We experimentally evaluated alternative techniques of attaching radiotransmitters to captive white-winged doves (Zenaida asiatica) in Kingsville, Texas during 1998. Our evaluation consisted of monitoring physiological, pathological, and behavioral parameters in doves subjected to 6 radiotransmitter attachments (backpack harnesses, adhesive, subcutaneous implants, intracoelomic implants, subcutaneous surgeries without implantation, intracoelomic surgeries without implantation). We analyzed physiological parameters across 2 pretreatment and 4 post-treatment periods using a model-selection approach of mixed-effect models. Birds did not differ in physiological variables among treatment groups and a control. Time-activity budgets analyzed using nonparametric Friedman's tests did not differ in any activity category among treatment groups and a control. Subcutaneous implants were the most effective method of attachment based on retention rates, lack of mechanical difficulties associated with external attachment techniques, and minimum levels of pathology reported following necropsies.

The estimation of large-ungulate population size involves a systematic search of occupied habitat and visual observation of individuals. In this study we determined the probability that forward-looking infrared radiometer (FLIR) mounted in a fixed-wing airplane would detect and verify California bighorn sheep (Ovis canadensis californiana). The study area included the highly dissected rhyolite canyons of southwestern Idaho. All age and sex classes could be detected with the FLIR. Flying at 600 m above ground level (AGL), FLIR could distinguish bighorn sheep from other ungulates and large mammals (i.e., pronghorn [Antilocapra Americana], mule deer [Odocoileus hemionus], livestock, and mountain lion [Felis concolor]). Image clarity and the ability to circle the animal without disturbance allowed determination of male age classes for use in setting harvest of available rams. Bighorn sheep could be detected in all habitats used within the study area. Data were collected over 3 years, with probability of detection of 89%. A set search pattern allowed consistent detection rates between sensor operators, airplane type, or among years. This study identified variables that influence sighting probability using FLIR. The use of a FLIR mounted on an airplane flying at 600 m AGL has advantages over surveys using visual observations from airplanes or helicopters; those advantages include reduced stress to the animals, reduced violations of assumptions of sightability models, and reduced hazard to observers.

Knowledge of animal behavior and resource selection is most accurate when direct observations of animals are made. It is impractical, if not impossible, however, to directly and efficiently observe free-ranging animals for extended periods of time without affecting their behavior. To help address these difficulties, we designed a miniature animal-mounted wireless video camera system that remotely records a portion of the sighting field of white-tailed deer (Odocoileus virginianus). The system consisted of a miniaturized charge-coupled-device (CCD) video camera, a miniaturized UHF transmitter (channel 30 or 42), a light-activated on-off relay circuit, protective plastic housing, a combination VCR/TV, a UHF TV antenna on a 9.1-m mast, and 12 9V lithium-ion DC batteries on a leather neck collar. The real-time color video image was transmitted up to 500 m and recorded on VHS tape. Using this system, we videotaped daytime observations of white-tailed deer food choices for up to 2 weeks. We assessed food choices from 70 hours of video footage from 1 antlered deer recorded during fall 2002 to demonstrate the utility of the technique. Our video system allowed us to monitor detailed food choices without the logistical difficulties present in direct observational studies. This tool could prove useful in studying detailed behavioral observations of captive animals; future development of electronic components could offer applications to free-ranging deer.

The United States Fish and Wildlife Service uses the Parts Collection Survey (PCS) to monitor migratory bird populations through examination of parts collected by hunters. An important new addition to the PCS is the inclusion of migratory shorebirds and upland game birds (MSUGB) in the survey. However, age and sex keys have been developed for only 2 MSUGB species. For the survey to be effective, keys for all MSUGB need to be developed. To that end, we examined collected specimens and museum mounts to develop an age and sex key for common moorhens (Gallinula chloropus) based on various quantitative and qualitative morphological characteristics. Culmen-shield width proved to be the best qualitative characteristic for aging moorhens. Ninety-three percent of adults had culmen-shield widths >10.4 mm while only 4% of juveniles had shield widths >10.4 mm. Bill length was also a good predictor of age. Wing-covert color and degree of point on tertial tips were the best qualitative characteristics for aging common moorhens. Juveniles tended to have olive-brown dorsal wing coverts and highly pointed tertials while adults usually had slate gray-black coverts and rounded tertials. Only one characteristic, wing chord, showed promise for sexing common moorhens. Males of both age classes tended to have longer wing-chord lengths than females of both age classes. Managers can use culmenshield width to accurately age harvested common moorhens. However, damage to soft parts during shipping may render culmen shields less useful. Color of dorsal coverts and degree of point on tertial tips may be more practical for aging moorhens and, when used in combination, are highly accurate. Managers can use wing chord as a reliable indicator of sex; however, we recommend that specimens first be aged to increase the reliability.

The greatest promise of radiotelemetry always has been a better understanding of animal movements. Telemetry has helped us know when animals are active, how active they are, how far and how fast they move, the geographic areas they occupy, and whether individuals vary in these traits. Unfortunately, the inability to estimate the error in animals' utilization distributions (UDs), has prevented probabilistic linkage of movements data, which are always retrospective, with future management actions. We used the example of the harvested population of polar bears (Ursus maritimus) in the Southern Beaufort Sea to illustrate a method that provides that linkage. We employed a 2-dimensional Gaussian kernel density estimator to smooth and scale frequencies of polar bear radio locations within cells of a grid overlying our study area. True 2-dimensional smoothing allowed us to create accurate descriptions of the UDs of individuals and groups of bears. We used a new method of clustering, based upon the relative use collared bears made of each cell in our grid, to assign individual animals to populations. We applied the fast Fourier transform to make bootstrapped estimates of the error in UDs computationally feasible. Clustering and kernel smoothing identified 3 populations of polar bears in the region between Wrangel Island, Russia, and Banks Island, Canada. The relative probability of occurrence of animals from each population varied significantly among grid cells distributed across the study area. We displayed occurrence probabilities as contour maps wherein each contour line corresponded with a change in relative probability. Only at the edges of our study area and in some offshore regions were bootstrapped estimates of error in occurrence probabilities too high to allow prediction. Error estimates, which also were displayed as contours, allowed us to show that occurrence probabilities did not vary by season. Near Barrow, Alaska, 50% of bears observed are predicted to be from the Chukchi Sea population and 50% from the Southern Beaufort Sea population. At Tuktoyaktuk, Northwest Territories, Canada, 50% are from the Southern Beaufort Sea and 50% from the Northern Beaufort Sea population. The methods described here will aid managers of all wildlife that can be studied by telemetry to allocate harvests and other human perturbations to the appropriate populations, make risk assessments, and predict impacts of human activities. They will aid researchers by providing the refined descriptions of study populations that are necessary for population estimation and other investigative tasks.

