The distribution of grizzly (Ursus arctos) and American black bears (U. americanus) overlaps in western North America. Few studies have detailed activity patterns where the species are sympatric and no studies contrasted patterns where populations are both sympatric and allopatric. We contrasted activity patterns for sympatric black and grizzly bears and for black bears allopatric to grizzly bears, how human influences altered patterns, and rates of grizzly–black bear predation. Activity patterns differed between black bear populations, with those sympatric to grizzly bears more day-active. Activity patterns of black bears allopatric with grizzly bears were similar to those of female grizzly bears; both were crepuscular and day-active. Male grizzly bears were crepuscular and night-active. Both species were more night-active and less day-active when ≤1 km from roads or developments. In our sympatric study area, 2 of 4 black bear mortalities were due to grizzly bear predation. Our results suggested patterns of activity that allowed for intra- and inter-species avoidance. National park management often results in convergence of locally high human densities in quality bear habitat. Our data provide additional understanding into how bears alter their activity patterns in response to other bears and humans and should help park managers minimize undesirable bear–human encounters when considering needs for temporal and spatial management of humans and human developments in bear habitats.

Understanding den selection for the federally threatened Louisiana black bear (Ursus americanus luteolus) will assist managers in effectively managing bear populations and the landscapes they inhabit. We assessed den selection of 72 female Louisiana black bears at multiple spatial scales in northern and central Louisiana, USA. We used 230 den-years to examine den type preference, microhabitat characteristics of dens, and effects of landscape characteristics on den selection. We also evaluated reuse of tree dens and their availability across several study areas. Bears selected tree dens more frequently (65%) than ground dens. Most (55%) ground dens were associated with standing or downed trees, and most tree dens were in baldcypress (Taxodium distichum; 86%) or surrounded by water (80%). Selection of ground dens was positively associated with landscape metrics related to presence of water, whereas selection of tree dens was positively associated with proximity to edge and greater proportions of swamp and areas containing water. Reuse of tree dens averaged 15% (range  =  0–20%) across study areas and our estimates of tree-den availability indicated that tree dens were not a limiting resource for Louisiana black bears in the northern or central portions of Louisiana. Although Louisiana black bears demonstrated plasticity in den selection, we recommend managers use forest management practices that conserve appropriate tree dens and create ground-denning opportunities, because both would promote the recovery of Louisiana black bear populations.

We investigated seasonal patterns in resource selection of Canada lynx (Lynx canadensis) in the northern Rockies (western MT, USA) from 1998 to 2002 based on backtracking in winter (577 km; 10 M, 7 F) and radiotelemetry (630 locations; 16 M, 11 F) in summer. During winter, lynx preferentially foraged in mature, multilayer forests with Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) in the overstory and midstory. Forests used during winter were composed of larger diameter trees with higher horizontal cover, more abundant snowshoe hares (Lepus americanus), and deeper snow compared to random availability; multilayer, spruce–fir forests provided high horizontal cover with tree branching that touched the snow surface. During winter, lynx killed prey at sites with higher horizontal cover than that along foraging paths. Lynx were insensitive to snow depth or penetrability in determining where they killed prey. During summer, lynx broadened their resource use to select younger forests with high horizontal cover, abundant total shrubs, abundant small-diameter trees, and dense saplings, especially spruce–fir saplings. Based on multivariate logistic-regression models, resource selection occurred primarily at a fine spatial scale as was consistent with a sight-hunting predator in dense forests. However, univariate comparisons of patch-level metrics indicated that lynx selected homogenous spruce–fir patches, and avoided recent clear-cuts or other open patches. Given that lynx in Montana exhibit seasonal differences in resource selection, we encourage managers to maintain habitat mosaics. Because winter habitat may be most limiting for lynx, these mosaics should include abundant multistory, mature spruce–fir forests with high horizontal cover that are spatially well-distributed.

Optimal management of invasive pests can benefit from quantitative measures of rates of recruitment, and particularly, relative contributions of immigration and reproduction. However, these vital rates are difficult to estimate by trapping or observation. Recent studies have demonstrated that analyses with DNA markers may provide detailed information on the origin of immigrants into pest populations, but these studies have not provided comparable data on reproductive rates. We integrated genetic and demographic information from a unique longitudinal data set to comprehensively quantify recruitment during the past 15 years into an island population of red foxes (Vulpes vulpes) and to reveal relative contributions of immigration and reproduction. This population established 100 years ago and persists despite several decades of management aimed at population suppression. Primary source of recruits on the island was in situ reproduction (>95%/annum), although the number of foxes reproducing was small relative to the total number present. Immigration occurred at rates up to 3.6%/annum and was primarily by dispersing males, but is unlikely to be demographically important. We also show that although fox control effectively reduced fox density, there was evidence that control did not reduce the net number of recruits, most likely because the population exhibited a density-dependent release from reproductive suppression. Our results imply that fox control on Phillip Island should primarily focus on reducing on-island abundance and reproduction, but eradication will not be sustained unless immigration ceases.

Dynamics of herbivore populations can be influenced both by density-dependent processes and climate. We used age-at-harvest data for adult female white-tailed deer (Odocoileus virginianus) collected over 23 years to estimate survival and reproduction by age class and to identify effects of environmental factors. The study population was located on Anticosti Island (QC, Canada), at the northern limit of the species' range; the population was at high density, and the landscape had scarce forage and abundant snow during winter. Despite severe environmental conditions, population growth apparently increased during the study; adult survival was similar to other populations, although reproduction appeared lower. Winter severity was not related to survival, but density affected adult female survival. Density at estrus was the main factor influencing reproduction of 2- and 3–4-year-olds and also affected reproduction of prime-aged females (5–9-yr-olds), but not of older females. Reproductive rate of younger females was influenced by environmental conditions in autumn, such as high density or snow conditions that limited forage availability. Reproductive success of 5–9- and ≥10-year-old females appeared dependent on spring conditions favoring high-quality forage, probably through effects on neonatal survival. Relative to other studies on northern ungulates, demographic processes in our study appeared to be more affected by autumn and spring climate, in addition to population density, than by winter climate. We thus propose that population density, as well as autumn and spring climate, should be considered in management strategies. Harvest data offered a unique opportunity to study forest ungulates, for which individual monitoring is rarely possible.

