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The influence of human harvest on evolution of secondary sexual characteristics has implications for sustainable management of wildlife populations. The phenotypic consequences of selectively removing males with large horns or antlers from ungulate populations have been a topic of heightened concern in recent years. Harvest can affect size of horn‐like structures in two ways: (a) shifting age structure toward younger age classes, which can reduce the mean size of horn‐like structures, or (b) selecting against genes that produce large, fast‐growing males. We evaluated effects of age, climatic and forage conditions, and metrics of harvest on horn size and growth of mountain sheep (Ovis canadensis ssp.) in 72 hunt areas across North America from 1981 to 2016. In 50% of hunt areas, changes in mean horn size during the study period were related to changes in age structure of harvested sheep. Environmental conditions explained directional changes in horn growth in 28% of hunt areas, 7% of which did not exhibit change before accounting for effects of the environment. After accounting for age and environment, horn size of mountain sheep was stable or increasing in the majority (~78%) of hunt areas. Age‐specific horn size declined in 44% of hunt areas where harvest was regulated solely by morphological criteria, which supports the notion that harvest practices that are simultaneously selective and intensive might lead to changes in horn growth. Nevertheless, phenotypic consequences are not a foregone conclusion in the face of selective harvest; over half of the hunt areas with highly selective and intensive harvest did not exhibit age‐specific declines in horn size. Our results demonstrate that while harvest regimes are an important consideration, horn growth of harvested male mountain sheep has remained largely stable, indicating that changes in horn growth patterns are an unlikely consequence of harvest across most of North America.

Wild sheep in North America were abundant and widely distributed prior to European exploration and settlement. By the early twentieth century unregulated hunting, forage competition with domestic livestock, introduced diseases, and human encroachment had dramatically reduced bighorn sheep (Ovis canadensis) numbers and distribution in the western US, southern Canada, and mainland and Baja Peninsula Mexico. The restoration of bighorn sheep has been a remarkable conservation success, as a result of efforts by wildlife and land management agencies, conservation organizations, private landowners and other stakeholders. These efforts have been largely underwritten by pro-hunting conservation organizations.

Ungulate populations in desert environments are thought to be regulated by precipitation. Pronghorn (Antilocapra americana) populations in Trans-Pecos, Texas, USA, experienced a 70% decline between 1977 and 2001. The causative factors associated with the decline are unknown but appear to be related to drought. We evaluated the relationships between pronghorn abundance and productivity and precipitation (i.e., raw precipitation, Palmer Drought indices) for the Trans-Pecos district of Texas from 1977 to 2004. Pronghorn productivity (range = 305–4,407) and abundance (range = 5,061–17,266) showed high variability. Precipitation was also highly variable, ranging from 18 cm to 57 cm. Pronghorn abundance was positively influenced by precipitation indices (R = 0.790, P < 0.001). The relationship between fawn production and raw precipitation (R = 0.869, P < 0.001) suggested that fawn production may be more closely related to immediate moisture conditions, whereas pronghorn abundance was more influenced by...