Twelve adult African fish eagles (Haliaeetus vocifer) were captured on water using a floating fish “snare vest” on Lake Victoria near Entebbe and Lake Mburo in Uganda. The snare vest comprised 8–12 monofilament nylon snares attached to a floating 15–25-cm Nile tilapia (Oreochromis niloticus). Capture success was 17% of birds that struck the bait at Lake Mburo and 10% at Lake Victoria. The success rate was dependent on multifactorial local site conditions, operator experience, and snare design. The methods described are the first detailed report on the capture of this species, and the snare vest highlights subtle variations in technique from those reported for the capture of other large eagle species.

Mexican gray wolves (Canis lupus baileyi) are the smallest subspecies of North American gray wolves (Canis lupus), and identification of Mexican wolf scats could be confused with those of sympatric coyotes (Canis latrans). We used DNA analysis (molecular scatology) to differentiate scats (n = 203) of free-ranging Mexican gray wolves and coyotes and compared the results to traditional field methods (i.e., diameter, location, and sign) and odor used for identifying scats of the 2 species. We then used the scats whose species identifications were confirmed with DNA analysis to evaluate discriminant analysis for classifying scats using 3 measurements—diameter, mass, and length. Forty-nine (24%) of the field-collected scats (n = 203) tested provided amplifiable DNA and were determined to comprise 28 scats deposited by Mexican wolves and 21 deposited by coyotes. Scats identified with DNA analysis to the 2 species had a 79% diameter overlap (Mexican wolf 16.3–35.8 mm; coyote 17.4–27.8 mm), and scats ≥28 mm in diameter were Mexican wolf scats. There was a significant difference (t = −2.28; P < 0.05) between diameter means for the 2 species (Mexican wolf x̄ = 26.0 mm; coyote x̄ = 22.8 mm). Of 45 scats that would have been field-identified as deposited by Mexican wolves based on location and odor criteria, DNA analysis indicated that 19 (42%) were deposited by coyotes; of 41 scats that would have been field-identified as deposited by coyotes based on diameter <30 mm criterion, 20 (49%) were deposited by Mexican wolves. Halfpenny's (1986) suggested diameter criterion for field identification of scats identified 3 of the scats as gray (Urocyon cinereoargenteus) or red fox (Vulpes vulpes; 0% correct), 24 as coyote (62% correct), and 20 as Mexican wolf (75% correct). Discriminant analysis indicated that diameter and mass of scats offered the best results for accurately classifying coyote scats (86%) but provided relatively low accuracy for classifying Mexican wolf scats (65%). Our results suggest that previous diet studies using traditional identification methods may have misrepresented the diets of both the North American gray wolf and the coyote when the 2 species were sympatric. Molecular scatology appears to be a more definitive scat-identification technique than traditional field methods or odor for these canids.

Commercially available telemetry collars for wildlife that employ Global Positioning System (GPS) devices generally have the ability to gather a large volume of precise location data. We appraised the performance of 12-channel Televilt GPS-Simplex™ collars (Televilt/TVP Positioning AB, Lindesberg, Sweden) deployed across western and northern Canada on grizzly bears (Ursus arctos). Of 71 collar deployments between 2000 and 2002, 38 were retrieved and performed according to their programmed schedule, 20 were retrieved and had some degree of failure, and 13 experienced catastrophic failures and were not retrieved. In addition to these deployments, 10 collars failed predeployment. GPS collar fix success rates were greater for the retrieved collars from the Northwest Territories than for the 4 study areas in British Columbia and Alberta (F_4,50 = 10.82, P < 0.001); thus, the latter areas were grouped for further analyses. Collar fix success rates in the British Columbia and Alberta study areas differed between the retrieved collars that functioned normally (x̄ = 65%, SE = 2.3, n = 28) and collars retrieved with failure events (x̄ = 56%, SE = 4.3, n = 17; t₄₃ = 2.09, P = 0.043). Fix success rates were lower the longer collars were in the field (r_s = −0.35, n = 45, P = 0.020). Locations from the GPS collars had a mean dilution of precision of <4 for 2D and 3D locations and thus had a good degree of precision. We were satisfied with the volume and quality of the location data; however, we advise other researchers that significant time and money may be lost troubleshooting problems with the Televilt Simplex system. Other recommendations for future and current users are considered.

We carried out a study on age determination for Spanish red deer (Cervus elaphus hispanicus) from growth marks in dental cementum. We investigated the age at which the first growth layer and first rest line appear in cementum of incisors (I₁), molars (M₁), and canines (C), and explained how to interpret these marks to determine age. We evaluated accuracy and precision of aging with rest lines of different tooth types. Age was estimated using a standardized counting method and a linear regression analysis, both based on rest-line number in permanent teeth of red deer aged between 4 and 44 months. The first growth layer occurred after dental eruption in all teeth studied. The first rest line appeared at 6 months in molars (M₁) and at 15 months in incisors (I₁). The second rest line appeared at 18 months in molars and incisors. Each consecutive rest line represented one year more in animal age. Subsequent analysis showed that canines do not give an accurate estimation of the real age. Molars and incisors did not yield the same values for age estimation. Molars gave the best results, aging 75% of animals correctly, while only 49% were aged correctly using incisors. Nevertheless, within a one-year confidence interval, 99% of the animals were aged correctly using molars, versus 86% using incisors. We suggest using the first lower molar for deer aging in Sierra Morena. Use of regression should be preferred to the standardized counting method for age determination when using incisors.