Postpartum behavior of maternal deer may be specific to species of deer and predators. We captured sympatric white-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus eremicus) fawns from radiocollared adult females in 2004–2006 on rangelands of west central Texas, USA, where predators larger than bobcats (Lynx rufus) were absent. Our objective was to determine whether differences in postpartum antipredator behavior existed between deer species, and if so, examine efficacy of those strategies. We collected postpartum group cohesion data in 2004 and 2005 by using radiotelemetry and examined dead fawns for cause of mortality. During fawns' hider phase, <3 weeks postpartum, mule deer females kept fawns closer to themselves (95% CI  =  39–66 m) and twins closer to each other (95% CI  =  25–49 m) than did white-tailed deer females (95% CIs  =  152–234 m and 163–255 m, respectively). After 30 days postpartum, familial group cohesion was similarly tight for both species. During hider phases from 2004 to 2006, predated carcasses of white-tailed deer fawns (11 of 11) were dismembered or consumed more than mule deer fawns (7 of 13, P  =  0.016), which was one line of evidence for maternal defense by mule deer adults. During hider phases in 2004 and 2005, predation rate of mule deer fawns was lower than that for white-tailed deer fawns. In 2006, predation rate increased for mule deer but was similar for white-tailed deer fawns compared with previous years. The tight cohesion strategy of mule deer exhibited in 2004 and 2005 seemed successful at thwarting small predators. Without large predators, the loose cohesion strategy of white-tailed deer females was maladaptive. When meso-predators are abundant due to extermination of larger predators, predation on fawns could increase if a deer species has relatively fixed postpartum maternal antipredator behavior.

Effective management of wildlife populations often requires motivating hunters to harvest sufficient numbers of animals of prescribed sex and age classes to meet management goals. For cervids, it is convenient to design harvest regulations relative to presence (male) or absence (young and female) of antlers because harvest of females has a larger effect on population growth. We used regression techniques to evaluate effects of 2 supplemental hunting programs based on additional days of hunting opportunity and an additional incentive used to complement additional days on harvest of antlered and antlerless deer in Wisconsin, USA. Earn-a-buck regulations, an incentive-based program that requires hunters to register an antlerless deer before being authorized to harvest an antlered deer, were associated with an average increase of 2.04 deer/km² in antlerless harvest and a 0.60 deer/km² decrease in harvest of antlered deer. Providing more opportunity for hunting of antlerless deer in the form of 4- and 8-day supplemental firearm seasons was associated with 1.10 deer/km² and 1.32 deer/km² increases, respectively, in antlerless harvest with trivial (0.02 deer/km² and 0.09 deer/km²) decreases in harvests of antlered deer. Our analysis suggests that extra days of hunting opportunity coupled with the earn-a-buck incentive was 56–88% more effective at increasing antlerless harvest relative to additional days of hunting without the incentive. Use of the earn-a-buck incentive resulted in decreased harvest of antlered deer and was disliked by many hunters. Quantifying these relationships is important for helping managers predict the costs and benefits of various hunting programs.

Supplementary feeding is a widespread game management practice in several red deer (Cervus elaphus) populations, with important potential consequences on the biology of this species. In Mediterranean ecosystems food supplementation occurs in the rutting period, when it may change mating system characteristics. We studied the role of food supplementation relative to natural resources in the spatial distribution, aggregation, and mean harem size of females in Iberian red deer (Cervus elaphus hispanicus) during the rut. We studied 30 red deer populations of southwestern Spain, 63% of which experienced supplementary feeding. Using multivariate spatial analyses we found that food supplementation affected distribution of females in 95% of the populations in which it occurred. Green meadows present during the mating season acted as an important natural resource influencing female distribution. Additionally, the level of female aggregation and mean harem size were significantly higher in those populations in which food supplementation determined female distribution than in populations in which female distribution did not depend on supplementary feeding. Because female aggregation and mean harem size are key elements in sexual selection, supplementary feeding may constitute an important anthropogenic element with potential evolutionary implications for populations of Iberian red deer.

Indirect interactions among species can strongly influence population dynamics and community structure but are often overlooked in management of large mammals. We estimated survival of Dall's sheep (Ovis dalli) in the central Alaska Range, USA, during years of differing snowshoe hare (Lepus americanus) abundance to test whether indirect interactions with a cyclic hare population affect Dall's sheep either negatively, by subsidizing predators (apparent competition), or positively, by diverting predation (apparent commensalism). Annual survival of adult female sheep was consistently high (0.85 for all yr and age classes combined). In contrast, annual estimates of lamb survival ranged from 0.15 to 0.63. The main predators of lambs were coyotes (Canis latrans) and golden eagles (Aquila chrysaetos), which rely on hares as their primary food and prey on lambs secondarily. Coyotes and eagles killed 78% of 65 radiocollared lambs for which cause of death was known. Lamb survival was negatively related to hare abundance during the previous year, and lamb survival rates more than doubled when hare abundance declined, supporting the hypothesis of predator-mediated apparent competition between hares and sheep. However, stage-specific predation and delays in predator responses to changes in hare numbers led to a positive relationship between abundance of adult Dall's sheep and hares. Lacking reliable estimates of survival, a manager might erroneously conclude that hares benefit sheep. Thus, support for different indirect effects can be obtained from different types of data, which demonstrates the need to determine the mechanisms that create indirect interactions. Long-term survey data suggest that predation by coyotes is limiting this sheep population below levels typical when coyotes were rare or absent. Understanding the nature of indirect interactions is necessary to effectively manage complex predator–prey communities.