Desert bighorn sheep (Ovis canadensis) have been extirpated from much of their historical range in the Chihuahuan Desert. Understanding their dietary preferences in the Chihuahuan Desert is integral to their successful restoration. We evaluated differences (sexual, temporal, and spatial) in the diets of desert bighorn sheep from Elephant Mountain Wildlife Management Area in the Chihuahuan Desert of western Texas by using microhistological analysis of 432 fecal pellet groups (209 rams, 209 ewes, 14 lambs) collected every 2 weeks between September 1998 and August 2000. Ninety-four plant species were identified; bighorn sheep diets consisted of 50% browse, 35% forbs, 11% grasses, and 4% succulents. Diets of rams and ewes did not differ annually. Diets differed seasonally (P , 0.05); forbs prevailed in diets of rams during winter. Diets of bighorn sheep from Elephant Mountain were compared to previously determined diets from the Beach, Baylor, and Sierra Diablo mountains. There were significant differences among female diets between Elephant Mountain and Beach Mountain during winter and the Sierra Diablo Mountains in fall, winter, and summer. Dietary overlap was greatest among desert bighorn sheep at Elephant Mountain and the Sierra Diablo Mountain populations (57.6%), followed by Baylor Mountain (55.7%) and Beach Mountain (52.0%). Dietary overlap among all ranges was highest in the browse component (53%), followed by forbs (23%), grasses (16%), and succulents (8%). RESUMEN—El borrego cimarron del desierto (Ovis canadensis) ha sido extirpado de gran parte de su distribucion historica en el desierto Chihuahuense. El conocimiento de sus preferencias alimenticias en el desierto Chihuahuense es integral para la restauracion exitosa de esta especie. Hemos evaluado diferencias (sexuales, temporales y espaciales) en las dietas del borrego cimarron del desierto en Elephant Mountain Wildlife Management Area en el desierto Chihuahuense del oeste de Texas utilizando el analisis microhistologico de 432 grupos de heces fecales (209 machos, 209 hembras, 14 cro ´as), colectadas cada 2 semanas entre septiembre 1998 y agosto 2000. Noventa y cuatro especies de plantas fueron identificadas; las dietas de borrego cimarron consistieron de 50% de arbustivas, 35% de herbaceas, 11% de gramo ´neas y 4% de suculentas. Las dietas de machos y hembras no se diferenciaron anualmente. Las dietas difirieron por temporada (P , 0.05); las hierbas prevalecieron en las dietas de machos durante el invierno. Las dietas del borrego cimarron en Elephant Mountain fueron comparadas con las dietas que habo ´an sido determinadas anteriormente en las sierras Beach, Baylor, y Sierra Diablo. Hubo diferencias significativas entre las dietas de las hembras de Elephant Mountain y Beach Mountain durante el invierno y el verano. La similitud de dietas fue mayor entre las poblaciones de borregos de Elephant Mountain y Sierra Diablo Mountain (57.6%) seguida por Baylor Mountain (55.7%) y Beach Mountain (52.0%). La similitud de las dietas entre todas las sierras fue mas alta en los componentes arbustivos (53%), seguido por herbaceas (23%), gramo ´neas (16%) y suculentas (8%).

Montezuma quail (Cyrtonyx montezumae) are one of the least understood upland game birds in North America. The lack of ecological studies on Montezuma quail may be attributed to the inability of researchers to capture the secretive bird. We evaluated techniques that are commonly used for capturing other upland game of North America including funnel traps, trained dogs and hand-nets, audio calls, portable mist nets, and night-netting in the Chihuahuan Desert of Texas, USA, 2000–2001. The modified mist net was the most successful technique employed for capturing nonradiotagged Montezuma quail; however, its application may be limited to grassland and savannah communities. Researchers attempting to capture Montezuma quail should employ a variety of capture techniques and then bolster sample sizes using night-netting.

Little information is known about the foraging habitat of Montezuma quail (Cyrtonyx montezumae) in Texas, USA. We compared habitat characteristics of foraging and nonforaging areas to identify trends in habitat attributes across sites with varying levels of quail use on Elephant Mountain Wildlife Management Area in Brewster County, Texas, USA, during May–August 2001. We delineated foraging and nonforaging areas using a system of parallel transects (100 m apart) that spanned the length of the grassland and covered the entire area. We walked transects every 3–5 days searching for signs of feeding (i.e., diggings). We documented a higher mean density of Allium spp. plants in foraging (95% CI: 12.1 ± 4.3 plants/m2) than nonforaging areas (95% CI: 0.8 ± 0.6 plants/m2). Foraging areas also exhibited a greater mean slope (95% CI: 22.6 ± 2.9% vs. 8.0 ± 2.1%). However, species richness, diversity, and equitability were similar between the foraging (23, 6.5, and 0.3, respectively) and nonforaging area (29,...

Passive and active infrared camera systems and, more recently, videography have been used in wildlife research to assist in data collection. Traditional camera systems can be expensive and labor-intensive, and are limited in operation time by film length and battery life. Current camera systems are neither computer- nor network-oriented and do not allow for near real-time retrieval and storage of data. We describe a web-based, digital camera system for monitoring wildlife in remote, inaccessible environments. Between February 2002 and December 2003, our web-based camera system collected 486 digital photographs of west Texas wildlife. The key advantage of our camera system is that it allows for unobtrusive monitoring of secretive and often unobservable species in their natural habitat. Because our system is web-based, high-resolution photographs of wildlife can be posted on a web page for viewing, offering a unique teaching tool for grade school and university students who may not have the opportunity to visit these remote, inaccessible areas. Although our camera system was expensive ($12,000 U.S.), it offers a self-sustaining technique for monitoring wildlife in remote regions that allows for easy data retrieval and storage.