The ability to non-invasively monitor stress hormone levels in free-ranging animals could significantly aid in conservation and management efforts. Our objective in this study was to demonstrate the effectiveness of assay of fecal corticoid metabolites in detecting a stress response in cougars (Puma concolor). Fecal samples were collected from 9 captive cougars before and after an artificial stressor. Steroid hormones were extracted from the samples. Adrenal corticoid metabolite concentrations of the resulting extracts were quantified using cortisol and corticosterone assays. Results indicated that fecal glucocorticoid metabolite levels increased significantly 24 hours after the stressor in 6 of the 9 individuals. Behavior correlated with the hormonal response; all cougars that displayed a flight response to the stressor also had elevated stress hormone measures. Elevated levels of stress hormones were not observed in individuals that did not attempt to flee. We have demonstrated with this study that measurement of fecal hormone metabolites is sufficiently sensitive to detect an adrenal response to stress in cougars and could be applied in the field to monitor stress levels in free-ranging populations.

Preventing birds from perching on the sensor units of the Federal Aviation Administration's Low Level Wind-shear Alert System (LLWAS) is crucial to its successful operation. In this study we evaluated, under controlled conditions, responses of brown-headed cowbirds (Molothrus ater), fish crows (Corvus ossifragus), great horned owls (Bubo virginianus), barred owls (Strix varia), and black vultures (Coragyps atratus) to several anti-perching devices. No device was totally successful against every species. Of the 5 original test devices, the most effective perching deterrent was a set of 17 stout spikes (“AgSpikes”) secured to the central portion of the sensor unit that point up 0° to 30° from the vertical. The central spikes were subsequently redesigned and combined with 9 metal bushings (3 for each arm of the sensor unit) that fit loosely on the sensor arms and that were armed with 5 sharp spikes each. This “AgSpikes and SpikedSpinner” combination unit was as effective as the original AgSpikes for all birds except owls, which were able to place their feet within the open spaces of the redesigned AgSpike portion of the device and perch on the 3 horizontal spikes. The combination units should adequately discourage most large and small birds from perching on LLWAS sensors. The availability of alternate perches in the field will likely enhance the effectiveness of the deterrent. Monitoring performance of the combination units deployed in the field is recommended to verify that they are working as expected.

Survival and cause-specific mortality of white-tailed deer (Odocoileus virginianus) have been well documented in forested habitat, but limited information has been collected in intensively farmed regions. The objectives of this study were to determine survival and cause-specific mortality of neonate, fawn female, and adult female white-tailed deer in an intensively farmed (>80% land cover) region of Minnesota. We captured and radiocollared 77 female deer >8 months old (61 adults, 16 fawns) and 39 neonates (17 male, 22 female). Hunting was the greatest cause of mortality among adult deer, with 43% of mortalities attributed to firearms hunters. Annual survival rate of all adult and fawn (≥8 months) radiocollared deer was 0.77 (n = 58, SE = 0.06). Overall (Jan. 2001-Aug. 2002) adult survival was 0.75 (n = 77, SE = 0.05) and was similar to survival rates reported elsewhere for female white-tailed deer. Natural causes (e.g., disease, predation) of mortality were minor compared to human-related causes (e.g., hunting, vehicle collision). In total, 67% of neonate mortalities were due to predators. Neonate summer survival rate pooled over years was 0.84 (n = 39, SE = 0.06) and was high compared to other studies. High neonate survival was likely associated with a low predator density, quality vegetation structure at neonate bed sites, and high nutritional condition of dams. Deer management in the highly fragmented and intensively farmed regions of Minnesota relies on hunter harvest to maintain deer populations at levels tolerable to landowners.

Rehabilitating and releasing abandoned or “picked up” white-tailed deer (Odocoileus virginianus) fawns back to the wild is a popular alternative to euthanasia, but the fates of these fawns are often unknown. We measured survival rates and sources of mortality for radiomarked white-tailed deer fawns that were orphaned or picked up by the public, raised by wildlife rehabilitators, and released into the wild. A total of 14 of 23 and 8 of 19 fawns during 2000 and 2001, respectively, died within 30 days of release. The Kaplan-Meier 100-day survival rate was 0.232 for all deer. We found no difference in survival distributions based on rehabilitation site. Sources of mortality for released fawns were canids (50%), unknown cause (20%), accidents (10%), bobcats (Lynx rufus) (10%), poaching (6%), and legal harvest (3%). Most rehabilitated and released fawns died, but those that survived did so around human dwellings and may have become a nuisance or presented public safety concerns.

Nutritional habitat quality in unmanaged southeastern forests often is limited because a dense midstory and litter layer impede growth of high-quality, shade-intolerant forage species. Management actions often are designed to improve the quantity of natural forages and to supplement natural forages with agronomic plantings. We evaluated the use of a selective herbicide, prescribed fire, and fertilizer to improve forage production for white-tailed deer (Odocoileus virginianus) in naturally regenerated, mature loblolly pine (Pinus taeda) stands in north-central Mississippi, treated during 1998–1999. We compared nutritional quality and production of selected forages in treated plots (n = 4) and untreated plots (n = 4) during years 2 and 3 post-treatment. We also measured quality and production of cowpeas (Vigna unguiculata) produced in food plots (n = 4). Treatment plots produced an average of 435 kg/ha of leaf biomass and 34 kg/ha of digestible protein; untreated plots averaged 119 ka/ha of leaf biomass and 7 kg/ha of digestible protein. Cowpea food plots produced 545 kg/ha of leaf biomass and 110 kg/ha of digestible protein. Carrying-capacity estimates (deer-days/ha) increased from 7 in untreated plots to 268 in treated plots. Extrapolated over a 10-year economic planning horizon, the cost of producing digestible protein was $8/kg for treated plots and $15/kg for cowpea food plots. Vegetation treatments as described can cost-effectively produce high-quality, natural deer forages.

