White Color Phase of the Swift Fox, Vulpes velox

While live-trapping Swift Foxes (Vulpes velox) in northwestern Texas, we captured and radio-collared a Swift Fox that exhibited a white pelage and light blue eyes. Although white color phases and light blue eyes have been reported for other canid species, this is the first documentation for Swift Foxes

Factors limiting productivity of the Central Arctic Caribou Herd of Alaska

Many biotic and abiotic factors can limit productivity and growth of caribou (Rangifer tarandus) herds, but limiting factors typically vary by region. Identifying limiting factors may help to indicate which seasons are of relative importance to a caribou herd and possibly to suggest general life history strategies. Using regression techniques, we found that despite previous suggestions, net productivity of Alaska’s Central Arctic Caribou Herd (CAH) did not respond to early summer forage biomass or summer insect severity from the previous year. Abiotic factors that did have apparent effects on CAH productivity included early fall snow deposition, winter snow condition, and spring snow ablation. To achieve a suitable weight for conception, caribou of the CAH may exhibit a seasonal time-minimizing foraging strategy by moderating weight gain during the warm summer insect season and feeding more intensively during the insect-free weeks before the autumn rut. A long-term trend of the Northern Hemisphere annular mode (NAM) may be linked to anthropogenic climate change and may have negative implications for the future success of the CAH

Wolf Interactions with Non-prey

WOLVES SHARE THEIR ENVIRONMENT with many animals besides those that they prey on, and the nature of the interactions between wolves and these other creatures varies considerably. Some of these sympatric animals are fellow canids such as foxes, coyotes, and jackals. Others are large carnivores such as bears and cougars. In addition, ravens, eagles, wolverines, and a host of other birds and mammals interact with wolves, if only by feeding on the remains of their kills

Swift Fox, Vulpes velox, Den Located Next to a Railroad Track in Northwestern Texas

Swift Fox (Vulpes velox) dens are typically found in areas were the vegetation is sparse, in loam soils, and with unobstructed views of the surrounding area. In 2002 a Swift Fox in northwest Texas was found in a unique den situated at the base of a hill with the entrance within 1 m of an active railroad track. Use of a den in such proximity to railroad tracks has never been previously reported

Comparisons and Trends in White-tailed Deer, Odocoileus virginianus, Body Fat in Northeastern Minnesota, 1974-1990

The relationships among locations of body fats have not been thoroughly examined in White-tailed Deer (Odocoileus virginianus). We measured bone marrow fat (n = 2995), back fat (n = 1018), kidney fat (n = 2076), and xiphoid fat (n = 1246) levels of White-tailed Deer kills from Cook and Lake counties in northeastern Minnesota during 1974-1990. For each dead deer we determined age, sex, date, and causes of mortality. All of the fat measures were correlated to varying degrees. Generally all fat measurements peaked in late autumn and subsequently began declining and reached their lowest levels in May. Fat content was negatively correlated with winter severity. Causes of mortality included predation, poaching, accidental, unknown, and auto-collisions. Predated animals had lower bone marrow (-7.42 ± 3.92) and 0.165 ± 2.30 times lower back fat and had higher amounts of kidney fat than those killed by vehicles (0.86 ± 0.43)

Swift Fox, Vulpes velox, Den Use Patterns in Northwestern Texas

Predator avoidance may be a reason why Swift Foxes (Vulpes velox) are one of the most burrow-dependent canids in North America. Typically Swift Foxes have multiple dens, which they frequently move among. As part of a larger study to reduce Coyote (Canis latrans) related mortalities on Swift Foxes, we installed artificial escape dens in areas occupied by Swift Foxes on Rita Blanca National Grassland, Dallam County, Texas. For this paper, our objective was to determine the effects of artificial escape dens on Swift Fox den use patterns. From January 2002 to August 2004 we captured, radio-collared, and monitored 55 Swift Foxes. We documented annual number of dens used, rate of den use (fidelity), distance between dens, den area, and den sharing. We compared treated (artificial dens installed) and untreated (no artificial dens) areas but found no differences in annual number of dens (P = 0.64; mean = 8), rate of den use (P = 0.96; mean = 35%), mean distance between dens (P = 0.99; mean = 2,311 m), den area (P = 0.55; mean = 5.72 km2), or den sharing (P = 0.46; mean = 42% of time). We did not observe an effect of artificial escape dens on Swift Fox den use patterns probably because artificial escape dens were designed for temporary escape cover rather than diurnal den use

Physical Characteristics, Hematology, and Serum Chemistry of Freeranging Gray Wolves, Canis lupus, in Southcentral Alaska

