In another Arizona study, nest trees ranged from d.b.h. Most nests are placed in the upper third of the tree crown. Nests are placed from 16 to 90 feet (4.9–27) above the ground, usually on a large limb against the bole, or in the forks of smaller branches. Nests were most often built on the southern to southeastern side of the tree. Patton reports that nest trees in Arizona had crowns that were 35% to 55% of the total tree height, and most often were d.b.h.. Nests are built in trees occurring as part of a grouping of trees with interlocking crowns. Dwarf mistletoe ("Arceuthobium vaginatum") infestations that cause the formation of "witches brooms" are often incorporated into or support Abert's squirrel nests.