A population of the grassland earless dragon (Tympanocryptis pinguicolla) on the Darling Downs, Queensland, Australia, had been considered extinct until its recent rediscovery. We determined factors affecting grassland earless dragon abundance and prey availability in 3 habitats. Mean dragon body condition and prey numbers were higher in sorghum than grasslands and grass verges. Poisson regression analyses indicated that the dragon numbers were 10 times higher in sorghum, and that this may result from differences in prey numbers as well as other habitat conditions. Tracking data indicated selection of open versus closed microhabitat. Sorghum planted in rows provided alternating open and closed microhabitats for optimal thermoregulation conditions. Grasslands and grass verges were more uniformly shaded. Of individuals we tracked in the sorghum stubble, 85.7% used litter as overnight refuges. Litter was abundant in sorghum and sparse in grass habitats. The practices of minimum tillage and resting stubble strips possibly mitigate agricultural impacts on dragons and provide continuous access to suitable habitat. Changes in agricultural practices that affect the habitat suitability will potentially have detrimental impacts on the population. Our data suggest that conservation efforts be focused on maintaining suitability of habitats in crop fields. We recommend monitoring dragon abundance at control and trial sites of any new agricultural practices; this will provide opportunity to modify or stop undesirable practices before adoption by farmers. Conservation agencies may use our data as a baseline for monitoring long-term viability of the population.

Wildlife managers depend on accurate information regarding wild turkey (Meleagris gallopavo) survival patterns to properly manage turkey populations. Survival patterns of male Rio Grande wild turkeys (M. g. intermedia) have not been studied intensively. Wildlife managers in the Texas Panhandle, USA, and southwestern Kansas, USA, suspected that turkey populations were declining. From January 2000 through August 2002, we studied survival and movement of 107 juvenile male and 115 adult male radiomarked Rio Grande wild turkeys on 4 study sites in the Texas Panhandle and southwestern Kansas. We predicted that males would experience lowest survival during spring and that there would be no difference in survival between age classes. We also predicted that greater male movement rates would lead to lower survival rates. Juvenile males had a higher annual survival rate (0.597 [95% CI hereafter: 0.478–0.716]) than adults (0.364 [0.257–0.472]). Juvenile male survival did not differ among seasons, with survival rates of 0.813 (0.736–0.891), 0.904 (0.837–0.972), and 0.917 (0.838–0.996) for spring, summer, and autumn, respectively. Adult male turkey survival was higher during summer (0.915 [0.859–0.972]) than during spring (0.725 [0.651–0.799]), autumn (0.671 [0.536–0.807]), and winter (0.792 [0.732–0.851]). Males had lower survival rates during seasons when long-distance movements were common. The annual survival rate for turkeys that moved to new core-use areas (0.383 [0.282–0.484]) was lower than that for turkeys that did not (0.535 [0.460–0.609]). Also, survival rates increased with time since relocation of core-use areas. Hunting accounted for 18.5% of all mortalities. However, most (80.7%) mortality was attributed to natural causes, mostly mammalian predation. We suspected most predation was the result of coyotes (Canis latrans) and bobcats (Lynx rufus). Managers in the northern portion of the natural range of Rio Grande wild turkeys should be aware of the presence of natural mortality factors that are evident in lightly hunted populations. Managers interested in increasing the survival of male Rio Grande wild turkeys should concentrate on efforts that will provide needed resources in close proximity to roosts.

During 1997 and 1998, we implemented a pilot investigation to compare survival, site fidelity, and reproductive characteristics of relocated wild northern bobwhites (Colinus virginianus) with that of resident birds. We captured wild bobwhites (n = 74) on managed lands in southern Georgia and relocated them (>1.6 km from capture sites) to sites nearby where density estimates revealed that population density was low compared to surrounding sites. We equipped translocated birds with radiotransmitters and released them in groups of 8–12. We also captured resident birds (n = 166) and simultaneously monitored them via radiotelemetry. We found no difference in survival (P = 0.82), nest production (P = 0.19), or nest survival (P = 0.85) between relocated and resident bobwhites. This suggests that relocating wild bobwhites does not negatively impact their survival or reproductive output. Based on the results of the pilot study, we implemented a large-scale relocation to determine whether relocation can increase native bobwhite populations. Following the pilot study, during 2000–2002, we relocated wild bobwhites (n = 202) within property boundaries to 3 different sites where population densities were low. Although only 2 sites experienced a significant population increase, hunting records suggested a positive population response for all sites where relocation occurred. Hence, relocation of wild bobwhites prior to breeding season may augment low-density populations, isolated populations, or voids within populations. The utility of translocation may facilitate preservation and conservation of the northern bobwhite by augmenting restoration efforts focused on habitat management, affording species preservation in isolated habitats, and increasing population dynamics and demographics via genetic enrichment.

Northern bobwhites (Colinus virginianus) have been declining in abundance throughout their range for several decades, and perhaps a century. Although wildlife biologists are well aware of this trend, most attempts to understand the declines have examined only a few local populations in a limited geographic area or have examined declines at a very large scale without reference to specific populations. Few studies use a standard protocol for examining trends in local populations throughout the entire natural range of bobwhites. I used the National Resources Inventory, a geographically extensive and intensive database on land cover and use, to characterize the composition and heterogeneity of landscapes inhabited by bobwhite populations that have been increasing (43 populations), decreasing (468), or become locally extinct (28). I tested bobwhite populations for overall positive or negative change, over the past 10 years or more, using data from the North American Breeding Bird Survey and a randomization test that controls for observer effects. Landscapes occupied by increasing and decreasing populations were, on average, different from one another in composition but not heterogeneity. As predicted, landscapes of decreasing populations tended to have a greater percentage of nonuseable land (e.g., urban and forestland) and a lesser percentage of useable land (e.g., cropland, pastures, and rangeland) as compared to landscapes where bobwhites actually increased. Moreover, landscapes where bobwhites had recently become extinct were different from those where bobwhites were only declining. In particular, a very large percentage of urban land characterized the landscapes of extinct populations. To some extent, landscapes of large (above average) and small (below average) populations also differed as predicted. The results do not point to a single universal explanation for bobwhite declines, but they do clearly show that declining populations inhabit local landscapes that, on average, are very different from those occupied by increasing populations. This knowledge may assist quail biologists and land managers to recognize the general type of landscape where the restoration of bobwhites may be most successful and where extant populations may be most threatened.

