Tree lizards ( Urosaurus ornatus ) are among the most common lizards in the southwestern United States. You can often find them warming themselves in a sunny spot on a tree, fence, or wall, waiting for an insect snack to come crawling or flying by. Males have bright blue bellies and colored dewlaps. Females have orange dewlaps, but no blue belly patches. Look on your backyard fence for tree lizards in the summer.