Transportation planners are increasingly incorporating roadway design features to mitigate impacts of highways on wildlife and to increase driver safety. We used camera and track surveys to evaluate wildlife use before and after construction of 3 wildlife underpasses and associated fencing on a new section of United States Highway 64 in Washington County, North Carolina, USA. We recorded 242 occasions of white-tailed deer (Odocoileus virginianus) use of underpass areas before highway construction began. Following completion of the highway, we collected 2,433 photographs of 9 species with deer representing 93% of all crossings. Adjusting for differences in number of monitoring days, white-tailed deer use of underpass areas averaged 6.7 times greater after the new highway and underpasses were completed. We recorded 3,614 wildlife crossings of ≥20 species based on track counts, representing most medium and large mammals known to occur in the area and several reptiles and birds. After completion of the highway, we documented wildlife mortality due to vehicle collisions during a 13-month period and recorded 128 incidences representing ≥24 species. Within fenced highway segments, mortalities were lowest near underpasses and increased with distance from the underpasses. However, we also documented more mortalities in fenced areas compared with unfenced areas. With greater distance from an underpass, animals with smaller home ranges seemed less likely to reach the underpass and instead attempted to climb over or crawl under fencing. Based on collision reports from adjacent highway sections, the new section of United States Highway 64 experienced approximately 58% fewer wildlife mortalities (primarily white-tailed deer), suggesting underpasses and fencing reduced the number of deer–vehicle collisions. Continuous fencing between underpasses may further reduce the number of vehicle collisions for deer but additional design features (e.g., buried fencing) should be considered for other wildlife species.

In 1954 and 1955, I conducted studies on 4 beaver (Castor canadensis) colonies in Routt County, Colorado, USA, to develop a reliable and practical census method. In fall of 1955, these colonies were trapped to extirpation to obtain accurate counts and colony compositions. I established photo stations and took a series of photographs approximately every 5 years, in late September, from 1955 to 2005 to document beaver-population dynamics and beaver-pond successional changes after complete beaver removal. The number and configuration of dams, ponds, and canals remained remarkably similar, with maintenance conducted by succeeding generations of beaver. Quaking aspen (Populus tremuloides) and autumn willow (Salix serissima) boundaries also remained stable, but conifers slowly encroached. At 3 of 4 colony sites, beaver did not attempt to construct food caches for overwintering. By fall of 2005, the fourth site was also without a cache. Carrying capacity of these areas was likely limited by severe winter weather at 2,620-m to 2,900-m elevations, aspen depletion, pond-depth reduction, and sustained grazing by cattle. Although beaver carefully maintained dams, pond depths were reduced in most cases. This slow transition from an aquatic to a terrestrial system is a natural progression in this region.

Research into the use of predator-odor–based repellents as a management tool has gained momentum during the past 30 years. Some studies have suggested that odors from a predator whose diet includes the target species are more effective than odors from a predator that does not consume the species. To evaluate this management tool in the Australian context and to determine the effect, if any, of predator diet on odor repellence, we tested eutherian and metatherian, predator fecal odors on phylogenetically separated pest species that currently occur in Australia. We evaluated fecal odors from tigers (Panthera tigris) and Tasmanian devils (Sarcophilus harrisii) as repellents for goats (Capra hircus) and eastern grey kangaroos (Macropus giganteus). We fed tigers and Tasmanian devils 2 diets: one of goat and one of eastern grey kangaroo. The test fecal odors were more effective than a control odor of carrier material and solvent at deterring goats (P < 0.001) and kangaroos (P  =  0.02) from food. Tiger fecal odor was more effective than Tasmanian devil odor in deterring both goats (P  =  0.001) and kangaroos (P  =  0.03). We observed a decrease in the number of feeding events for goats when they were exposed to the odor from a tiger fed goat compared with all other predator–diet combinations (P < 0.001). We also observed a decrease in feeding events for kangaroos when exposed to the odor from a tiger fed kangaroo compared with all other predator–diet combinations. We observed signs of desensitization to the test odors in goats and habituation to the test odors in kangaroos over the experimental period. A better understanding of the factors involved in desensitization and habituation may increase the effectiveness of fecal odor–based repellents as a humane and nonlethal management tool for managers.

Snowshoe hares (Lepus americanus) are an important prey species for Canada lynx (Lynx canadensis) and are considered critical for lynx population persistence. Determination of snowshoe hare distribution and abundance is needed by land management agencies for lynx conservation. An accepted approach for estimating snowshoe hare abundance is the use of fecal-pellet plot counts. Locally derived regression equations are preferred for accurate calibration of pellet counts to snowshoe hare density due to local differences in pellet deposition and decomposition. We used linear regression to examine correlations between snowshoe hare density, as determined by mark–recapture estimates, and pellet plot counts on both uncleared plots and annually cleared plots on the Bridger-Teton National Forest, western Wyoming, USA. We found significant correlations between snowshoe hare density estimates and fecal pellet counts for both uncleared and annually cleared pellet counts; however, the relationship was stronger (higher r) when using pellet counts from annually cleared plots. In addition, we found that adjusting the buffer size by omitting hard habitat edges (not used by hares) around trapping grids improved correlations between snowshoe hare density and fecal pellet counts for both uncleared plots and annually cleared plots. Though precision is sacrificed when using uncleared plots, they may be useful as a coarse index of habitat use by snowshoe hares. Our derived regression equations may be useful to identify important foraging habitat for Canada lynx in western Wyoming. Land managers responsible for conserving snowshoe hare habitat in western Wyoming may use these equations to monitor changes in hare populations among habitats and during prescribed management actions.