We evaluated the effect of habitat use and other sources of variation on survival of lesser prairie-chicken (Tympanuchus pallidicinctus) and greater prairie-chicken (Tympanuchus cupido) nests and broods. Daily nest and brood-survival probabilities were a function of a quadratic time trend, and both declined as the season progressed. Daily nest survival was negatively associated with nest age, and daily brood survival was positively associated with brood age. Lastly, broods tended by adult females had higher daily survival rates than broods reared by subadult females. The probability of a nest surviving from 10 May to 1 June was 0.72 (SE = 0.06). The probability of a brood surviving from 1 June to 30 July (hatch to 60 days posthatch) was 0.49 (SE = 0.19) and 0.05 (SE = 0.03) for broods reared by adults and subadults, respectively. Although nesting females and females with broods were using Conservation Reserve Program grasslands, there appeared to be no benefit to nest and brood survival during our study. Instead, age of the nest and brood, timing during the season, age of the brooding female, and precipitation during brooding were more important predictors of survival. Further experimentation is needed to determine the mechanisms responsible for decreased nest and brood survival throughout the season. Results from such research could be used to formulate management strategies to improve nest and brood survival.

The marbled murrelet (Brachyramphus marmoratus) is a threatened seabird that nests in old-growth forests in the Pacific Northwest. Despite concern for this species, little has been published on murrelet nesting habitat in the coast redwood (Sequoia sempervirens) region. Here we present the first comprehensive study of marbled murrelet nesting characteristics in redwood forests based on confirmed nest sites. In this study, we 1) described habitat characteristics at 17 murrelet nest sites in the Santa Cruz Mountains, California, USA, located using radiotelemetry and visual searches, and 2) compared nest sites with random sites located in nearby stands and centered on trees ≥120 cm diameter at breast height (dbh [potential nest trees or PNTs]). All 17 nests were located in stands of old-growth redwood forest and the mean dbh of nest trees was 210 cm (SD = 91 cm). Eighty-two percent of nests (90% of telemetry-found nests) were in unharvested stands and 18%, all on private property, had been lightly harvested but did not contain significantly fewer trees ≥120 cm dbh than unharvested nest sites. Twelve of 15 (80%) nests for which we were able to locate the nesting platform were on limbs and the remaining 3 (20%), all in redwood trees, were located on broken tops. Nest trees were significantly larger than PNTs and tended to be Douglas-fir (Pseudotsuga menziesii) despite the fact that nest stands were dominated by redwoods, perhaps because of greater nest platform availability in Douglas-fir trees. Nest sites were located closer to streams, had a greater basal area of trees ≥120 cm dbh, and were located lower on slopes than random sites based on analysis of variance models. We classified 71% of nest sites correctly with a simple logistic regression model that included only nest tree dbh and distance to stream—a model that could be used by managers in the region to identify potentially suitable nesting habitat. Our findings indicated that murrelets in central California, USA, primarily use old-growth redwood stands for nesting but will use partially harvested stands if a significant residual component remains; stands that have experienced some harvest but retain old-growth characteristics should be considered potential murrelet habitat in redwood forests.

Understanding the relationship between the annual reproductive success and changes in environment is important for appropriate waterfowl management. We developed predictive models of American black duck (Anas rubripes) production rates as a function of biotic (black duck and mallard [A. platyrhynchos] abundance) and abiotic factors (spring precipitation and temperature) across predefined breeding areas, from 1990 to 2001. We used male age ratios in the fall population, estimated from wing samples of harvested black ducks corrected for differential vulnerability via band-recoveries, as the index to annual reproduction. Information criteria suggested that a model containing predictors for density-dependence, competition with mallards, spring precipitation, and temperature and stratum-specific coefficients was the best model of black duck production rates. However, coefficients of this model were highly imprecise, leading to relatively poor predictive ability, possibly due to multicollinearity among predictors and the relatively short time span of analysis. We fit several models that included only black duck and mallard abundance as predictors; of these, models with constant slopes and stratum-specific intercepts performed best. Model-averaged parameter estimates supported inverse relationships between black duck and mallard abundance and age ratios, with stronger relative effects for black duck density-dependence. Both effects have implications for adaptive harvest management, in that harvest potential for black ducks may differ greatly depending on combinations of number of each species and the relative belief in alternative hypotheses about the impacts of mallards. Much variability in age ratios remained unexplained by our models, some possibly due to the lack of habitat explanatory variables but also apparently due to random factors. Model improvement could be achieved by incorporating recent developments in the modeling of random effects, especially via Markov Chain Monte Carlo methods. More research is also needed to incorporate recently acquired habitat predictors into predictive modeling for black ducks and other ducks breeding in eastern North America. These results provide critical input for models of adaptive harvest management, currently under consideration as an approach for developing an international (Canada–U.S.) harvest strategy for black ducks.

