Have Lesser Scaup, Aythya affinis, Reproductive Rates Declined in Parkland Manitoba?

Long-term surveys indicate that the scaup populations have declined over the past 20 years, and that this is probably the result of decreases in Lesser Scaup (Aythya affinis) rather than Greater Scaup (Aythya marila) numbers. To identify factors possibly related to the decline, we estimated demographic parameters for a local population of Lesser Scaup at Erickson, Manitoba, that was well studied before declines occurred and compared these estimates to historic rates. On average, nests were initiated later than in the past, and recent estimates of nesting success and duckling survival were lower than historical estimates. Breeding-season survival of adult females was estimated as 72.6%, with most (83%) mortality occurring during nesting. Current estimates of demographic rates at Erickson are too low to maintain a stable local population, and suppressed reproductive rates might be the proximate cause of the local population decline

Using Occupancy Surveys to Assess Summer Resource Selection of Sympatric Bighorn Sheep and Mountain Goats in Northern Yellowstone

Both bighorn sheep and mountain goats are generalist herbivores that overlap extensively in broad food and habitat requirements, but there have been few studies examining the potential for competition between sympatric populations. One area in which native bighorn sheep are living in sympatry with non-native mountain goats is the southern Gallatin Mountain range within and adjacent to the northwest boundary of Yellowstone National Park. Existing data of bighorn sheep and mountain goat observations for the area vary in spatial precision and records of areas where observers looked for but did not detect animals are not available. To gain a better understanding of the relationship between bighorn sheep and mountain goats and their habitat, it is necessary to understand resource selection and the extent of overlap in resource use among sympatric populations on fine spatial and temporal scales. In order to meet this need we designed and implemented formal, ground-based occupancy surveys during the summer of 2011. A crew of four spent 113 observer days in the field and hiked approximately 210 miles recording presence-absence data for both mountain ungulates. A total of 6,932 sample units were surveyed, with 68 bighorn sheep and 95 mountain goat groups detected. Detection probabilities for bighorn sheep and mountain goats were 66.9% and 54.5% respectively. We summarize the objectives and field design of the project and report on our efforts to develop enhanced habitat models which will provide managers with additional ecological insights

Meta-Analysis of Relationships between Human Offtake, Total Mortality and Population Dynamics of Gray Wolves (Canis lupus)

Following the growth and geographic expansion of wolf (Canis lupus) populations reintroduced to Yellowstone National Park and central Idaho in 1995–1996, Rocky Mountain wolves were removed from the endangered species list in May 2009. Idaho and Montana immediately established hunting seasons with quotas equaling 20% of the regional wolf population. Combining hunting with predator control, 37.1% of Montana and Idaho wolves were killed in the year of delisting. Hunting and predator control are well-established methods to broaden societal acceptance of large carnivores, but it is unprecedented for a species to move so rapidly from protection under the Endangered Species Act to heavy direct harvest, and it is important to use all available data to assess the likely consequences of these changes in policy. For wolves, it is widely argued that human offtake has little effect on total mortality rates, so that a harvest of 28–50% per year can be sustained. Using previously published data from 21 North American wolf populations, we related total annual mortality and population growth to annual human offtake. Contrary to current conventional wisdom, there was a strong association between human offtake and total mortality rates across North American wolf populations. Human offtake was associated with a strongly additive or super-additive increase in total mortality. Population growth declined as human offtake increased, even at low rates of offtake. Finally, wolf populations declined with harvests substantially lower than the thresholds identified in current state and federal policies. These results should help to inform management of Rocky Mountain wolves

Occupancy Dynamics, Roost Habitat and Prey of Mexican Spotted Owls in Utah

Mexican spotted owls (Strix occidentalis lucida) occupy canyon habitats that have received less attention than owls in forested environments, and yet canyon environments represent a significant portion of the owl’s range. In Utah, the owls occupy narrow and steep-walled canyons that attract high levels of human use, including climbing and hiking through nest areas, and human use levels have strongly increased in the canyons, for example, permits for access to popular climbs and hikes increased over 1700% during 1998 to 2002 in Zion National Park. To examine potential effects of recreation on the owls, we studied temporal variability of detection, occupancy, local extinction, and colonization probabilities. Our study sites included several National Parks and BLM resource areas. Our primary objective was to examine effects of recreation on site occupancy dynamics. We also investigated reproductive success, roost habitat, and prey selection. The analysis of detection rate showed strong support for constant detection probability of 89% for spotted owls among 47 sites. For both single owls and owl pairs we estimated initial occupancy rate of 83% for mesic sites and 43% for relatively xeric sites. We found that recreation was not associated with occupancy, detection, nor extinction and recolonization probabilities. Although reproductive rates varied by year, recreation was not negatively associated with production of fledgling owls per site. We also studied prey selection and roost habitat in the canyon environments. Roosts were placed on steep-walled cliffs with greater number of perches than adjacent habitats, and roosts possessed relatively high overhead tree cover, cool daytime temperatures, and thus a suitable thermal environment in the arid canyons. Pellets collected at roosts sites, upon dissection, indicated that rodents were primary prey, but also included birds, bats, and various anthropods. Woodrats (Neotoma sp.) dominated the prey frequency and biomass