Recently, a conservation strategy developed to restore populations of black-tailed prairie dog (Cynomys ludovicianus) suggested reintroducing animals into the Chihuahuan Desert grasslands of the southwestern United States. Rainfall in desert habitats is lower and more variable compared to rainfall near the center of the prairie dog's range. Additionally, peak rainfall comes months after prairie dogs reproduce in these desert systems. Thus, southwestern populations may be less prolific and fluctuate more than those found in northerly climes. Using mark–recapture and mark–resight techniques, we estimated reproduction and monthly survival from 577 individuals inhabiting 6 reintroduced colonies from 2003 to 2005 in the northern Chihuahuan Desert. During 2003 precipitation was 64% of the long-term average, whereas both 2004 and 2005 had near-average precipitation. Probability that a female became pregnant, number of juvenile prairie dogs emerging from maternity burrows, and date of emergence were all correlated to adult female body mass. Adult monthly survival decreased from >0.95 during spring to 0.70 in summer 2003, following a rapid loss in adult body mass that coincided with low precipitation. In 2003 monthly juvenile survival was near zero on 2 of the 3 largest colonies and growth rates of juveniles were half that of subsequent years. Estimated population size declined by 68% (range  =  18–91%) from 2003 to 2004, and 5 of 6 populations declined an average of 75% from their original introduction size. Prairie dog populations in desert environs may have a high risk of extirpation caused by weather patterns indicative of desert climates. Our results are important for those managers involved in the conservation of prairie dogs and we suggest that regional differences should be carefully considered prior to any reintroduction effort.

River otters (Lontra canadensis) select specific habitat features when establishing latrines, but no studies have described latrine features in arid and semiarid environments. We developed a model describing those habitat features that influence otter latrine site selection on rivers in arid and semiarid watersheds of western Colorado, USA. River otters selected latrine sites with the presence of beaver (Castor canadensis) activity, large prominent rocks, adjacent to deeper water, with shading over the site, and rock or cliff overstory. Our model provides a robust predictive tool for identifying river otter latrine sites in arid environments of southwestern North America.

The northern goshawk (Accipiter gentilis) has been the subject of considerable interest because of the impact of logging on this species' nesting habitat. However, few studies have examined movements of fledgling birds around the nest prior to independence, and even fewer have described resource requirements of young birds during their postfledging period. Over 3 years, we followed 31 radiotagged goshawk fledglings from 15 nests in southeastern British Columbia, Canada. Of these birds, 26 survived to disperse. Between fledging and dispersal 95% of fledgling relocations (n  =  1,148) were within 450 m of the nest. Fledglings primarily remained within 298 m of the nest during the first 21 days postfledging and within 525 m of the nest between 21 days postfledging and dispersal. Fledglings' movements were highly directional, with individual and sibling movements away from any particular nest tending out in one direction. Postfledging areas averaged 36.7 ha in size (median  =  23.1, inter-quartile range  =  20.8–39.7 ha). Fledglings strongly avoided forest <40 years old and weakly selected young forests (40–80 yr), mature forests (>80 yr), and stands with >40% canopy cover during the first 21 days and after. We suggest forest managers wishing to conserve goshawk postfledging areas in the interior montane forests of British Columbia maintain forests >40 years old with high crown closure covering an area ≥21 ha and preferably >40 ha. This area should contain all identified occupied and alternative nest trees in a nest area. At least half this area should be forest >80 years old and contain existing nests and potential for future nest trees.

Off-road vehicle (ORV) traffic is one of several forms of disturbance thought to affect shorebirds at migration stopover sites. Attempts to measure disturbance effects on shorebird habitat use and behavior at stopover sites are difficult because ORV disturbance is frequently confounded with habitat and environmental factors. We used a before-after-control-impact experimental design to isolate effects of vehicle disturbance from shorebird responses to environmental and habitat factors. We manipulated disturbance levels within beach closures along South Core Banks, North Carolina, USA, and measured changes in shorebird abundance and location, as well as the activity of one focal species, the sanderling (Calidris alba), within paired control and impact plots. We applied a discrete treatment level of one flee-response-inducing event every 10 minutes on impact plots. We found that disturbance reduced total shorebird and black-bellied plover (Pluvialis squatarola) abundance and reduced relative use of microhabitat zones above the swash zone (wet sand and dry sand) by sanderlings, black-bellied plovers, willets (Tringa semipalmata), and total shorebirds. Sanderlings and total shorebirds increased use of the swash zone in response to vehicle disturbance. Disturbance reduced use of study plots by sanderlings for resting and increased sanderling activity, but we did not detect an effect of vehicle disturbance on sanderling foraging activity. We provide the first estimates of how a discrete level of disturbance affects shorebird distributions among ocean beach microhabitats. Our findings provide a standard to which managers can compare frequency and intensity of disturbance events at other shorebird stopover and roosting sites and indicate that limiting disturbance will contribute to use of a site by migratory shorebirds.

Geographically isolated breeding populations of migratory shorebirds may be demographically connected through shared nonbreeding habitats. We used long-term (1998–2008) mark–recapture data on piping plovers (Charadrius melodus) collected from 7 separate studies located throughout North America to conduct a range-wide analysis of after hatch year apparent survival (Φ_AHY). Our objectives were to compare concurrent survival estimates from disparate breeding sites and determine whether estimates followed similar trends or were correlated among breeding populations with shared wintering grounds. Average survival estimates were higher for Great Plains populations (range  =  0.69–0.81) than for Great Lakes and Atlantic Coast populations (range  =  0.56–0.71). Linear trend models indicated that apparent survival declined in 4 out of 7 populations, was unchanged in 3, and was generally highest among Great Plains populations. Based on a post hoc analysis, we found evidence of correlated year-to-year fluctuations in annual survival among populations wintering primarily along the southeastern United States Atlantic Coast and Gulf Coast. Our results indicate shared overwintering or stopover sites may influence annual variation in survival among geographically disparate breeding populations. Declines in piping plover survival are a cause for concern, and our results highlight the need for conservation efforts to include habitat used during the migratory and wintering periods.