The population of dusky Canada geese (Branta canadensis occidentalis; hereafter duskies) breeding on the Copper River Delta (CRD), Alaska, USA, has been in long-term decline, largely as a result of reduced productivity. Estimates of renesting rates by duskies may be useful for adjusting estimates of the size of the breeding population derived from aerial surveys and for understanding population dynamics. We used a marked population of dusky females to obtain estimates of renesting propensity and renesting interval on the CRD, 1999–2000. Continuation nests, replacement nests initiated without a break in the laying sequence, resulted only after first nests were destroyed in the laying stage with ≤4 eggs laid. Renesting propensity declined with nest age from 72% in mid-laying to 30% in early incubation. Between first nests and renests, mean interval was 11.9 ± 0.6 days, mean distance was 74.5 m (range 0–214 m), and clutch size declined 0.9 ± 0.4 eggs. We incorporated our renesting estimates and available estimates of other nesting parameters into an individual-based model to predict the proportion of first nests, continuation nests, and renests, and to examine female success on the CRD, 1997–2000. Our model predicted that 19–36% of nests each year were continuation nests and renests. Also, through 15 May (the approx. date of breeding ground surveys), 1.1–1.3 nests were initiated per female. Thus, the number of nests per female would have a significant, though relatively consistent, effect on adjusting the relation between numbers of nests found on ground surveys versus numbers of birds seen during aerial surveys. We also suggest a method that managers could use to predict nests per female using nest success of early nests. Our model predicted that relative to observed estimates of nest success, female success was 32–100% greater, due to replacement nests. Thus, although nest success remains low, production for duskies was higher than previously thought. For dusky Canada geese, managers need to consider both continuation nests and renests in designing surveys and in calculating adjustment factors for the expansion of aerial survey data using nest densities.

We investigated the effect of recent habitat changes in California's Central Valley on wintering Pacific greater white-fronted geese (Anser albifrons frontalis) by comparing roost-to-feed distances, distributions, population range sizes, and habitat use during 1987–1990 and 1998–2000. These habitat changes included wetland restoration and agricultural land enhancement due to the 1990 implementation of the Central Valley Joint Venture, increased land area used for rice (Oryza sativa) production, and the practice of flooding, rather than burning, rice straw residues for decomposition because of burning restrictions enacted in 1991. Using radiotelemetry, we tracked 192 female geese and recorded 4,516 locations. Geese traveled shorter distances between roosting and feeding sites during 1998–2000 (24.2 ± 2.2 km) than during 1987–1990 (32.5 ± 3.4 km); distance traveled tended to decline throughout winter during both decades and varied among watershed basins. Population range size was smaller during 1998–2000 (3,367 km²) than during 1987–1990 (5,145 km²), despite a 2.2-fold increase in the size of the Pacific Flyway population of white-fronted geese during the same time period. The population range size also tended to increase throughout winter during both decades. Feeding and roosting distributions of geese also differed between decades; geese shifted into basins that had the greatest increases in the amount of area in rice production (i.e., American Basin) and out of other basins (i.e., Delta Basin). The use of rice habitat for roosting (1987–1990: 40%, 1998–2000: 54%) and feeding (1987–1990: 57%, 1998–2000: 72%) increased between decades, whereas use of wetlands declined for roosting (1987–1990: 36%, 1998–2000: 31%) and feeding (1987–1990: 22%, 1998–2000: 12%). Within postharvested rice habitats, geese roosted and fed primarily in burned rice fields during 1987–1990 (roost: 43%, feed: 34%), whereas they used flooded rice fields during 1998–2000 (roost: 78%, feed: 64%). Our results suggest that white-fronted geese have altered their spatial use of California's Central Valley during the past decade in response to changing agricultural practices and the implementation of the Central Valley Joint Venture.

Ospreys (Pandion haliaetus) have been the focus of conservation efforts since their dramatic population decline attributed to dichlorodiphenyltrichloroethane and related chemicals in the 1960s. Several recent studies of ospreys nesting in the United States have indicated improved reproduction. However, the density of breeding ospreys varies greatly among locations, with some areas seemingly habitable but not occupied. Because of concerns about pollution in the highly industrialized portions of the Delaware River and Bay, USA, we evaluated contaminant exposure and productivity in ospreys nesting on the Delaware River and Bay in 2002. We characterized habitat in the coastal zone of Delaware, USA, and the area around the river in Pennsylvania, USA, using data we collected as well as extant information provided by state and federal sources. We characterized habitat based on locations of occupied osprey nests in Delaware and Pennsylvania. We evaluated water clarity, water depth, land use and land cover, nest availability, and contaminants in sediment for use in a nest-occupancy model. Our results demonstrated that the presence of occupied nests was associated with water depth, water clarity, distance to an occupied osprey nest, and presence of urban land use, whereas a companion study demonstrated that hatching success was associated with the principal components derived from organochlorine-contaminant concentrations in osprey eggs (total polychlorinated biphenyls, p,p′-dichlorodiphenylethylene, chlordane and metabolites, and heptachlor epoxide). Our study provides guidelines for resource managers and local conservation organizations in management of ospreys and in development of habitat models that are appropriate for other piscivorous and marsh-nesting birds.

We studied the reproductive success of an urban–suburban red-tailed hawk (Buteo jamaicensis) population in southeast Wisconsin, USA, over a 14-year period, and we used productivity as a measure of habitat quality. Red-tailed hawk reproductive success for our study in southeast Wisconsin, USA, is consistent with other studies across North America, averaging 80.1% nesting success and 1.36 young per laying pair. Productivity for 1994 was significantly greater than other years. Red-tailed hawk productivity, an index of habitat quality, varied with habitat composition surrounding nest sites. Wetland area was the only habitat type that was significantly greater for low-productivity sites, indicating that wetlands were not beneficial for red-tailed hawk productivity in our study area. Urban habitat characteristics (i.e., area of roads and high-density urban land) were greater for high-productivity sites, and the landscape consisted of smaller habitat patches. This indicates that urban–suburban locations provided high-quality habitat for red-tailed hawks in our study area. Higher productivity in high-density urban areas suggests that the urban red-tailed hawk may be a source, not a sink, population in the metropolitan Milwaukee area. Increased nesting on human-made structures in urban locations and enhanced reproductive success for these nests reinforce this hypothesis and suggest that red-tailed hawks are adapting to this urban environment. Resource managers and urban land-use planners can incorporate high-quality red-tailed hawk habitat characteristics into urban land-use plans, thus insuring that individuals with increased fitness persist in this urban landscape.