A program to control wolves (Canis lupus) in interior Alaska in 1993 and 1994 did not result in expected increases in calf survival in the Delta caribou (Rangifer tarandus) herd (DCH). Therefore, the Alaska Department of Fish and Game conducted a study to determine causes of calf mortality during 1995–1997 and monitored recruitment, mortality, and population size annually in the DCH for 6 years after wolf control ended. Despite removal of 60–62% of the autumn 1993 wolf population, wolves still killed 25% of 166 radiocollared calves between birth in mid- to late May and 30 September during 1995–1997. Although autumn calf:cow ratios in the DCH increased after wolf control, similar increases in calf:cow ratios occurred in the adjacent Denali Herd, where wolves were not controlled. Calf:cow ratios following wolf control in 1993 and 1994 were lower than ratios obtained in the same area after wolf control from 1976–1982. We identified 4 factors that contributed to continued low calf:cow ratios in the DCH following the 1993–1994 wolf control program: 1) other predators in combination (i.e., golden eagles [Aquila chrysaetos] and grizzly bears [Ursus arctos]) were the most significant mortality source for caribou calves, 2) the temporal and spatial extent for wolf removal was inadequate to effectively reduce wolf predation, 3) in 1987 the DCH shifted its main calving area, a move that may have increased predation by golden eagles and grizzly bears, and 4) natality rates and nutritional condition of caribou declined during the 5 years before wolf control coincident with a density-dependent population decline. We conclude that wolf control within the range of the DCH failed because the wolf trapping program did not remove enough wolves and was not conducted long enough to substantially reduce predation by wolves on caribou calves. In addition, wolves that lived outside the control area were responsible for about 40% of the wolf-caused mortality to collared caribou calves, and significant numbers of calves died from unknown, neonatal causes.

Previous research in the Milne Point oilfield in northern Alaska showed that the density of caribou (Rangifer tarandus) in the calving period within 1 km of a road was significantly lower after construction than before construction of the road. This was interpreted as displacement from the road and a functional loss of habitat and has been extensively cited as a documented effect of oilfield development on caribou. We continued this study with additional aerial surveys flown during 1991–2001 and compared caribou numbers and density in 6 1-km intervals from the road over 3 time periods: pre-road construction (1978–1981), early post-road construction (1982–1987), and recent post-road construction (1991–2001). During the recent post-road period, the densities of calves and of all caribou were not significantly lower within 1 km of the road than the densities in the pre-road period. In addition, calf density was higher in the interval within 1 km of the road than in the intervals 1–6 km from the road during the recent post-road construction period. The total number of calving caribou observed in the study area has declined since pre-road construction and early post-road periods, but we found no evidence that caribou using the area during calving avoided areas near the road during the recent post-road period. Numbers of caribou in the study area during the post-calving period (after 20 June) during 1991–2001 were highly variable, but generally were higher than during calving. Analyses of relationships between calving and post-calving caribou densities and distance intervals from Milne Point Road suggested that distributions of calves and adult caribou were not strongly influenced by presence of the road.

Nest predation impacts duck production and recruitment in many areas of North America. Yet little research has been conducted to evaluate beliefs of waterfowl managers about predation of duck nests or predation management strategies. We surveyed 176 waterfowl managers employed by the United States Fish and Wildlife Service (USFWS) and state wildlife agencies to determine their beliefs about the impact of nest predation on duck populations and evaluate their use and perceptions of different predation management techniques. The overall survey response rate was 85% for USFWS and 92% for state managers. Managers believed predation was having a significant impact on duck-nest success. Over 64% of respondents reported that rates of nest success on their management units averaged <30% between 1996–2000. Concomitantly, most managers (93%) reported implementing >1 technique on their management area to reduce nest predation, but most techniques were rated as only somewhat effective. Habitat management (e.g., establishment of dense nesting cover), nesting structures, and lethal control (e.g., trapping) of predators were perceived as being the most effective methods to reduce nest predation. To successfully manage nest predation in the future, managers believed more information is needed about the impact of control techniques on nontarget species and some technical aspects of technique implementation.

We evaluated the use of goose-dropping density as an index of food-consumption volume using white-fronted geese (Anser albifrons) foraging on spilled grains in rice fields. It was revealed that even when the dropping densities were similar at 2 sites, the actual rice-consumption volume varied greatly with initial grain density in the field. Also, it was shown that regardless of dropping density, rice-consumption volume was less variable among fields with low initial grain density. Some possible reasons for the weak relationship between dropping density and rice consumption were discussed. Based on our results, we suggest that wildfowl's dropping density is likely to have a limited capability as an indicator of food-consumption volume, and we propose some directions for improving its effectiveness.

Food availability influences population demographics and harvest of wildlife species throughout the Appalachians. Various combinations of hard- and soft-mast indices were compared to white-tailed deer (Odocoileus virginianus), eastern wild turkey (Meleagris gallopavo), and black bear (Ursus americanus) statewide harvests in West Virginia, USA, 1980–2002. Hard-mast conditions had a negative relationship with total white-tailed deer (r = −0.5774, P = 0.004), archery white-tailed deer (r = −0.5979, P = 0.003), antlerless whitetailed deer (r = −0.5065, P = 0.014), wild turkey (r = −0.6193, P = 0.002), and black bear archery (r = −0.6065, P = 0.002) harvests. Hard-mast conditions had a positive relationship with black bear gun harvests (r = 0.6975, P ≤ 0.001). Negative nonsignificant (P > 0.05) relationships were measured between mast conditions and buck white-tailed deer and muzzleloader white-tailed deer harvests. Hard mast black cherry (Prunus serotina) had the strongest negative relationship with wild turkey (r = −0.6497, P ≤ 0.001) harvest, whereas oak (Quercus spp.) had the greatest negative relationship with total white-tailed deer (r = −0.6238, P = 0.002), archery white-tailed deer (r = −0.6133, P = 0.002), and antlerless whitetailed deer (r = −0.5648, P = 0.005) harvests. Total hard mast had the greatest positive relationship with black bear gun (r = 0.6975, P ≤ 0.001) and greatest negative relationship with black bear archery (r = −0.6065, P = 0.002) harvests. Soft-mast conditions did not relate to harvest of any big-game species (P > 0.05). Our results supply wildlife biologists with data that may be used in setting seasons or predicting harvests for the public.

