Bats
The California Myotis ranges throughout western North America, from southern Alaska south into Guatemala, and is one of the most abundant bats in desert scrub habitats. It also can be found in oak and ponderosa pine woodlands. Throughout its range, it roosts beneath loose bark and in crevices of old dead and dying trees. It also forms small maternity colonies in cliffs, buildings, and bridges.
Like many species, California Myotis switch roosts on a regular basis, sometimes within a few feet, sometimes up to a mile apart. Roost-switching may aid the bats in finding ideal roost temperatures and avoiding predators and parasites. In most cases, roosts are located near feeding areas.
These bats are among North America’s smallest, enabling them to feed on especially tiny insect prey. It was not until miniature radio transmitters could be outfitted to weigh less than half a gram that these bats could be tracked and their roosts identified.