The recent Eurasian collared-dove (Streptopelia decaocto, hereafter collared-dove) invasion of North America has raised concerns regarding its effects on native species, particularly mourning doves (Zenaida macroura). Our goal was to assess the potential for, and possible consequences of, foraging competition between mourning doves and collared-doves. We compared diet selection and measured degree of dietary overlap between the 2 dove species in a captive cafeteria experiment, and we measured aggression and competitive ability of these species in 3 captive competition experiments. We evaluated the effects of body size, temperature, and food distribution on aggression and competitive ability of both species, and we measured intraspecific aggression levels and competitive ability within each species. We found a high degree of dietary overlap between species; food preferences were similar between species, and Pianka's index of foraging-niche overlap was 0.95. Neither aggression nor competitive ability varied between species, however. Distribution of food in cafeteria experiments did not affect seed-preference results. Ambient temperature and body size of competitors had little effects on aggression or competitive ability of either species. Distribution of food in the environment affected aggression between species, however; aggression was greater in single (0.50 ± 0.10 interactions/min) than in multiple-patch (0.12 ± 0.02 interactions/min) trials. Collared-doves do not appear behaviorally more aggressive or competitively successful than mourning doves. Our results suggest that the potential for negative effects of collared-doves on mourning dove populations may be less than previously suspected, so control measures for collared doves may be unnecessary. However, competitive dynamics involving larger flocks of collared-doves and other potentially limiting resources must be considered.

The frequency of wild and prescribed fires in montane forests of the southwestern United States has increased after a century of fire suppression and subsequent fuels accumulation. To assess the effects of recent fires (median time since fire = 6 yr) on the montane forest bird community, we surveyed birds in 8 Sky Island mountain ranges in southeastern Arizona, USA, and examined how the distribution (i.e., presence–absence) of 65 species and relative abundance of 16 species correlated with evidence of severe and less severe fire at >1,500 survey points. We detected associations between fire and bird presence–absence for 17% of the 65 species analyzed and between fire and bird relative abundance for 25% of the 16 species analyzed. Most species (73%) were positively associated with burned areas and displayed stronger associations (i.e., more extreme odds ratios) with survey points that had evidence of severe as opposed to less severe fire. Positive associations with severe fire were strong (>3 to 1 odds) for western wood-pewee (Contopus sordidulus) and house wren (Troglodytes aedon), and negative associations with severe fire were strong for warbling vireo (Vireo gilvus) and red-breasted nuthatch (Sitta canadensis). Although recent fires appear to have had a positive effect on the distribution and relative abundance of several montane forest bird species in the region, these species are not the open-woodland birds that we would have expected to have benefited from fire based on previous research. Nevertheless, our results confirm associations between fire and bird presence–absence and relative abundance reported previously for 7 species of birds. Our results also provide new information for Grace's warbler (Dendroica graciae) and greater pewee (C. pertinax), 2 species for which fire data were formerly lacking. Managers can use these data to make and test predictions about the effects of future fires, both severe and less severe, on montane forest birds in the southwestern United States.

Although Swainson's warbler (Limnothlypis swainsonii) is typically associated with bottomland hardwood forests, they also breed in even-age pine (Pinus spp.) plantations. We used mist nets and point counts from 1998–2000 to survey intensively managed even-age loblolly pine (P. taeda) plantations of different age classes and management histories to determine breeding status and stand structure preferences of Swainson's warbler in southeastern Louisiana, USA. We detected Swainson's warblers in 23 of 124 sampled loblolly pine stands. We also confirmed breeding in 7–24-year-old pine stands. We found Swainson's warblers in pine stands that had well-developed canopy closure, abundant understory vegetation, and sparse live ground cover. Floristic differences between hardwood and pine breeding habitats demonstrate that Swainson's warblers do not require specific vegetation composition, although they discriminate within habitats based on physical structure of vegetation. Although management of Swainson's warblers has generally been directed at bottomland hardwood forests, widespread use of pine plantations may offer additional management opportunities for this species of concern.

Wildlife managers often have a good understanding of the threats faced by populations, but they need to know the intensity of management required for populations to survive. Managers therefore need quantitative projections for populations under different management regimes rather than just qualitative comparisons. However, quantitative projections are subject to tremendous uncertainty, particularly for small populations monitored for short time spans. We assess the level of predator control needed for a reintroduced population of North Island robins (Petroica longipes) to grow, accounting for uncertainty associated with parameter estimation, model structure, and demographic stochasticity. The robin population grew when exotic rats were reduced to low levels (<10% of footprint tunnels tracked in 24 hr) by regular maintenance of poison bait stations. However, the population declined after baiting was stopped 3 years after the reintroduction (March 2002), and it had fallen to 4 pairs by September 2004. We created a simulation model incorporating relationships between vital rates (survival and fecundity) of the robin population and rat tracking rate estimated from 5 years of data. We ran the model 10,000 times at each rat tracking rate, with vital rates sampled from distributions (defined by estimates and standard errors) at the start of each run. Output from a deterministic model suggested that λ (finite rate of increase) would be >1 if rat tracking were <20%, and up to 1.2 with rat tracking at 1%. However, 95% confidence intervals for λ extended <1 at any tracking rate. With demographic stochasticity added, there was >20% probability of further decline in 5 years even when the expected λ was 1.2. With all forms of uncertainty included, 41% of simulations projected a further decline over 5 years if the rat tracking rate were 10%. This proportion was reduced to 30% if initial population size was increased to 20 pairs. Our analysis therefore showed it was most likely that the robin population would grow if intensive rat control were reinstated, particularly if the population was supplemented, but there was substantial risk the population would continue to decline under such management.

