Urosaurus ornatus

Habitat includes a wide range of situations from desert to the lower edge of the spruce-fir zone; usually this lizard perches on massive rocks or trees (mesquite, oak, pine, juniper, alder, cottonwood, tamarisk, rough-bark eucalyptus) (Hammerson 1999, Stebbins 2003), sometimes on fence posts or buildings. It is often associated with river courses. When inactive, it occurs in tree stumps, under bark, in rock crevices, in burrows, or similar protected sites. It lays eggs probably in soil/underground, or under rocks.

Population density estimated at about 40-83/ha in western Texas (Dunham 1980), up to about 190/ha in central Arizona (Tinkle and Dunham 1983). Annual adult survivorship often much less than 50% (see Ballinger 1984). Often aggregates during hibernation.

Tree lizards generally have relatively small home ranges. In western Colorado, home range size averages 154 sq m in males and 109 sq m in females (Christian and Waldschmidt 1984). In New Mexico, Zucker (1989) found that two-dimensional home range size is highly variable among different individuals and averages 70 sq m in males and 39 sq m in females (Zucker 1989). Some individuals may remain within areas just a few meters in diameter whereas others range over much larger areas (Zucker 1989). Mahrt (1998) reported that home range size is usually less than 50 sq m in southern New Mexico. Other studies have found large annual variations in home range size (see Zucker 1989).

Time of oviposition and clutch size (average varies from 3-11) vary greatly throughout range. Clutches/year: 1-2 in some areas, 3 or more elsewhere; yearlings may produce fewer clutches than do older ones. Mature in 1 year or less (Tinkle and Dunham 1983)