Wildlife biologists use current land-cover databases to understand wildlife—habitat relationships but must make assumptions about potential vegetation and successional dynamics when predicting species responses to ecological changes. Understanding the potential of habitat types to provide wildlife habitat components throughout succession, as opposed to solely examining current suitability with land cover, has important implications for white-tailed deer (Odocoileus virginianus) management as challenges such as overabundance and diseases emerge. Our objectives were to develop a process to identify and delineate habitat-type boundaries, determine successional pathways, develop landscape-scale models to quantify deer habitat potential, and describe how habitat-potential models could be used in planning. We delineated habitat-type boundaries and identified successional pathways using digital vegetation and geologic databases and information from the literature for an 8,100-km² area in northeastern Lower Michigan. We identified deer habitat requirements from the literature; constructed models to quantify fall and winter food, thermal cover, and spring and summer habitat suitability throughout succession; and projected suitability throughout the study area spatially and temporally. Regional differences in habitat types (e.g., poorly drained coniferous types in the northern portion and dry—mesic deciduous or mixed coniferous—deciduous types in the southern portion of the study area) determined regional differences in habitat potential. Generally in the study area, fall and winter food suitability was highest during early (<30 years)- and mid-successional stages (30–100 years), thermal-cover suitability was highest in middle stages, and spring and summer habitat suitability was highest in early stages. The process presented can help managers define wildlife management goals through an understanding of landscape composition, the spatial arrangement and successional changes of habitat types, and their relationship to populations.

North American grasslands continue to decline in quantity and quality. In the northern mixed-grass prairie, potential edge and fragmentation effects on grassland birds are poorly understood and conclusions are based largely on data from outside the region. Lands in and adjacent to J. Clark Salyer National Wildlife Refuge in north-central North Dakota comprise one of the largest contiguous patches of northern mixed-grass prairie remaining in North America. However, within the region, aspen (Populus tremuloides), willow (Salix spp.), and other woody species have increased, such that continued existence of grasslands is threatened. We examined how breeding grassland birds responded to habitat that has been variably fragmented by encroaching woody vegetation. The probability of occurrence decreased markedly for 11 of 15 bird species (including 3 endemic to the northern Great Plains) as percent woodland, tall shrub, or brush cover increased. Bird species were increasingly affected as the height of woody plants increased from brush to tall shrubs to trees. Grasslands became largely unsuitable for 9 species as woodland cover exceeded 25%. Derived models can be used by land managers to predict the outcome of management actions that alter plant community succession or that restore grasslands degraded by woody invasion.

Habitat management for an endangered species may affect nontarget communities. We examined avian community response to pine—grassland restoration for red-cockaded woodpeckers (Picoides borealis) and traditional United States Forest Service pine sawtimber management at Homochitto National Forest, Mississippi from 1994–1996. Thirteen species were more abundant in pine-grassland restoration stands, whereas 5 species were more abundant in traditionally managed pine sawtimber stands. Mature restored pine-grassland stands had greater avian species richness, total bird abundance, and avian conservation value than traditionally managed pine sawtimber stands. We used logistic regression models in an exploratory analysis to predict occurrence of selected species using stand- and landscape-scale habitat characteristics. Probability of redeyed vireo (Vireo olivaceus) occurrence increased with increasing hardwood canopy cover, and probability of yellow-breasted chat (Icteria virens) occurrence increased with increasing grass ground cover. Species richness, total avian abundance, and occurrence of red-eyed vireos and Bachman's sparrows (Aimophila aestivalis) increased with increasing values of Shannon's Habitat Diversity Index. Pine-grassland restoration for red-cockaded woodpeckers created vegetation composition and structure at the stand and landscape scales that may benefit numerous avian species of regional conservation concern.

There are many reasons to want to know the true surface area of the landscape, especially in landscape analysis and studies of wildlife habitat. Surface area provides a better estimate of the land area available to an animal than planimetric area, and the ratio of this surface area to planimetric area provides a useful measure of topographic roughness of the landscape. This paper describes a straightforward method of calculating surface-area grids directly from digital elevation models (DEMs), by generating 8 3-dimensional triangles connecting each cell centerpoint with the centerpoints of the 8 surrounding cells, then calculating and summing the area of the portions of each triangle that lay within the cell boundary. This method tended to be slightly less accurate than using Triangulated Irregular Networks (TINs) to generate surface-area statistics, especially when trying to analyze areas enclosed by vector-based polygons (i.e., management units or study areas) when there were few cells within the polygon. Accuracy and precision increased rapidly with increasing cell counts, however, and the calculated surface-area value was consistently close to the TIN-based area value at cell counts above 250. Raster-based analyses offer several advantages that are difficult or impossible to achieve with TINs, including neighborhood analysis, faster processing speed, and more consistent output. Useful derivative products such as surface-ratio grids are simple to calculate from surface-area grids. Finally, raster-formatted digital elevation data are widely and often freely available, whereas TINs must generally be generated by the user.

The concept of carrying capacity originally was developed for domestic grazers and does not make provision for the wide variety of diets found in wild African herbivores. In the African savannas, herbivores are classified into 4 basic dietary classes: low-selective grazers, high-selective grazers, mixed feeders, and browsers. Given these conditions, a more appropriate approach was needed than the agricultural method based on livestock units to determine stocking rates for wildlife. Consequently, a new approach was developed that recognizes plant resource variation at the plant community level and differentiates between the grazing and browsing component in the diet of herbivores in the African savannas. The model used to calculate the grazing and browsing capacity on wildlife ranches provides for rainfall variability, quality and quantity of available grazing and browse, dietary requirements of each type of wildlife, and availability of suitable habitat. In this model the conventional conversion of wildlife to a Large Stock Unit has been replaced by a Grazer Unit, which is the equivalent of a 180-kg blue wildebeest (Connochaetes taurinus), and a Browser Unit, which is the equivalent of a 140-kg greater kudu (Tragelaphus strepsiceros). By separating the grazing and browsing components in the diet of wildlife for stocking density calculation, the diversity in the vegetation resources is optimally utilized. This concept is exemplified with an actual case study of a wildlife ranch in a South African savanna. In doing so, quantitative and clearly defined parameters are provided on which to base wildlife management decisions.