The introduction of rats and other mammalian predators has caused many New Zealand species to decline. Predator control is now being used to reverse these declines in selected mainland areas, and a footprint-tracking index is used to assess effectiveness of control. To assess the meaning of this index for native populations, it is necessary to model the functional relationships between predator-tracking rates and vital rates of native populations. We monitored North Island robins (Petroica longipes) for 5 years after reintroduction to Paengaroa Mainland Island, and rat levels changed dramatically over this period due to changes in management policy. We used the resulting data to model how vital rates varied with rat tracking, using Akaike's Information Criterion to compare alternative models for each vital rate. We fitted survival models to mark–resighting data obtained in tri-annual surveys of the reserve, and we fitted fecundity models to data on numbers of independent young produced by individual females. The best model for annual adult survival was ŝ = 0.64p^0.24F where p is the complement of the tracking rate (i.e., 0 = 100% tracking) and F is sex (0 = male, 1 = female). The best model for annual fecundity per female was where U is the female's pairing status (0 = paired, 1 = unpaired). For juvenile survival (from independence to adulthood), it was ambiguous whether survival was constant (ŝ = 0.39) or changed with rat levels (ŝ = 0.49p^0.58). We used the delta method to obtain a 95% confidence interval for each vital rate at any rat tracking rate. The models allow the growth of the population to be projected at any tracking rate, and they provide a starting point for projecting growth of any population in relation to a predator-control index.

Human activities can change the spatial distribution of individuals within wildlife populations that in turn alters population allele frequencies and spatial genetic structure at fine scales. Artificial feeding is one such activity whose impact on wildlife physical condition, population dynamics, and transmission of disease has been well documented. To evaluate the impact of artificial feeding on the spatial distribution and social organization of white-tailed deer (Odocoileus virginianus) we estimated allele frequencies at 3 microsatellite loci for 2,177 hunter-harvested deer and characterized microgeographic genetic structure in 2 regions of the northeast lower peninsula of Michigan, USA, during and following cessation of artificial feeding. While artificial feeding was ongoing we observed no evidence of spatial genetic structure across either region. Spatial homogeneity of allele frequencies over such a large area was surprising given numerous studies that have documented spatial genetic structure in other deer populations, and it was likely a function of the aggregation of multiple kin-structured social groups (i.e., matrilines) at artificial feeding sites. Subsequently, when artificial feeding was banned, we found significant genetic differentiation among groups of deer in both regions. Detection of microgeographic genetic structure consistent with a pattern of isolation-by-distance following the ban on artificial feeding was likely the result of increased spatial segregation of social groups of related deer. Our results illustrate how analyses of the degree to which natural populations are spatially genetically structured can be used to infer the effects of human actions on wildlife movement patterns, breeding behaviors, and disease transmission that are difficult to determine using traditional methods.

The understanding of population dynamics is a central issue for managing large mammals. Modeling has allowed population ecologists to increase their knowledge about complex systems and better predict population responses to diverse perturbations. Mountain goats (Oreamnos americanus) appear sensitive to harvest, but the relative influence of survival and reproductive rates on their population dynamics are not well understood. Using longitudinal data on age- and sex-specific survival and reproduction from a marked mountain goat population in Alberta, Canada, we built a stage-class matrix model to predict short-term numerical changes for 11 other goat populations in Alberta for which the only data available were from annual aerial surveys. Overall, the model provided an acceptable fit to changes in population size for 8 of 12 populations. Temporal trends in population size were underestimated in 2 populations and overestimated in another 2, suggesting that these populations had different vital rates than those of the intensively studied population. Sensitivity analyses revealed that the survival of mature females (aged 5 yr and older) had the greatest elasticity for population growth. Modeled management scenarios indicated that nonselective yearly harvest rates above 1% of goats aged 2 years and older were not sustainable over the short-term for some populations. The simulations also revealed that small (n = 25) and medium-size (n = 50) populations, which correspond to most goat populations in Alberta, had high extinction risk (18 to 82% over 40 years), even in the absence of harvest. Our results confirm that mountain goat populations are very sensitive to harvest, indicate that wildlife managers should prevent female harvest, and suggest that although a high demand for goat hunting exists in Alberta, most populations in this province—and probably small populations elsewhere—cannot withstand exploitation.

The influence of environmental and human factors on group sizes of large ungulates is still poorly understood, especially when considered at multiple timescales. We analyzed long-term data of red deer (Cervus elaphus) group sizes collected at 3 timescales in Białowieża Primeval Forest, Poland, from 1986 to 2003. On the daily scale, group size differed among periods of the day for females in summer (P = 0.001) and autumn (P = 0.04) but not winter (P = 0.18). Group size of males did not differ (P > 0.35) among the periods of day during any season. On the seasonal scale, both sexes had larger group sizes in winter than summer, and males were always more solitary than females. At the annual scale, multiple-regression analysis explained 96% (r² = 0.957) of deer grouping patterns. Human hunting had the greatest influence (sr²_i = 0.414), followed by acorn crop (sr²_i = 0.012) and snow cover (sr²_i = 0.008). Intense hunting by humans during a 5-year period appeared to cause increases in group sizes, even while red deer densities decreased. The disruption of the normally positive relationship of deer density to group size apparently affected predator–prey relationships, consequently red deer numbers continued to decline even after hunting pressure was relaxed. Our results indicate caution should be used when reducing red deer numbers by dramatic increases in hunting because the resulting behavioral and ecological changes in deer have implications that extend well beyond the season and year, with important consequences for the long-term stability of the population, especially in areas where large carnivores are present.

