We used sightability models with aerial counts to estimate regional abundance of desert bighorn sheep (Ovis canadensis) in southwestern Arizona during 1992–2012. Because of incomplete spatial and temporal coverage of surveys, we integrated sightability estimates using Bayesian state‐space models. Although some game management units (GMUs) exhibited negative average growth rates during this period, temporal variability in growth was large. The combination of temporal variability and statistical uncertainty in the sightability estimates led to the selection of a regional model having zero mean growth from initial abundance. Hence, the model indicated a relatively stable population of desert bighorn sheep in southern Arizona, beginning with approximately 2,900 bighorn sheep in 1992 to the current number of approximately 2,300 sheep (2012). Our method provides statistically valid estimates of overall regional abundance not otherwise possible given the incomplete spatial coverage of surveys. Additionally, results have implications for other studies, common in wildlife management, where managers seek to integrate information across surveys with partial time‐series. © 2014 The Wildlife Society.

The Sonoran pronghorn (Antilocapra americana sonoriensis) is one of the most endangered ungulates in North America. The use of water to improve its habitat in southwestern Arizona has been limited in part because published reports claimed these desert ungulates do not use freestanding water. Because free‐standing water has been beneficial to habitat improvement of other desert ungulates, we set up cameras at anthropogenic waters to see if they were used by pronghorn, examined literature and agency files related to Sonoran pronghorn and water, and interviewed ranchers who have lived and managed livestock in Sonoran pronghorn habitat since the 1930s regarding their observations of pronghorn use of livestock waters. Using direct observation and photographic evidence, we documented Sonoran pronghorn drinking freestanding water. Published reports claiming that Sonoran pronghorn do not drink were erroneous. Ranchers, agency files, and biologists from numerous state and federal agencies documented Sonoran pronghorn drinking. Federal and state agencies should be aggressive in examining how water developments can be used to assist in recovery of endangered Sonoran pronghorn.

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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 pronghorn did not use vegetation associations similarly to each other (χ422=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 (=1,321 km2) than those that preferred PVC (=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).

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