Currently, there are no accepted standards in the wildlife literature for reporting details of digital map products used to assess habitat. Digital maps developed from remotely sensed images vary widely in how they represent landscapes. Consequently, certain characteristics of remotely sensed data need to be addressed when reporting results obtained from digital maps to allow the reader to understand the strengths and limitations of the map product(s) used. We reviewed 44 articles published in The Journal of Wildlife Management between 2000–2002 that used digital maps developed from aerial photography or satellite imagery to assess wildlife habitat and summarized which map parameters were reported and which were overlooked. We found that most papers failed to report important details about digital map products used to assess wildlife habitat. To provide an example of variability in digital map products, we compared digital maps developed from aerial photographs and satellite imagery that we used to measure vegetation characteristics within northern spotted owl (Strix occidentalis caurina) territories as part of a region-wide demographic study. We found that the 2 map types produced quite different measurements of vegetation for the same area. Many differences that we observed are inherent to aerial photo and satellite maps in general. We provide a suggested list of map details to be reported when using digital vegetation maps to quantify wildlife habitat.

Northern bobwhites (Colinus virginianus) are one of the most broadly researched and intensively managed species in North America. However, we argue that a disadvantage of this status is that traditional management principles currently are incompatible with the spatial scale necessary to address the nationwide decline in bobwhite abundance. We maintain that halting or reversing this decline will entail 2 principal changes in the scale of management. Primarily we suggest that habitat oversight must switch from historical fine-scale management (promotion of edge habitat, weedy fencelines, disked strips, living hedges, and food plots) to regional management of usable space. Secondly, within these regional management areas, we should apply harvest management that employs risk-sensitive strategies that conservatively avoid undermining the primary goal. This entails narrowing the scale of harvest management from statewide to regional levels. If these ideological changes cannot be made and historical policies remain in force, we risk failing to stabilize, let alone increase, bobwhite populations.

Blackbird (family lcteridae) depredation on sunflower (Helianthus annuus) crops in the prairie states of the United States has motivated the proposed use of an avicide, DRC-1339 (3-chloro-4-methylaniline), to decrease their numbers. The resulting mortality of blackbirds at wetland roosts could increase the potential of avian botulism occurring in affected marshes. To assess this possibility, we seeded (artificially placed) blackbird carcasses in selected wetlands in Stutsman County, North Dakota, during August-September 2000 and July-September 2001 to evaluate their rate of decomposition and role in initiating avian botulism outbreaks. We monitored carcasses to determine their persistence, the frequency and amount of maggots produced, and the presence of type C botulinum toxin. In 10 of our 12 study wetlands, blackbird carcasses were not rapidly removed by scavengers, thus providing substrate for maggot growth and potential production of Clostridium botulinum toxin. Decomposition of carcasses occurred rapidly, and maggot production averaged 4–5 g per carcass within 9 days. We were unable to detect C. botulinum type C toxin in any of the 377 blackbird carcasses or the 112 samples of maggots we collected in 2000 or 2001. None of the 25 blackbird carcasses we tested contained botulinum spores, the most probable explanation for the absence of botulinum toxin production. Our results indicate that the likelihood of DRC-1339-poisoned blackbirds causing botulism outbreaks would be minimal in North Dakota wetlands during late summer and early autumn.

There are growing concerns among conservationists that commercial trade in many species of wild-caught turtles may not be sustainable. Little information on the turtle trade and its impact on populations is available at the national level, and there are no analyses of the commercial trade in turtles in Texas. To quantitatively describe the turtle trade in Texas, we surveyed government organizations, pet and meat establishments, reptile expositions, zoos, aquariums, and Texas herpetological societies by mail, phone calls, or visits. We used the United States Fish and Wildlife Service’s (USFWS) Law Enforcement Management Information System (LEMIS) database to quantify the turtle trade in Texas from 1995-2000. Five turtle species accounted for 99% of collections from the wild in 1999, but at least 69 native and exotic species were available in the pet and meat markets. Nonnative species were exported from Texas, implying that they were either imported from other states and re-exported from Texas or were bred in captivity. Unfortunately, the current national wildlife trade monitoring system does not distinguish between export and re-export, making it difficult to fully understand wildlife trade patterns. Turtle populations in general were susceptible to overexploitation. We recommend that populations of commercially exploited turtles be monitored to build databases required for establishing harvest quotas and size limits. Methods used in this study could be implemented by other states to monitor their turtle trade.

With a set of external measurements from a sample of known-sex American crows (Corvus brachyrhynchos) in central Illinois, we determined whether a published discriminant function for sex determination was applicable to crows in a different geographic location than the reference sample. Low classification success with this equation, likely due to geographic size differences in crows between regions, led to the creation of new age-specific discriminant functions, which correctly classified the sex of 100%, 100%, and 89% of hatch-year, subadult, and adult crows, respectively. This technique for gender determination is of timely importance as the American crow is a sentinel for West Nile virus transmission, and ecological studies of this species are important in understanding transmission dynamics. Gender determination by discriminant function of these Midwestern crows indicated that the 2002 West Nile virus epizootic did not cause sexbiased mortality.

We assessed the effect of radiotelemetry on the growth, reproduction, and survival of black ratsnakes (Elaphe obsoleta) using data from a 6-year study. Transmitters were surgically implanted for more than one year and were <2.5% of the snakes' mass and 3.8% of their length. Compared to snakes without transmitters, snakes with transmitters exhibited lower annual growth in mass but not length, and females produced lighter clutches of eggs relative to their body size. Although results were equivocal, radiotelemetry also may have adversely affected survival. Potential explanations for the negative effects of radiotelemetry include direct effects of transmitters on snakes (impaired behavior, cost of transportation, infection) and indirect effects (increased disturbance by researchers). Because we conducted the study at the northern limit of the species' distribution, snakes in this population may be particularly sensitive to the negative effects of radiotelemetry. Despite the apparent costs, we believe that use of radiotelemetry is still warranted because of the benefits realized.