We researched the environmental attributes (n = 28) associated with elk (n = 50) summer range (1 May–30 Sep) in the central Black Hills of South Dakota, USA, during 1998–2001. We defined high-use areas or centers of activity as landscapes underlying large concentrations of elk locations resulting from the shared fidelity of independently moving animals to specific regions on summer range. We divided the study area into 3-km grid cells to represent the distance elk travel in a 24-hour period. We computed mean elevation and slope, proportion and configuration of overstory canopy cover, proportion and configuration of dominant vegetation type, estimated biomass, road density, traffic rate, and amount of habitat not dissected by improved surface roads for each cell. We used a combination of multiple stepwise regression and likelihood ratio tests to develop spatially adjusted models with total number of elk locations per cell as the dependent variable. Environmental attributes varied in their significance based on their availability to different elk subpopulations. Collectively, the number of elk locations was positively associated (model r² = 0.50, P < 0.001) with elevation, proportion of non–road-dissected habitat, shape complexity of meadows, proportion of forest stands with ≤40% overstory canopy cover, and proportion of aspen (Populus tremuloides). Elk were responsive to a landscape structure emphasizing forage potential, and their selection was based on the composition and pattern of both biotic and abiotic variables. Defining the characteristics of high-use areas allows management to manipulate landscapes so as to contain more of the habitats preferred by elk.

We compared selection of northern Yellowstone elk (Cervus elaphus) by hunters in the Gardiner Late Hunt and northern Yellowstone wolves (Canis lupus) with regard to sex, age, and impacts to recruitment. We compared harvest data from 1996–2001 with wolf-killed elk data from 1995–2001. We assessed the effects of hunting and wolf predation on reproductive female elk by constructing a life table and calculating reproductive values for females in the northern Yellowstone herd. We devised an index of total reproductive impact to measure impacts to calf production due to hunting and wolf predation. The age classes of female elk selected by wolves and hunters were significantly different. Hunters selected a large proportion of female elk with the greatest reproductive values, whereas wolves selected a large proportion of elk calves and older females with low reproductive values. The mean age of adult females killed by hunters throughout the study period was 6.5 years, whereas the mean age of adult females killed by wolves was 13.9 years. Hunting exerted a greater total reproductive impact on the herd than wolf predation. The combined effects of hunters killing prime-aged females (2–9 yr old), wolves killing calves, and predation by other predators has the potential to limit the elk population in the future. Yellowstone is unique in this regard because multiple predators that occur sympatrically, including hunters, wolves, grizzly bears (Ursus arctos), black bears (Ursus americanus), cougars (Felis concolor), and coyotes (Canis latrans), all prey on elk. Using an Adaptive Harvest Management process the known female elk harvest during the Gardiner Late Hunt has been reduced by 72% from 2,221 elk in 1997 to 620 elk in 2004. In the future, hunting harvest levels may be reduced further to partially offset elk losses to wolves, other predators, and environmental factors.

Wolves (Canis lupus) have expanded their distribution into areas of the midwest United States that have not had wolves for several decades. With recolonization of wolves into agricultural areas, there is increasing concern of wolf–livestock conflicts. To assess the risk wolves may pose to livestock, we initiated a 3-year study investigating the activity patterns, movements, habitat use, visitation to livestock pastures by wolves, and the occurrence of depredation events in an agricultural–wildland matrix in northwestern Minnesota, USA. From June 1997 to November 1999, we captured 23 wolves, including pups, from 3 packs; we radiocollared 16 of these wolves. We tracked radioed wolves intensively on a 24-hour basis during the spring, summer, and autumn of 1998 and 1999. We found wolves passed directly through a pasture containing cattle on 28% of the nights of tracking; 58% and 95% of the wolf locations were ≤1 km and ≤5 km from a pasture, respectively. Space use of wolves showed that while they visited livestock pastures during the 24-hour tracking sessions, they apparently were passing through these pastures with cattle and not preying on livestock. When compared to random simulations of movements, wolves appeared to encounter livestock pastures randomly. Thirty percent of random movements passed directly through a pasture; 65% and 95% of random movements were within ≤1 km and ≤5 km of a pasture, respectively. Wolves were more active at night than during the day. Wolves avoided pastures during the day and visited pastures at night when depredations were most likely (i.e., human presence was low). Visitation of livestock pastures was not related to any discernible characteristics of the pastures (i.e., pasture size, cattle density, distance to human habitation, percent forest cover, index of deer abundance). However, pastures in which livestock were killed by wolves contained more cattle than pastures without depredations, but in 1998 only. While the risk of wolf predation on livestock was potentially high (wolves were within ≤1 km of a pasture on 58% of nights), few livestock were actually killed. During the 3-year study, only 8 animals (all young or vulnerable livestock) were depredated by wolves. Maintaining healthy wild prey populations, removing offending wolves that kill livestock, and encouraging effective and proper husbandry practices (e.g., disposal of carcasses) among livestock producers, should allow for the persistence of wolves in northwestern Minnesota, USA, while minimizing their impact to farmers in this agriculture–wildland matrix.

