We investigated home-range and habitat preferences of Sonoran pronghorn (Antilocapra americana sonoriensis) from 1994 to 2002 as part of a recovery program. Home-range size varied from 43–2,873 km2, with an average of 511± 665.3 (SD) km2 (n=22). We classified vegetation into 3 associations: creosote (Larrea tridentata)–bursage (Ambrosia spp.; CB), palo verde (Cercidium spp.)–mixed cacti (PV), or palo verde–chain fruit cholla (Opuntia fulgida; PVC). Individual prong-horn did not use vegetation associations similarly to each other (χ242 = 779, P< 0.001). Most pronghorn (n=17) used PVC more than expected and used CB and PV less than or equal to availability. Those pronghorn (n=5) that used CB more than expected or equal to availability had significantly larger home ranges (x̄= 1,321 km2) than those that preferred PVC (x̄ =272.7 km2, t=86, P=0.028). We pooled locations of all pronghorn to determine the influence of season and range condition (based on rainfall) on vegetation association preference. Range condition and season influenced vegetation association use by pronghorn. Pronghorn used CB more than expected during the cool season of 1997–1998. Pronghorn used washes more than expected in all seasons and range conditions (χ2=277, P< 0.001). This information is useful to managers planning recovery actions (i.e., forage enhancement, water development, and captive breeding).
Antilocapra americana sonoriensis
chain fruit cholla
vegetation association preference