Because of significant declines in mule deer (Odocoileus hemionus) populations across New Mexico, USA, we investigated survival of fawns in north-central New Mexico, USA. We captured 19 fawns, 34 fawns, and 47 fawns in 2002, 2003, and 2004, respectively, and used fawn morphological measurements, habitat characteristics, and adult female (hereafter ''female'') condition to model preweaning fawn survival. Survival was 0.0, 0.12, 0.52 for 2002, 2003, and 2004, respectively, and was related to birth mass (v 1 2 ¼ 9.5,summer precipitation (v 1 2 ¼ 37.5, P , 0.001), and winter precipitation (v 1 2 ¼ 32.0, P , 0.001). Total ingesta-free body fat of females (b ¼ 3.01, SE ¼ 0.75; odds ratio ¼ 20.19, 95% CI ¼ 4.64-87.91) and birth mass of fawns (b ¼ 1.188, SE ¼ 0.428; odds ratio ¼ 3.38, 95% CI ¼ 1.42-7.59) were the best predictors of survival of individual fawns, although few of the logistic models differed in model selection criteria. Fawn survival in north-central New Mexico was driven by an interaction of total and seasonal precipitation and its effect on plant production, consequential effects on female nutrition, and ultimately, fawn birth attributes. Habitat conditions were so poor throughout north-central New Mexico during 2002 and 2003 (and likely during other drought yr) that, based upon birth attributes, few fawns could have survived regardless of proximate causes of mortality. In 2004, precipitation enhanced security cover, maternal body condition, birth attributes and, thus, survival of fawns. However, more habitat enhancements are needed to improve the nutritional quality of mule deer habitats in north-central New Mexico and further enhance maternal and fawn condition to recover mule deer populations in this region. ( JOURNAL OF WILDLIFE MANAGEMENT 71(3):884-894; 2007)

From December 2001 to December 2004 we monitored 30–44 adult female mule deer (Odocoileus hemionus) annually to assess the factors affecting survival and cause‐specific mortality. We found adult female survival of 0.63 (SE = 0.08), 0.90 (SE = 0.05), and 0.91 (SE = 0.04), 2002–2004, respectively. Starvation was the most common cause of mortality, accounting for 11/23 mortalities. Mean ingesta‐free body fat (IFBF) levels of adult females in December were low (6–9%), despite few (0–13%) lactating adult females, indicative of extremely nutritionally deficient summer—autumn ranges throughout the study site. A priori levels of IFBF and rump body condition scores (rBCS) were higher in deer that survived the following year regardless of cause of mortality. Logistical analysis indicated that models containing individual body fat, rBCS, mean population body fat, winter precipitation, precipitation during mid‐ to late gestation, and total annual precipitation were related (x2 ≥ 9.1; P ≤ 0.003) to deer survival, with individual IFBF (β =‐0.47 [SE = 0.21]; odds ratio = 0.63 [0.42‐0.94]) and population mean IFBF (β = ‐1.94 [SE = 0.68]; odds ratio = 0.14 [0.04‐0.54]) the best predictors; with either variable, probability of dying decreased as fat levels increased. Fawn production was low (2–29 fawns/100 ad F) and, combined with adult survival, resulted in estimated population rates of increase of ‐35%, ‐5%, and +6% for 2002–2004, respectively. Deer survival and population performance were limited in north‐central New Mexico, USA, due to poor condition of deer, likely a result of limited food resulting from both drought and long‐term changes in plant communities. Precipitation during mid‐ to late gestation was also important for adult female survival in north‐central New Mexico.

Productivity of mule deer (Odocoileus hemionus Raf.) populations is closely linked to individual nutritional condition. We modeled body fat of individual does as a function of vegetation cover, composition, and water characteristics of their annual, summer, and winter home ranges in north-central New Mexico. We also modeled home range size as a function of the same characteristics. Levels of body fat were most closely and negatively related to the amount of pinyon-juniper in an individual deer's annual home range (F 1,21 5 7.6; P 5 0.012; r 2 5 0.26). Pinyon-juniper types provided little (combined ground cover of preferred forbs and shrubs 5 5.7%) mule deer forage but were included in home ranges in excess of their availability on the landscape, likely because of security cover attributes. Proportion of grasslands in home ranges was most strongly related to both annual (F 1,23 5 4.9; P 5 0.037; r 2 5 0.18) and summer (F 2,25 5 5.7; P 5 0.009; r 2 5 0.31) home range sizes, and home ranges increased as the grassland component increased, indicating that this habitat type was providing little value to mule deer. Grassland (0.2% combined cover of preferred forb and shrub) and montane conifer (3.2% ground cover of preferred forb and shrub) habitat types similarly lacked preferred mule deer food, and grasslands also lacked cover. Most immediate gains in mule deer habitat in north-central New Mexico may be attained by management of pinyon-juniper communities to increase forage quantity and quality while maintaining cover attributes. Gains can also be realized in grasslands, but here management must establish both cover and forage. Resumen La productividad de las poblaciones de venado Bura (Odocoileus hemionus Raf.) esta estrechamente relacionada a la condición nutricional individual. Modelamos la grasa corporal de las hembras en función de la cobertura vegetal, composición y las características del agua de los pastizales anuales de verano e invierno de su territorio en la región norte-centro de New Mexico y tambie´n modelamos el tamañ o de su territorio en función de las mismas características. Los niveles de grasa corporal estuvieron más estrecha y negativamente relacionados a la cantidad de ''Pinyon-juniper'' en el territorio anual individual del venado (F 1,21 5 7.6; P 5 0.012; r 2 5 0.26). Los tipos de ''Pinyon-juniper'' suministraron (combinado con la cobertura de las hierbas y arbustos preferidos 5 5.7%) poco forraje al venado Bura, pero estuvieron incluidos en el su territorio de pastizal en exceso en relación a su disponibilidad en el paisaje, probablemente por los atributos de seguridad de la cobertura. La proporción de zacatal en el pastizal territorial estuvo más estrechamente correlacionada al tamañ o de los pastizales territoriales anual (F 1,23 5 4.9; P 5 0.037; r 2 5 0.18) y de verano (F 2,25 5 5.7; P 5 0.009; r 2 5 0.31), y los territorios se incrementaron conforme el componente zacatal aumentó, indicando que este tipo de hábitat fue de poco valor para el venado Bura. Los tipos de hábitat de zacatal (0.2%...