We evaluated the effects of temporary, prominently displayed signs in reducing deer-vehicle collisions (DVCs) during mule deer (Odocoileus hemionus) migrations. To conduct the study we selected segments of 5 highways in 3 western states that were crossed by mule deer during seasonal migrations. Using local input and historical DVC data, we identified migration corridors used by deer. We separated these migration corridors into sections of equal length. Each section was separated by a buffer zone. We randomly assigned each section into treatment or control areas. In treatment areas we erected temporary warning signs equipped with reflective flags and solar-powered flashing amber lights. To evaluate the effectiveness of signs in reducing DVCs, we monitored deer mortalities during migration periods before and after signs were placed. We also monitored vehicle speeds to determine whether the signs affected motorist behavior. DVCs in the treatment areas were reduced by 50%. Vehicle speeds also were reduced, but evidence suggested that the effect eroded during the second year of the study. Study results indicated that temporary signing can be a cost-effective technique when used on roads where DVC peaks occur in conjunction with seasonal migration periods and are isolated to narrow corridors.

Conflict resolution between stakeholder groups and management agencies is a problem in wildlife management. We evaluated our success in resolving a conflict between sportsmen and the Colorado Division of Wildlife (CDOW). Sportsmen challenged the credibility of methods used to estimate numbers of mule deer (Odocoileus hemionus) in Colorado and demanded validating surveys to verify numbers of deer. Sportsmen, other interested wildlife stakeholders, and CDOW engaged in a conflict resolution process and designed and implemented an aerial survey to estimate numbers of deer in a specific population whose previous estimated size had been contested by sportsmen. We used helicopters to count mule deer on randomly selected sample units distributed on deer winter range in March 2001. Estimated population size was 6,782 ± 2,497 (90% CL) using stratified random sample estimators and 11,052 ± 3,503 (90% CL) when counts of deer were adjusted using the Idaho mule deer sightability model. Both aerial survey estimates supported computer-modeled population estimates of 7,000–7,300 deer that had been contested by sportsmen, and all estimates were greater than the sportsmen’s estimate of 1,750 deer, determined from their casual observations. After the survey, sportsmen did not accept survey estimates despite their involvement in the design, analysis, and interpretation of the validation survey. By failing to support results of a validation survey they had demanded, the credibility of sportsmen plummeted among other stakeholders, the Colorado Wildlife Commission, and outside public entities while credibility of CDOW managers rose. We contend that CDOW successfully met the challenges of sportsmen because the aerial-survey systems used to validate deer numbers were founded on credible science and applied within a resolution process that elicited trust from most stakeholders. We caution other agencies facing similar challenges to use tested methods that can withstand public scrutiny, allow ample time for planning and implementing, carefully assess technical and political risks associated with potential outcomes, and engage multiple stakeholders in planning efforts to gain the trust of participants. Cost of this resolution process was about $100,000 US.

Little is known about the effects of wildfire on black bears (Ursus americanus). Following a wildfire in Arizona, we hypothesized that the local black bear population would decline due to direct mortality or reductions in food and cover. We also hypothesized that remaining bears would have larger home ranges than bears in unburned areas because of decreased food resources and cover. To test our hypotheses, we studied short-term effects of a wildfire on black bear demographics in the Mazatzal Mountains, central Arizona, from 1997–2000 and compared these parameters to those in an unburned area. We also compared density estimates, survival, cub production and survival, and home-range sizes in the same area prefire (1973–1978) to postfire (1997–2000). We captured 31 adult bears within the burn perimeter on Four Peaks and 15 on unburned Mt. Ord during 1997–2000. Adult sex ratio within the burn perimeter on Four Peaks was more skewed toward males (4 M:1 F) than in the unburned area on Mt. Ord (1.7 M:1 F), or the same area prefire (1.4 M: 1 F). Subadults comprised 20% of captured bears in both study areas. The largest apparent impact of the wildfire was lack of recruitment of cubs to the yearling age class. Five adult females produced 16 cubs within the burn perimeter on Four Peaks during 1997-1999, but none survived to 1 year of age. Four females in the unburned area produced 13 cubs, and 36% survived to 1 year of age; in a prefire study, 48% of cubs survived to 1 year on Four Peaks. Hunting was the greatest cause of adult mortality in both areas. Estimated black bear superpopulation size within the burn ranged from 27–36; a simultaneous density estimate of the 120-km² area was 13.3/100 km². Because the majority of activity occurred in the 26.2 km² of unburned area within the burn perimeter, the density could have been as high as 73.8 bears/100 km². Superpopulation size in the 120-km² unburned study area ranged from 21–30; density was estimated at 12.5 bears/100 km². Female home-range sizes were similar between pre and postburn and unburned Mt. Ord. Managers should be aware of possible negative short-term consequences of wildfire on black bear populations and manage to increase cub survival.

Few reliable methods exist for estimating population size of large terrestrial carnivores. This is particularly true in forested areas where sightability is low and when radiocollared individuals are unavailable in the target population. We used stratified network sampling to sample wolf (Canis lycaon) tracks in the snow to estimate density in western Algonquin Park, Ontario in February 2002. We partitioned our 3,425-km² study area into 137 5 × 5-km sample units (SU) and stratified SUs as having a high (n = 61) or low (n = 76) probability of containing detectable wolf tracks based on the relative amount of watercourses and conifer cover within each block. We used a Bell 206B helicopter to survey 28 high (46%) and 17 low (22%) SUs. When fresh tracks were found in a block, we followed the tracks forward to the wolves themselves and then backward until the tracks were no longer considered “fresh.“ We observed 17 “fresh“ track networks within 45 SUs. The average pack size in the area we surveyed was 4.2 ± 0.4 (SE). These observations resulted in an estimate of 87 ± 11.4 (90% CI) wolves in the study area, for a density of 2.5 ± 0.3 wolves/100 km². We detected no violations of the assumptions of this survey design and obtained a similar density estimate (2.3 wolves/100 km²) in 2003 using location data from 24 radiocollared wolves in 10 packs from an area that overlapped our 2002 survey area. The sampling unit probability estimator (SUPE) provides an objective, accurate, and repeatable means of estimating wolf density with an associated measure of precision. However, tracking wolves in forested cover was time-consuming, so costs will be considerably higher per unit area in forested areas relative to the more open cover types where this technique was originally developed.