Resolving conflicts between predators and livestock producers depends on obtaining reliable information about the predators that kill livestock. We used salivary DNA obtained from attack wounds on domestic sheep carcasses to identify the species of predator responsible for the kill, as well as the sex and individual identity of coyotes (Canis latrans) that killed sheep. Coyotes killed 36 of 37 depredated sheep. Breeding pairs whose territories overlapped sheep grazing areas were the primary predators on domestic sheep, and only breeding pairs killed multiple sheep. Breeding males, acting alone or with their mate, were involved in 21 of 25 kills. Breeding females participated in 13 kills, but only 1 breeding female killed sheep on her own. Transient females did not kill sheep, and both kills by transient males occurred in territories with a breeding vacancy. Our results suggest that predator control should be targeted at breeding male coyotes. Salivary DNA is a potentially powerful means of both investigating predation patterns and evaluating the effectiveness of control at targeting individuals that kill livestock.

The black bear (Ursus americanus) population at White River National Wildlife Refuge is isolated and genetically distinct, but hunting occurs adjacent to refuge boundaries and females with cubs are removed annually for a reintroduction project. We trapped and radiotracked bears to determine level of exploitation and compare methods for estimating population growth and sustainability. We captured 260 bears (113 M:147 F), 414 times, from 1998 through 2003. Survival estimates based on radiotracking and mark–recapture indicated that hunting and translocations were significant sources of loss. Based on mark–recapture data (Pradel estimator), the annual population growth rate (λ) averaged 1.066 (SE = 0.077) when translocation removals occurred and averaged 0.961 (SE = 0.155) when both harvest and translocations occurred. Estimates of λ based on a population simulation model (program RISKMAN) averaged 1.061 (SD = 0.104) and 1.100 (SD = 0.111) when no removals occurred, 1.003 (SD = 0.097) and 1.046 (SD = 0.102) when translocations occurred, and 0.973 (SD = 0.096) and 1.006 (SD = 0.099) when both harvest and translocations occurred, depending on the survival rate estimates we used. The probability of population decline by >25% over a 10-year period ranged from 13.8 to 68.8%, given our estimated removal rates. We conclude that hunting and translocation losses are at or exceed the maximum the population is capable of sustaining. Although extinction risks of this important bear population are low over the near term, it should continue to be closely monitored by state and federal agencies. The mark–recapture method we used to estimate λ proved to be a reliable alternative to more costly population modeling methods.

Understanding how culling practices impact target populations is essential in identifying optimum strategies for controlling population size. Red fox (Vulpes vulpes) populations are subject to attempted control throughout much of their range due to their impacts on livestock and game, and disease transmission (e.g., rabies); however, the efficacy of different methods in controlling fox populations is low. For mesomammal species, experimental approaches are often limited by issues of scale. We used an individual-based, spatially explicit population model to investigate the efficacy of different culling practices in artificial landscapes. Model outputs were the number of social groups, the fox population before and after breeding, the extent of successful dispersal within the landscape, and the number of migrants out of the landscape. We investigated 4 different population management strategies using our model: 1) hunting with hounds, 2) winter shooting, 3) culling at the den in spring, and 4) fertility control. Population density in the absence of control was most strongly related to carrying capacity and the extent of immigration from surrounding fox populations. Culling at the den was most successful at suppressing fox populations, while fertility control was least effective, but the effect depended on the carrying capacity of the landscape. We conclude that effective control of populations at landscape scales (e.g., 1,600 km²) is not feasible or practical unless immigration from outside populations is low or can be controlled. These results can be used to inform policy on the management of United Kingdom (UK) fox populations and contribute to the ongoing debate on hunting with hounds as practiced in the UK.

Red foxes (Vulpes vulpes), raccoons (Procyon lotor), and striped skunks (Mephitis mephitis) are found throughout the United States, wherever there is suitable denning habitat and food resources. Densities of these predators have increased throughout the Intermountain West as a consequence of human alterations in habitat. Within the Bear River Migratory Bird Refuge (hereafter, refuge), in northern Utah, USA, upland nesting habitat for ducks is limited to the levee banks and roadsides. Red foxes, raccoons, and striped skunks, which prey on upland nesting birds, are also abundant on the refuge. We studied red foxes, raccoons, and striped skunks' use of levees and the edges associated with them within a wetland environment. Red fox, raccoon, and striped skunk locations were negatively correlated with distance to the nearest dike (−0.78, −0.69, and −0.45, respectively). Animals incorporated more roads and/or levees into their home ranges than expected by chance (x̄ = 2.6; Z < 0.001); incorporation of levees was greater during the dispersal season than the rearing season (P = 0.03). Skunk home ranges (average size, 3.0 km²) were oriented along roads and levees (P = 0.03), whereas raccoon (average size, 3.6 km²) and fox home ranges (average size, 3.5 km²) were not (P = 0.93, P = 0.13, respectively). Fox home ranges in the refuge were more oblong in shape than reported elsewhere (P = 0.03). However, home-range shapes of raccoons and striped skunks were similar to previous studies (P = 0.84, P = 0.97, respectively). The use of roads and levees within the refuge increases the possible travel distance and penetration of predators into wetland environments. This contributes to increased depredation of waterfowl nests and to decreased recruitment. Managers of similar areas might decrease depredation of waterfowl by disrupting the linear pattern of corridors, thereby decreasing the congestion of animal roads and levees. This would, then, decrease the encounter rates of predators and prey.