An accurate understanding of factors influencing survival and how they affect population growth are required to determine the best conservation strategies for small populations, especially near the limit of a species' range. We estimated adult and juvenile survival for a small population of the threatened western snowy plover (Charadrius alexandrinus nivosus) in coastal northern California over 7 years (2001–2007). We also evaluated population structure and growth to determine the relative importance of immigration and local recruitment. Apparent survival for adult males (φ  =  0.61 ± 0.08) was greater than that of adult females (φ  =  0.50 ± 0.11), and survival of adults was greater than for juveniles (φ  =  0.40 ± 0.06). An algebraic assessment of population growth (λ) revealed that fecundity and survival were insufficient to maintain the population (λ  =  0.66–0.77), whereas estimates based on consecutive annual counts (λ  =  0.96 ± 0.26) and a Pradel model (λ  =  0.92 ± 0.11) suggested the population was more stable. These results, combined with annual variation in the number of newly marked plovers, indicate that the local population was maintained by immigration and can be classified as a sink. Management actions aimed at increasing fecundity, including predator control and greater restrictions on human activity, may be necessary to maintain this population; actions aimed at increasing adult survival are more challenging.

The parasitic nematode Trichostrongylus tenuis has a detrimental effect on red grouse (Lagopus lagopus scoticus) at the individual and population levels. Treatment using grit coated with the anthelmintic fenbendazole hydrochloride reduces parasite infection and increases grouse density. However, a frequent and low dose of anthelmintic increases selection pressure for parasite resistance, a serious practical and economic problem. We used an egg hatch assay to test resistance of T. tenuis from 12 moors in northern England, which differed in grit treatment intensity. The anthelmintic concentration that prevented 50% and 95% of T. tenuis eggs from hatching (ED₅₀ and ED₉₅, respectively) did not differ among moors and were not related to treatment. We suggest annual monitoring and responsible anthelmintic use to prevent resistance so that medicated grit continues to enhance red grouse management.

Greater sage-grouse (Centrocercus urophasianus) are dependent on sagebrush (Artemisia spp.) for food and shelter during winter, yet few studies have assessed winter habitat selection, particularly at scales applicable to conservation planning. Small changes to availability of winter habitats have caused drastic reductions in some sage-grouse populations. We modeled winter habitat selection by sage-grouse in Alberta, Canada, by using a resource selection function. Our purpose was to 1) generate a robust winter habitat-selection model for Alberta sage-grouse; 2) spatially depict habitat suitability in a Geographic Information System to identify areas with a high probability of selection and thus, conservation importance; and 3) assess the relative influence of human development, including oil and gas wells, in landscape models of winter habitat selection. Terrain and vegetation characteristics, sagebrush cover, anthropogenic landscape features, and energy development were important in top Akaike's Information Criterion–selected models. During winter, sage-grouse selected dense sagebrush cover and homogenous less rugged areas, and avoided energy development and 2-track truck trails. Sage-grouse avoidance of energy development highlights the need for comprehensive management strategies that maintain suitable habitats across all seasons.

Spatial and temporal closures of anthropogenic activities are a common management strategy to increase waterfowl usage of an area. However, empirical evidence, specifically how individual waterfowl respond to disturbance, is lacking to support their efficacy. We exposed radiomarked mallards (Anas platyrhynchos) to walk-in, shooting, or no disturbance along the South Platte River corridor in Colorado, USA, from September to February during 2006–2007 and 2007–2008. Mallards exposed to shooting disturbance had greater mean flight distance after disturbance (FDAD) during September–November (4.58 km, 95% CI  =  3.55–5.62) than December–February (3.04 km, 95% CI  =  2.51–3.58) and were 35% and 17% greater than mean FDAD of mallards exposed to walk-in disturbance, respectively. Walk-in and shooting disturbance had a similar effect on return rates, and disturbed mallards had higher (0.09–0.41) movement probabilities away from and lower (0.15–0.20) probabilities of returning to treatment locations than controls. Probability of presence of disturbed mallards was 37% lower than controls during the daytime but was equal at night. Mallards exposed to walk-in (0.38 [95% CI  =  0.30–0.46]) and shooting (0.23 [95% CI  =  0.17–0.30] disturbance had low return rates the first afternoon after a disturbance compared to controls (0.71 [95% CI  =  0.65–0.77]). A high proportion of mallards exposed to walk-in (0.75 [95% CI  =  0.67–0.83]) and shooting (0.70 [95% CI  =  0.64–0.76]) disturbance returned to treatment locations in ≤1 day. Managers may be able to more effectively manage disturbance regimes by 1) accounting for surrounding lands within <10 km, especially lands within <5 km, 2) being conscientious when establishing regulations that will affect levels of disturbance 1–2 days after a previous disturbance, and 3) considering shooting and walking disturbance equally for refuge design.

