taxus), long-tailed weasel (Mustela frenata), western spotted skunk (Spilogale gracilis), and striped skunk (Mephitis mephitis). Non-predatory mammals known to be present include Rocky Mountain elk (Cervus elaphus), mule deer (Odocoileus hemionus), raccoon (Procyon lotor), porcupine (Erethizon dorsatum), black-tailed jackrabbit (Lepus californicus), desert cottontail, (Sylvilagus auduboni), white-throated woodrat (Neotoma albigula), Botta's pocket gopher (Thomomys bottae), Colorado chipmunk (Neotamias quadrivittatus), pinyon mouse (Peromyscus truei), and deer mouse (Peromyscus spp.). Sensitive mammalian species known to be present at the Caja include Gunnison's prairie dog (Cynomys gunnisoni). A small herd of wild horses (consisting of approximately 50 individuals) lives year round on the plateau. Birds of prey found in or near the Caja include bald eagle (Haliaeetus leucocephalus), golden eagle (Aquila chrysaetos), red-tailed hawk (Buteo jamaicensis), ferruginous hawk (Buteo regalis), Swainson's hawk (Buteo swainsonii), American kestrel (Falco sparverius), and peregrine falcon (Falco peregrinus anatum). Other resident non-migratory birds include Merriam's turkey (Meleagris gallopavo), pinyon jay (Gymnorhinus cyanocephalus), hairy woodpecker (Picoides villosus), and scaled quail (Callipepla squamata). Migratory birds found in or near the Caja include turkey vulture (Cathartes aura), killdeer (Charadrius vociferus), loggerhead shrike (Lanius ludovicianus), common nighthawk (Chordeiles minor), mourning dove (Zenaida macroura, broad-tailed hummingbird (Selasphorus platycercus), ladder-backed woodpecker (Picoides scalaris), downy woodpecker (Picoides pubescens), northern flicker (Colaptes auratus), gray flycatcher (Empidonax wrightii), Say's phoebe (Sayornis saya), ash-throated flycatcher (Myiarchus cinerascens), Cassin's kingbird (Tyrannus vociferans), plumbeous vireo (Vireo plumbeus), horned lark (Eremophila alpestris), violet-green swallow (Tachycineta thalassina), northern rough-winged swallow (Stelgidopteryx serripennis), blue-gray gnatcatcher (Polioptila caerulea), western bluebird (Sialia mexicana), mountain bluebird (Sialia currucoides), Townsend's solitaire (Myadestes townsendi), American robin (Turdus migratorius), American pipit (Anthus rubescens), black-throated gray warbler (Setophaga nigrescens), western tanager (Piranga ludoviciana), chipping sparrow (Spizella passerina), lark sparrow (Chondestes grammacus), western meadowlark (Sturnella neglecta), and brown-headed cowbird (Molothrus ater). Waterfowl using the Rio Grande corridor include Canada goose (Branta canadensis), mallards (Anas platyrhynchos), northern pintails (Anas acuta), and American wigeon (Mareca americana). Sensitive bird species known to be present at the Caja include bald eagles, peregrine falcons, and gray vireos. Common reptiles include collared lizards (Crotaphytus collaris), roundtail horned lizard (Phrynosoma modestum), striped whipsnake (Masticophis taeniatus), and western diamondback rattlesnake (Crotalus atrox). Sensitive reptilian species include the desert kingsnake (Lampropeltis getula splendida). Human use and management Prehistoric Puebloans built dozens of village sites across the Caja del Rio and Pajarito plateaus. In contrast to its western neighbor, however, the canyon walls of the Caja are frequently made of basalt, rather