Predation by feral cats (Felis catus) is believed to threaten the conservation of a range of terrestrial vertebrates in southeastern Australia, and new baiting techniques are sought for broad-scale control of feral cats. In southeastern Australia there are 34 native mammals that may consume meat baits, and ways to minimize their exposure to bait toxicants are needed. We determined the potential of cats to ingest larger particles relative to most nontarget species as a mechanism to increase baiting selectivity. Feral cats reliably ingested inert, spherical bearings up to 4.7 mm in diameter when the bearings were implanted within a specialized bait medium. Presence of bearings did not affect bait consumption relative to untreated baits. Repetitive ingestion was highly reliable in the first 9 days of a feeding trial and diminished only marginally in a consecutive trial. We presented captive plains rats (Pseudomys australis), fat-tailed dunnarts (Sminthopsis crassicaudata), eastern barred-bandicoots (Perameles gunnii), and northern quolls (Dasyurus hallucatus), with baits containing 4.7-mm-diameter coated pellets formulated with the marker dye rhodamine B (RB). Exposure to the marker dye for each species was not biased to individual or day of presentation. Exposure to RB in the pellet occurred in only 3.1–6.5% of presentations for each species, and the mean daily mass of the pellet in g kg⁻¹ day⁻¹ ingested was 0.078–0.01% of the mean bait mass in g kg⁻¹ day⁻¹ consumed. Pellet presentation greatly reduced (P ≤ 0.001) the exposure of wild native rodents to RB relative to directly injected baits. Exploiting differential particle size ingestion between feral cats and nontarget species could potentially reduce exposure of many nontarget mammals to bait toxicants and decrease the risk of baiting to nontarget species.

The European wild rabbit (Oryctolagus cuniculus) is the main prey for several endangered species and an important game species in the Iberian Peninsula. However, over the last several decades 2 diseases, myxomatosis and rabbit hemorrhagic disease (RHD), have contributed to a decline in rabbit populations. In Spain, vaccination campaigns against both diseases and the translocation of vaccinated rabbits are frequently used in projects aimed at stimulating the recovery of wild populations. We estimated which factors related to body condition were associated with successful immunization by vaccination. In 191 adult wild rabbits, we calculated a body-mass index and analyzed a number of biochemical parameters and antibody concentrations before and after vaccination. Results showed that, respectively, 81 and 84% of initially seronegative rabbits seroconverted after vaccination against myxomatosis and RHD. We also found that RHD antibody concentrations after vaccination were positively associated with total protein concentrations at the moment of vaccination in all rabbits, whereas RHD antibody concentrations were negatively related to the creatinine concentration at the end of our study for initially seronegative rabbits. Our results suggested that in wild rabbits vaccination was an effective way of increasing antibody concentrations and, thus, of fighting myxomatosis and RHD, although the intensity of the immune response was conditioned by the body condition of individual rabbits. Consequently, rabbit translocations could be improved by avoiding the translocation of individuals with poor body condition and by improving vaccination protocols. In addition, success rates in mass vaccination programs carried out in free-living wild populations may be increased if the body condition of individuals is evaluated before vaccination campaigns are carried out.

Age-related variation in morphometry has been documented for many species. Knowledge of growth patterns can be useful for modeling energetics, detecting physiological influences on populations, and predicting age. These benefits have shown value in understanding population dynamics of invasive species, particularly in developing efficient control and eradication programs. However, development and evaluation of descriptive and predictive models is a critical initial step in this process. Accordingly, we used data from necropsies of 1,544 nutria (Myocastor coypus) collected in Maryland, USA, to evaluate the accuracy of previously published models for prediction of nutria age from body weight. Published models underestimated body weights of our animals, especially for ages <3. We used cross-validation procedures to develop and evaluate models for describing nutria growth patterns and for predicting nutria age. We derived models from a randomly selected model-building data set (n = 192–193 M, 217–222 F) and evaluated them with the remaining animals (n = 487–488 M, 642–647 F). We used nonlinear regression to develop Gompertz growth-curve models relating morphometric variables to age. Predicted values of morphometric variables fell within the 95% confidence limits of their true values for most age classes. We also developed predictive models for estimating nutria age from morphometry, using linear regression of log-transformed age on morphometric variables. The evaluation data set corresponded with 95% prediction intervals from the new models. Predictive models for body weight and length provided greater accuracy and less bias than models for foot length and axillary girth. Our growth models accurately described age-related variation in nutria morphometry, and our predictive models provided accurate estimates of ages from morphometry that will be useful for live-captured individuals. Our models offer better accuracy and precision than previously published models, providing a capacity for modeling energetics and growth patterns of Maryland nutria as well as an empirical basis for determining population age structure from live-captured animals.

Douglas-fir dwarf mistletoe (Arceuthobium douglasii) is a prevalent species in southwestern mixed-conifer forests, affecting host trees by reducing growth and seed production and increasing mortality. Dwarf mistletoe infections can also form witches' brooms, which are profusely branched, dense masses of distorted host branches in the crowns of infected trees. Despite their impact on trees, brooms provide nesting, roosting, and foraging habitat for many wildlife species. To determine whether red squirrels (Tamiasciurus hudsonicus) selected brooms for nesting, foraging, or caching sites, we compared use of brooms in Douglas-fir (Pseudotsuga menziesii) in mixed-conifer forests in northern Arizona and New Mexico, USA, in 1998 and 1999. Douglas-fir brooms are classified into 3 distinct forms based on structure and point of origin on the tree. Type I brooms form from an infection near the terminal end of a branch. Type II brooms form from an infection ≤1 m from the tree trunk (bole); the supporting branch usually grows vertically from the point of infection, parallel to the bole. Type III brooms result from an infection on the bole, creating a dense profusion of branches and often forming a platform. We selected trees of 3 size classes (10–25-, 26–40-, >40-cm dbh) from stands and examined them for signs of red squirrel use (e.g., nesting, food storage). Red squirrels selected Type II and III brooms located closer to the bole and with larger platform size for nesting. They selected Type II and III over Type I brooms for caching and foraging use. Retaining Type II and III brooms that have platforms >700 cm², volumes >15 m², and are located 4.5–10 m above ground will retain this habitat element for red squirrels.