Grassland birds endemic to the central shortgrass prairie ecoregion of the United States have experienced steep and widespread declines over the last 3 decades, and factors influencing reproductive success have been implicated. Nest predation is the major cause of nest failure in passerines, and nesting success for some shortgrass prairie birds is exceptionally low. The 3 primary land uses in the central shortgrass prairie ecoregion are native shortgrass prairie rangeland (62%), irrigated and nonirrigated cropland (29%), and Conservation Reserve Program (CRP, 8%). Because shortgrass–cropland edges and CRP may alter the community of small mammal predators of grassland bird nests, I sampled multiple sites on and near the Pawnee National Grasslands in northeast Colorado, USA, to evaluate 1) whether small mammal species richness and densities were greater in CRP fields and shortgrass prairie–cropland edges compared to shortgrass prairie habitats, and 2) whether daily survival probabilities of ground-nesting grassland bird nests were negatively correlated with densities of small mammals. Small mammal species richness and densities, estimated using trapping webs, were generally greater along edges and on CRP sites compared to shortgrass sites. Vegetation did not differ among edges and shortgrass sites but did differ among CRP and shortgrass sites. Daily survival probabilities of artificial nests at edge and CRP sites and natural nests at edge sites did not differ from shortgrass sites, and for natural nests small mammal densities did not affect nest survival. However, estimated daily survival probability of artificial nests was inversely proportional to thirteen-lined ground squirrel (Spermophilus tridecemlineatus) densities. In conclusion, these data suggest that although land-use patterns on the shortgrass prairie area in my study have substantial effects on the small mammal community, insufficient data existed to determine whether land-use patterns or small mammal density were affecting grassland bird nest survival. These findings will be useful to managers for predicting the effects of land-use changes in the shortgrass prairie on small mammal communities and avian nest success.

The combination of ecological site descriptions and state-and-transition models (STMs) describes potential vegetation, plant composition, and plant community dynamics and thus can be used to classify and understand dynamics of wildlife habitats across landscapes or home ranges. Numerous studies have evaluated effects of plant community dynamics on diversity and abundance of wildlife populations, but we could find no studies that examined changes in wildlife populations with respect to STMs. We compared abundance of grasshopper sparrows (Ammodramus savannarum) across 5 community phases representing 2 different ecological states in the Columbia Basin, Oregon, USA, to evaluate utility of STMs for understanding and predicting potential changes in habitat use by wildlife species. We measured grasshopper sparrow abundance in 165 100-m fixed-radius point counts distributed across 17 study plots within 5 plant community phases: native perennial grassland, sagebrush-steppe, depleted sagebrush-steppe, sagebrush-steppe with an annual grass understory, and annual grassland. We used a general estimating equation with a Poisson distribution to model relative abundance and estimate differences in this abundance index between linked pairs of community phases. Grasshopper sparrows showed clear differences in abundance among community phases and were most numerous in perennial grasslands and least abundant in depleted sagebrush and sagebrush annual grass community phases. As a management tool, STM provides information that predicts the direct and indirect cumulative impacts of various management actions on vegetation composition and structure (and thus habitat). Ecological site descriptions and STMs enable land managers and scientists to assess potential and current wildlife habitat suitability and to predict potential response of wildlife populations to vegetation dynamics based on the ecological potential of the site.

Prescribed fire is used widely to manage grasslands on National Wildlife Refuges and other public lands in the northern Great Plains, but its effects on habitat use or production of wildlife in the region are poorly understood. During 1998–2003, we used point counts to examine effects of prescribed fire on vegetation and passerines in a mixed-grass prairie complex in north-central North Dakota, USA (n  =  7 units, each 40–70 ha). Vegetation structure and, to a lesser extent, plant community composition varied with year of study (likely related to changes in annual precipitation) and with number of growing seasons since fire. Fire altered plant structure, especially the amount of residual vegetation, which in turn influenced bird species richness and abundance. The number of indicated pairs for sedge wren (Cistothorus platensis), clay-colored sparrow (Spizella pallida), Le Conte's sparrow (Ammodramus leconteii), Savannah sparrow (Passerculus sandwichensis), and bobolink (Dolichonyx oryzivorus) were lowest during the first postfire growing season but generally increased and stabilized within 2–3 postfire growing seasons. Our results support the premise that grassland passerines are well-adapted to frequent, periodic fires, generally corresponding to those occurring prior to Euro–American settlement of the region. Prescribed fire is important for reducing tree and shrub invasion, restoring biological integrity of plant communities, and maintaining or enhancing populations of grassland-dependent bird species. Managers in the northern mixed-grass prairie region should not be overly concerned about reductions in bird abundances that are limited mostly to the first growing season after fire.

Bird electrocution on power lines is an important conservation problem that affects many endangered species. We surveyed 3,869 pylons in the Barcelona Pre-littoral Mountains (Catalonia, NE Spain) and collected 141 carcasses of electrocuted birds, mainly raptors and corvids. Univariate analysis indicated that metal pylons with pin-type insulators or exposed jumpers, with connector wires, located on ridges, overhanging other landscape elements, and in open habitats with low vegetation cover were the most dangerous. A logistic regression model indicated that the probability of a pylon electrocuting a bird was mainly related to pylon conductivity, distribution of the conductive elements on the cross-arms, cross-arm configuration, habitat, topography, whether the pylon was overhanging other landscape elements, and presence of rabbits (Oryctolagus cuniculus). We validated the predictive power of this model by using a random sample of 20% of all pylons surveyed. We found that bird mortality was aggregated mainly on pylons assigned a high probability risk by the model. Pylons included in the very high electrocution risk category (9.2%) accounted for 53.2% of carcasses, whereas pylons classified in the low electrocution risk category (54.5%) only accounted for 3.5% of mortality. Power companies employed this classification to prioritize the correction of 222 pylons by installing alternate cross-arms and suspended jumpers and isolating wires and jumpers. We evaluated the effectiveness of this mitigation strategy. A significant fall in the mortality rate on corrected pylons combined with the lack of any reduction in the mortality rate in a sample of 350 noncorrected pylons indicated that the model selected adequately the most dangerous pylons and that the applied correction measures were effective. Consequently, our strategy may be a useful tool for optimizing efforts and resources invested in solving the problem of bird electrocution.