The ocelot (Leopardus pardalis) is an endangered cat native to south Texas. Urbanization and agricultural development have resulted in limited and fragmented habitat, making ocelot habitat restoration an important factor in the cat's recovery. We evaluated the use of United States Department of Agriculture-Natural Resource Conservation Service (USDA-NRCS) soil surveys to identify potential restoration sites by examining ocelot habitat use in south Texas from 1982–1990. We analyzed an 8-year data set of ocelot radiotelemetry locations using Geographic Information Systems (GIS) and Bailey's confidence intervals. Ocelots selected habitat with dense (>95%) canopy cover more than open (<75%) canopy cover. Ocelots also selected Camargo, Lardeo, Olmito, and Point Isabel soil series in greater proportion than available. The selected soils also represented 82% of the selected dense canopy cover areas. Our results suggest that USDA-NRCS soil survey maps can be used as a tool for identifying potential areas for ocelot habitat restoration.

The raccoon (Procyon lotor) has greatly expanded its range in the Canadian prairies during the 1900s. Four non-exclusive explanations may explain this range expansion: introductions, mesopredator release, availability and suitability of winter denning sites, and food availability. No introductions of raccoons were documented for the prairies, suggesting that range expansion was not directly caused by humans. The suggestion that raccoons moved north because of “mesopredator release” appears implausible because, even where larger predators such as bobcats (Lynx rufus) and coyotes (Canis latrans) exist, raccoons experience low predation rates and also because raccoons have expanded their range into treeless areas where coyotes are abundant. The third hypothesis, suggesting that availability of winter denning sites limits raccoon distribution, also receives little support, mostly because of the raccoon's flexibility in using a variety of natural and anthropogenic structures for denning. The last hypothesis, the idea that raccoon range expansion has followed an increase in availability of food, appears most plausible. The effects of global warming, which affects not only the availability and diversity of foods but also the duration of the growing season (and thus temporal availability of food), probably helped raccoons colonize new areas.

Digital land-cover data are among the most popular data sources used in ecological research and natural resource management. However, processes for accurate land-cover classification over large regions are still evolving. We identified inconsistencies in the National Land Cover Dataset 1992, the most current and available representation of land cover for the conterminous United States. We also report means to address these inconsistencies in a bird-habitat model. We used a Geographic Information System (GIS) to position a regular grid (or lattice) over the upper midwestern United States and summarized the proportion of individual land covers in each cell within the lattice. These proportions were then mapped back onto the lattice, and the resultant lattice was compared to satellite paths, state borders, and regional map classification units. We observed mapping inconsistencies at the borders between mapping regions, states, and Thematic Mapper (TM) mapping paths in the upper midwestern United States, particularly related to grassland-herbaceous, emergent-herbaceous wetland, and small-grain land covers. We attributed these discrepancies to differences in image dates between mapping regions, suboptimal image dates for distinguishing certain land-cover types, lack of suitable ancillary data for improving discrimination for rare land covers, and possibly differences among image interpreters. To overcome these inconsistencies for the purpose of modeling regional populations of birds, we combined grassland-herbaceous and pasture-hay land-cover classes and excluded the use of emergent-herbaceous and small-grain land covers. We recommend that users of digital land-cover data conduct similar assessments for other regions before using these data for habitat evaluation. Further, caution is advised in using these data in the analysis of regional land-cover change because it is not likely that future digital land-cover maps will repeat the same problems, thus resulting in biased estimates of change.

The discovery of bovine tuberculosis (caused by Mycobacterium bovis) in white-tailed deer (Odocoileus virginianus) and other free-ranging Michigan wildlife has made ongoing surveillance for the disease a reality for wildlife professionals. The wide susceptibility of mammals, including humans, to M. bovis led us to be concerned with the potential risks of acquiring tuberculosis that Michigan Department of Natural Resources staff face in their occupational activities. Consequently, we developed a bovine tuberculosis occupational safety program for our staff and volunteer cooperators taking part in disease surveillance. Close similarities between bovine and human tuberculosis allowed occupational safety principles used in human health care to be used as a guide. We produced an occupational safety training document to educate personnel about bovine tuberculosis in humans, evaluate the risk posed by job duties, and make recommendations on risk mitigation. Following implementation, the National Institute for Occupational Safety and Health conducted field evaluations of the occupational safety program that validated its protectiveness for workers. As wildlife disease surveillance becomes a greater responsibility for management agencies across the United States, we believe the lessons learned in development of the Michigan program can be widely adapted to other areas and potentially to other diseases, and can raise awareness of occupational exposure to zoonotic diseases.

West Nile virus (WNV) resulted in a 25% decline in survival in four populations of radiomarked greater sage-grouse (Centrocercus urophasianus) across Alberta, Wyoming, and Montana in 2003. Unexpected impacts of WNV are disturbing because range-wide habitat loss and degradation already threaten sage-grouse populations. In the Powder River Basin of Wyoming and Montana, late-summer survival of sage-grouse was lower at a site with confirmed WNV mortalities (20%) than at two sites without (76%). Dramatic declines in both male and female lek attendance at the WNV site the following spring suggest that outbreaks may threaten some local populations with extirpation. The key to understanding broader impacts of WNV on sage-grouse is to monitor additional populations and to determine whether populations infected in 2003 are again impacted this year. To facilitate this process, we describe a strategy for monitoring WNV mortality in the field and provide information on how to handle, store, and submit dead birds for testing.