The Ladder-backed Woodpecker (Picoides scalaris) is an uncommon resident of arid regions from California east to Texas and south to Nicaragua (Short 1971, AOU 1998). Although in Baja California the Ladder-backed Woodpecker occurs along the northwest coast at least as far as La Bufadora, 15–20 km southwest of Ensenada (Erickson and Howell 2001), its California distribution is transmontane (i.e., inland of the Transverse and Peninsular ranges), extending north to the desert slopes of the southern Sierra Nevada (Garrett and Dunn 1981). Cismontane (coastal slope) breeding has recently been documented in Miller Valley in southeastern San Diego County and from Damerson Valley of north-central San Diego County to Aguanga in adjacent Riverside County; these small valleys support many elements of desert biota (Unitt 2004). Occupied habitats in California typically include desert slopes vegetated with Joshua Tree (Yucca brevifolia) or Desert Agave (Agave deserti), desert washes and arroyos, riparian oases, and occasionally pinyon–juniper woodland. Ladder-backed Woodpeckers nest in both the live and dead wood of a variety of trees, including cottonwoods (Populus spp.) and willows (Salix spp.), in the trunks of the Joshua Tree, or in the dead flowering stalks of other species of yucca or agave (Grinnell and Miller 1944, Lowther 2001, Unitt 2004, McKernan unpubl. data).