Anthraquinone (AQ)-based repellents have been shown to reduce Canada goose (Branta canadensis) use of turfgrass; however, impacts of frequent mowing on efficacy of AQ have not been studied. Our objective was to determine efficacy and longevity of a rain-fast AQ-based avian repellent, FlightControl® PLUS (FCP), as a deterrent of free-ranging resident Canada geese under 2 mowing frequencies. We conducted the study at 8 sites in the Triangle region (Raleigh, Durham, and Chapel Hill) of North Carolina, USA. We arranged our experiment in a randomized complete block design, with each of 8 sites containing 4 0.1-ha treatment combinations: 1) treated with FCP and mowed every 4 days (T4), 2) treated with FCP and mowed every 8 days (T8), 3) untreated and mowed every 4 days, and 4) untreated and mowed every 8 days. We conducted 4 37-day field sessions (Jun–Jul 2007, Sep–Oct 2007, Jun–Jul 2008, and Sep–Oct 2008), representing the summer molting phase and the full-plumage phase. Resident goose use (measured by daily no. of droppings) was 41–70% lower on treated plots than on untreated plots, but use was similar between T4 and T8. Average FCP coverage on grass blades decreased in coverage from approximately 95% to 10% over the 30-day posttreatment phase. Results indicate that resident Canada goose use of FCP-treated turfgrass areas was lower than untreated areas even when chemical coverage on grass was 10%. Further, mowing frequency did not have a clear impact on the efficacy of FCP as a Canada goose repellent.

Severe population declines were reported for common eiders (Somateria mollissima) in western Greenland over the period 1960–2000. A monitoring program, concurrent with more restrictive hunting regulations on common eiders, revealed breeding numbers increasing by 212%, from 2,558 active nests in 2000 to 7,982 nests in 2007. Though it was not possible to directly link harvest reduction and population growth in West Greenland, a similar increase in breeding numbers in Canada was correlated with the harvest reduction in Greenland and linked to increasing adult survival and recruitment of first-time breeders, and a similar explanation is suggested for West Greenland. The study emphasizes that appropriate restrictions in hunting can be efficient in wildlife management and that common eiders can sustain dramatic rates of increase during population regrowth. It also shows that cost-efficient monitoring programs can be established through cooperation with local residents.

Tree cavities likely vary in their thermal quality for cavity-nesting animals, which could be especially important during winter. We conducted a winter field experiment to test whether cavities vary either in their buffering capacity or in their mean temperature according to predictable characteristics. We found that cavities buffered temperature and that there was a lag effect in temperature that appeared to be related to heating and cooling. Diameter at breast height was the most important variable influencing cavity temperature during the day, with smaller trees warming up more. During the night, diameter at breast height and tree decay class were important, such that larger, live trees cooled down less. Maintaining live trees with cavities in managed forests should be considered in addition to snag retention, because live trees appear to provide warmer structures during winter.

Occupancy models that account for imperfect detection are often used to monitor anuran and songbird species occurrence. However, presence–absence data arising from auditory detections may be more prone to observation error (e.g., false-positive detections) than are sampling approaches utilizing physical captures or sightings of individuals. We conducted realistic, replicated field experiments using a remote broadcasting system to simulate simple anuran call surveys and to investigate potential factors affecting observation error in these studies. Distance, time, ambient noise, and observer abilities were the most important factors explaining false-negative detections. Distance and observer ability were the best overall predictors of false-positive errors, but ambient noise and competing species also affected error rates for some species. False-positive errors made up 5% of all positive detections, with individual observers exhibiting false-positive rates between 0.5% and 14%. Previous research suggests false-positive errors of these magnitudes would induce substantial positive biases in standard estimators of species occurrence, and we recommend practices to mitigate for false positives when developing occupancy monitoring protocols that rely on auditory detections. These recommendations include additional observer training, limiting the number of target species, and establishing distance and ambient noise thresholds during surveys.

We determined wolverine (Gulo gulo) distribution and occurrence probabilities using aerial surveys and hierarchical spatial modeling in a 180,000-km² portion of Interior Alaska, USA. During 8 February–12 March 2006, we surveyed 149 of 180 1,000-km² sample units for wolverine tracks. We observed wolverine tracks in 99 (66.4%) sample units. Wolverine detection probability was ≥69% throughout the survey period. Posterior occurrence probabilities of whether a wolverine track occurred in a sample unit was dependent on survey timing, number of transects flown, number of neighboring sample units with detected tracks, percentage of the sample unit with elevation ≤305 m, and human influences. Our model indicated strong evidence of occurrence (>0.80) in 72% of the 180 survey units, strong evidence of absence (<0.20) in 12%, and weak evidence of occurrence or absence (0.20–0.80) in 16%. Wolverine area of occupancy made up 83% of the study area. Simulations illustrated that 2–4 survey routes were necessary for the survey technique to provide strong evidence of wolverine presence or absence in Interior Alaska if a track was not identified along the first route. The necessary number of survey routes depends on the occurrence probability in a sample unit. We provided managers with a map of wolverine distribution in Interior Alaska and an efficient and lower-cost method to detect coarse-scale changes in wolverine distribution. Our technique was effective in both Interior Alaska and Ontario, Canada, suggesting it would be effective throughout most of the boreal forest range of wolverines where tracks can be readily observed from the air. The technique requires a certain skill level in recognizing tracks; it is essential that tracks are identified correctly and training may be necessary depending on surveyor experience.

