker, W.S. 1973. Natural history notes on the iguanid lizard Urosaurus ornatus. Journal of Herpetology 7(1): 21-26.

Payne, J.C., and R.E. Gatten. 1988. Thermal acclimation of activity metabolism in desert lizards (Urosaurus graciosus and U. ornatus). Journal of Thermal Biology 13(1):37-42.

Robson, M.A., and D.B. Miles. 2000. Locomotor performance and dominance in male Tree Lizards, Urosaurus ornatus. Functional Ecology 14:338–344.

Rosen, P.C., and C.H. Lowe. 1996. Ecology of the amphibians and reptiles at Organ Pipe Cactus National Monument, Arizona. USDI, National Biological Service, Cooperative Park Studies Unit, University of Arizona and the National Park Service, Organ Pipe Cactus National Monument. Technical Report No. 53.

Russell, R.W. 1985. Demography and habitat utilization of Urosaurus ornatus (Sauria: Iguanidae) in southeastern Arizona. Thesis and dissertation. University of Windsor. Paper 1625.

Smith, D.C. 1981. Competitive interactions of the striped plateau lizard (Sceloporus virgatus) and the tree lizard (Urosaurus ornatus). Ecology 62:679-687.

Smith, G.R. 1996. Habitat use and its effect on body size distribution in a population of the tree lizard, Urosaurus ornatus. Journal of Herpetology 30(4):528-530.

Smith, G.R., and R.E. Ballinger. 1994. Thermal ecology of Sceloporus virgatus from southeastern Arizona, with comparison to Urosaurus ornatus. Journal of Herpetology 28:65-69.

Smith, G.R., and R.E. Ballinger. 1995. Temperature relationships of the Tree Lizard, Urosaurus ornatus, from desert and low-elevation montane populations in the Southwestern USA. Journal of Herpetology. 29:126-129.

Smith, G.R., and R.E. Ballinger. 1995. Female reproduction in Urosaurus ornatus from the Chiricahua Mountains of southeastern Arizona. Herpetological Natural History 3 (2):183-186.

Smith, J.M., and N. Zucker. 1997. Do female Tree Lizards, Urosaurus ornatus, exhibit mate choice? Journal of Herpetology 31(2):179-186.

Szabo, A. 2014. Factors influencing parasite load in male ornate tree lizards (Urosaurus ornatus): throat colour, population density, and habitat type. Thesis. Department of Earth Sciences University of Ottawa.

Thompson, C.W., and M.C. Moore 1991. Throat colour reliably signals status in male tree lizards, Urosaurus ornatus. Animal Behavior 42:745-753.

Tinkle, D.W., and A.E. Dunham. 1983. Demography of the Tree Lizard, Urosaurus ornatus, in central Arizona. Copeia 1983(3):585-598.

Van Loben Sels, R.C., and L.J. Vitt. 1984. Desert lizard reproduction: seasonal and annual variation in Urosaurus ornatus. Canadian Journal of Zoology 62(9):1779-1787.

Vitt, L.J. 1974. Winter aggregations, size classes and relative tail breaks in the tree lizard, Urosaurus ornatus (Sauria: Iguanidae). Herpetologica 30:182-183.

Vitt L.J., R.C. Van Loben Sels, and R.D. Ohmart. 1981. Ecological relationships among arboreal desert lizards. Ecology 62:398-410.

Worthington, R.D., and M.D. Sabath. 1966. Winter aggregations of the lizard Urosaurus ornatus ornatus (Baird and Girard) in Texas. Herpetologica 22(2):94-94.

Zucker, N. 1986. Perch height preferences of male and female tree lizards, Urosaurus ornatus, a matter of food competition or social role? Journal of Herpetology 20:547-553.

Zucker, N. 1987. Behavior and movement patterns of the Tree Lizard Urosaurus ornatus (Sauria: Iguanidae) in semi-natural enclosures. The Southwestern Naturalist. 32:321-333.

Zucker, N. 1989. Dorsal darkening and territoriality in a wild population of the Tree Lizard, Urosaurus ornatus. Journal of Herpetology. 23:389-398.

Author:  Jim Rorabaugh

For information on this species, please see the following volume and pages in the Sonoran Herpetologist: 2013 Sep:49-51.

[/vc_column_text][/vc_column][vc_column width=”1/6″][/vc_column][/vc_row][vc_row][vc_column][gap size=”30px” id=”” class=”” style=””][/vc_column][/vc_row]