Examination of morphometric characteristics and blood parameters has become a widely used tool for assessing the physiological and nutritional status of wild and captive animals. During 1976 through 1984, 155 Gray Wolves (Canis lupus) were chemically immobilized in south-central Alaska. Of those, we obtained physical measurements from 132 and blood samples from 121 individuals. Also, 208 carcasses of harvested and dead radiocollared Wolves were weighed and measured. We obtained blood samples from three of the fresh carcasses. We measured age, body weight, skull length and width, and upper and lower canine length. We analyzed blood serum for Ca, P, Fe, chlorides, creatinine, glucose, lactic dehydrogenase, alkaline phosphatase, glutamic oxalic transaminase, triglyceride, beta globulin, serum urea nitrogen, and uric acid. We obtained packed cell volume and hemoglobin values from whole blood. We classified samples by season, sex, and age. Seasonal differences were observed for physical measurements, packed cell volume, alkaline phosphatase, and serum urea nitrogen. Age differences were observed for physical measurements, hemoglobin, packed cell volume, alkaline phosphatase, P, Ca, creatinine, serum urea nitrogen, and percent femur bone marrow fat. However, differences among sexes were observed for physical measurements only. These data provide a baseline for physical condition, hematology, and serum chemistry for free-ranging Gray Wolves

Habitat-Distribution Modeling of a Recolonizing Black Bear, Ursus americanus, Population in the Trans-Pecos Region of Texas

Black Bears (Ursus americanus) were once widespread across Texas, but their numbers were reduced in the early 1900s. Recolonization of the Trans-Pecos region of Texas has occurred via bears migrating northward from Mexico. Recent bear sightings have increased in this area. This could be an indication that the population in Texas is beginning to recover, but the population will continue to expand only if there is suitable habitat to occupy. To help identify suitable habitat and restoration areas, we developed a predictive habitat-distribution model by using records of Black Bear sightings from 1996 to 2003 to map the species' distribution. Using Bayesian statistics, we modeled the probability of occurrence of Black Bears in the Trans-Pecos region based on sighting locations. We used GIS layers for land use/landcover, elevation, water sources, and road networks to obtain covariates in our modeling. We used a 10-fold cross-validation to test the effectiveness of using sighting data. Our results indicated a negative association with bare areas, agriculture, and grassland landcovers. In addition, southern aspect, elevation, distance to water, slope, and western aspect also influenced suitable habitat. Both the original and validation datasets correctly classified bear sightings 93.9% and 93.7% of the time, respectively. Our model can be used to target restoration efforts to enhance the ability of the Black Bear to expand in the Trans-Pecos region. It can also identify private landowners most likely to be affected by the expansion of Black Bears for education and cooperative efforts

Distance-Based Habitat Associations of Northern Bobwhites in a Fescue-Dominated Landscape in Kansas

Northern bobwhites (Colinus virginianus) have a wide distribution across North America which influences its’ associations with habitats in a variety of landscapes. We used radio-marked bobwhites and Euclidean distance to characterize land cover associations of bobwhites at generalized level 1 and specific level 2 land cover classifications during the reproductive (15 Apr-14 Oct) and covey (15 Oct-14 Apr) periods in southeastern Kansas from 2003 to 2005. Habitat associations occurred during the reproductive (Wilkes’ k 1⁄4 0.04, F6,36 1⁄4 143.682, P , 0.001) and covey (Wilkes’ k 1⁄4 0.056, F6, 29 1⁄4 81.99, P , 0.001) periods. Ranking of the reproductive period habitats indicated bobwhites preferred locations in close proximity to fescue (Festuca spp.) over all other habitats. Coveys preferred locations in close proximity to woody cover. Bobwhites were found to associate with specific habitats at the level 2 land cover classification during the reproductive (Wilkes’ k 1⁄4 0.006, F16, 26 1⁄4 284.483, P , 0.001) and covey (Wilkes’ k 1⁄4 0.004, F16, 19 1⁄4 276.037, P , 0.001) periods. Bobwhites preferred locations in close proximity to fescue pastures and roads equally over all other habitats during the reproductive period. Coveys preferred locations in close proximity to roads and Conservation Reserve Program lands during the covey period. Fescue pastures may be avoided by bobwhites during the covey period, provided adequate cover is not provided, but bobwhites are strongly associated with them during the reproductive period because they meet nesting and brooding needs not met by other habitats

ACCURACY AND PRECISION OF ESTIMATING AGE OF GRAY WOLVES BY TOOTH WEAR

We evaluated the accuracy and precision of tooth wear for aging gray wolves (Canis lupus) from Alaska, Minnesota, and Ontario based on 47 known-age or known-minimum-age skuIIs. Estimates of age using tooth wear and a commercial cementum annuli-aging service were useful for wolves up to 14 years old. The precision of estimates from cementum annuli was greater than estimates from tooth wear, but tooth wear estimates are more applicable in the field. We tended to overestimate age by 1-2 years and occasionaIIy by 3 or 4 years. The commercial service aged young wolves with cementum annuli to within ± 1 year of actual age, but under estimated ages of wolves 2:9 years old by 1-3 years. No differences were detected in tooth wear patterns for wild wolves from Alaska, Minnesota, and Ontario, nor between captive and wild wolves. Tooth wear was not appropriate for aging wolves with an underbite that prevented normal wear or severely broken and missing teeth