Noninvasive genetic monitoring of animal populations has become a widely used method in animal conservation and wildlife management due to its known advantages in sample availability of endangered or elusive species. A variety of methods have been suggested to overcome the difficulties of collecting reliable genetic data despite poor DNA quality and quantity of samples. We used quantitative real-time polymerase chain reaction (qPCR) to quantify DNA contents and preselect extracts suitable for microsatellite genotyping of noninvasive samples from 2 carnivore species, wolf (Canis lupus) and Eurasian otter (Lutra lutra). We tested 2 concentration thresholds for DNA extracts containing either 5 pg/µL or 25 pg/µL at minimum and evaluated the effect of excluding samples from genotyping falling below either of these DNA concentrations. Depending on species and threshold concentration applied, we reduced the genotyping effort by 21% to 47% and genotyping errors by 7% to 45%, yet we could still detect 82% to 99% of available genotypes. Thus, qPCR may potentially reduce genotyping effort and enhance data reliability in noninvasive genetic studies. Genetic laboratories working on noninvasive population genetic studies could transfer this approach to other species, streamline genetic analyses and, thus, more efficiently provide wildlife managers with reliable genetic data of wild populations.

Recent miniaturization and weight reductions of Global Positioning System (GPS) collars have opened up deployment opportunities on a new array of terrestrial animal species, but the performance of lightweight (<90 g) GPS collars has not been evaluated. I examined the success of 42 GPS collars from 3 manufacturers (Televilt/TVP Positioning, AB, Lindesburg, Sweden; Sirtrack Ltd., Havelock North, New Zealand; H.A.B.I.T [HABIT] Research Ltd., Victoria, BC, Canada) in stationary, open-sky conditions and during deployments on brushtail possums (Trichosurus vulpecula), a nocturnal arboreal marsupial. I assessed performance of these collars in terms of technical malfunctions, fix-success rates, battery longevity, and aspects of location quality. Technical malfunctions occurred in >50% of HABIT and Televilt collars, whereas all Sirtrack collars operated normally. Fix-success rates for all brands were significantly higher during stationary tests than when deployed on brushtail possums. HABIT and Televilt brands functioned poorly in field conditions, with success rates of 16.2% and 2.1%, respectively. Sirtrack collars had the highest fix rate when deployed (64.8%). I modified several HABIT collars by changing the GPS antenna location, with a resultant substantial increase in field fix success (92.6%). Most collars ceased working before they reached 50% of their manufacturer-estimated life expectancy. Suboptimal placement of GPS antenna, combined with short satellite acquisition times and long fix intervals, were a likely cause of low fix-success rates and premature battery failures. Researchers wanting to employ lightweight GPS collars must be aware of current limitations and should carefully consider prospects of low fix rates and limited battery lives before deciding whether these units are capable of meeting study objectives.

Telemetry data have been widely used to quantify wildlife habitat relationships despite the fact that these data are inherently imprecise. All telemetry data have positional error, and failure to account for that error can lead to incorrect predictions of wildlife resource use. Several techniques have been used to account for positional error in wildlife studies. These techniques have been described in the literature, but their ability to accurately characterize wildlife resource use has never been tested. We evaluated the performance of techniques commonly used for incorporating telemetry error into studies of wildlife resource use. Our evaluation was based on imprecise telemetry data (mean telemetry error  =  174 m, SD  =  130 m) typical of field-based studies. We tested 5 techniques in 10 virtual environments and in one real-world environment for categorical (i.e., habitat types) and continuous (i.e., distances or elevations) rasters. Technique accuracy varied by patch size for the categorical rasters, with higher accuracy as patch size increased. At the smallest patch size (1 ha), the technique that ignores error performed best on categorical data (0.31 and 0.30 accuracy for virtual and real data, respectively); however, as patch size increased the bivariate-weighted technique performed better (0.56 accuracy at patch sizes >31 ha) and achieved complete accuracy (i.e., 1.00 accuracy) at smaller patch sizes (472 ha and 1,522 ha for virtual and real data, respectively) than any other technique. We quantified the accuracy of the continuous covariates using the mean absolute difference (MAD) in covariate value between true and estimated locations. We found that average MAD varied between 104 m (ignore telemetry error) and 140 m (rescale the covariate data) for our continuous covariate surfaces across virtual and real data sets. Techniques that rescale continuous covariate data or use a zonal mean on values within a telemetry error polygon were significantly less accurate than other techniques. Although the technique that ignored telemetry error performed best on categorical rasters with smaller average patch sizes (i.e., ≤31 ha) and on continuous rasters in our study, accuracy was so low that the utility of using point-based approaches for quantifying resource use is questionable when telemetry data are imprecise, particularly for small-patch habitat relationships.

The possible role of tag color in mediating behaviors that could bias resighting rate has not been examined. In a study that began in 2007, we marked 725 ring-billed gulls (Larus delawarensis) with Bondcote royal blue, green, yellow, or orange patagial tags. Reports we gathered over 2 years indicated approximately a 3.4∶1 bias in resighting rate toward yellow or orange tags. The observed bias is inconsistent with color-associated visibility bias or differential mortality among color-tagged breeding adults. Potential behavioral effects of tag color on individuals and conspecifics should be considered by biologists when planning marking studies.

We are unaware of any previous studies to evaluate using a sweep net to estimate abundance of red oak acorns (Quercus spp.) after they fall from tree crowns, sink to the ground in flooded bottomlands (i.e., sound acorns), and become potential food for animals or propagules for seedlings. We placed known numbers of white-painted red oak acorns of 3 size classes and used a sweep net to recover them in a flooded hardwood bottomland in Noxubee National Wildlife Refuge, Mississippi, USA. We recovered large acorns 1.96 and 1.32 times more often than small and medium acorns, respectively. Mean recovery rate of all marked acorns across size and density classes was 34.0 ± 7.0% (SE, n  =  9). Thus, sweep-net sampling for sound acorns in flooded oak bottomlands may yield negatively biased estimates of acorn abundance, and investigators should consider using correction factors.