Winter Wheat- Finding a Balance Between Modern Agriculture and Prairie Nesting Ducks

The Prairie Pothole Region (PPR) of North America is a highly valuable landscape for breeding waterfowl that has been predominantly converted to some form of agriculture in the last century. This is cause for concern since the extent of cropland has been strongly associated with declining numbers and nest success of ducks. With the recent increase in economic value of some cash crops and the potential to lose highly valuable nesting habitat in the Conservation Reserve Program (CRP), there has been an interest in evaluating alternative farming practices as potential breeding habitat for waterfowl. While past research has shown nest success of waterfowl to be very low in spring-seeded crops, limited research has assessed the potential of winter wheat, a fall-seeded crop, as a nesting habitat. We wanted to assess and compare the use and success of prairie-nesting ducks in winter wheat to perennial cover (CRP, grassland, etc.) in the PPR of North Dakota. We monitored duck nests (Anas spp.) in winter wheat (n = 1284) and perennial cover (n = 3244) from 2010-2012. We will use a model-selection based approach to evaluate nest survival after accounting for a variety of environmental (wetland density, vegetation density, etc.) and temporal covariates (initiation date, nest age, etc.) and predict that daily nest survival will be similar in both habitats. Results from this study will provide valuable insight for wildlife managers on the benefits and weaknesses of winter wheat as a breeding habitat for waterfowl

One-Year Progress Report for the Montana Statewide Bighorn Sheep Research Project

Restoration and conservation of bighorn sheep has been a challenge. Despite strong conservation efforts, bighorn sheep have not recovered to historic range and numbers as most other ungulates have. The Montana Statewide Bighorn Sheep Research Project, a collaborative effort between Montana Department of Fish Wildlife & Parks and Montana State University, began operations in winter 2013/2014 in order to provide information to help guide future management and conservation of bighorn sheep. Seven bighorn sheep populations were scheduled to be sampled in the first year of the study and this presentation will outline the accomplishments, challenges, and findings from the first year of the research effort. Research objectives are to quantify and compare exposure to and prevalence of pneumonia pathogens, body condition, habitat use and demographic rates in multiple bighorn sheep populations with varying histories and characteristics across Montana.  Study plans and initial findings relevant to these objectives will be presented

Modeling Daily Nest Survival of Five Woodpecker Species in Relation to a Mountain Pine Beetle Epidemic Near Helena, MT

Forested ecosystems of Western North America have experienced increased periodicity and severity of disturbances in recent years. Large-scale mountain pine beetle (Dendroctonus ponderosae) epidemics affecting hundreds of thousands of forested hectares in the American and Canadian Rockies have been attributed to favorable climatic conditions. Ecosystem processes of these forested landscapes are potentially becoming altered. Wildlife responses, however, to beetle disturbance are not yet well understood. Because of their sensitivity to changes in forest conditions, as well as their ability to create valuable habitat for several other forest-dwelling species, our study focused on woodpeckers as disturbance specialists. Owing to differences among life history characteristics, we grouped 5 focal woodpecker species into three assemblages based on feeding and habitat requirements and predicted responses to beetle epidemic conditions. Based on a priori hypotheses, we modeled daily nest survival (DSR) of each assemblage as a function of several temporal and spatial covariates, including remotely sensed data, abiotic factors, and beetle epidemic conditions at two spatial scales. To rank the support for each candidate model, we used Akaike’s Information Criterion corrected for small sample size (AICc) and used the principle of parsimony to arrive at a final inferential model. Results suggest that abiotic weather and local habitat features were important to include in models of DSR, whereas a number of other covariates containing information about the timing and nature of the beetle epidemic were not useful. Our results will inform management activities for post-beetle forests that will help maintain habitat of disturbance specialist species

Montana’s New State-Wide Bighorn Sheep Research Initiative

Bighorn sheep (Ovis canadensis) conservation and management in Montana has been, and continues to be, a challenge. The majority of Montana’s bighorn sheep populations are patchily distributed across the state and are relatively small, with many populations static or periodically experiencing dramatic declines despite the fact that adequate habitat seems to be abundant. Wildlife managers and biologists are routinely making decisions on bighorn sheep population augmentation and restoration, harvest, habitat management, disease prevention and response, and other conservation actions without adequate knowledge of the drivers of demographic processes that inform management of many of Montana’s more successfully restored ungulate species. Field studies of bighorn sheep in Montana have been limited primarily to short-term, master’s thesis projects focused on a specific herd. A 6-yr research program has been designed and funded on the premise that research insights that are broadly applicable for management and conservation are best obtained by addressing the same questions in multiple populations representing differing demographic characteristics, ecological settings, and management histories that capture the range of variation realized by the species of interest. The research program will involve field studies of seven bighorn sheep herds in Montana, with data on each herd collected over a 5-yr period. Herds were selected to capture a wide range of variability in disease outbreak history, habitat types, and herd attributes in an effort to maximize our ability to partition and quantify the potential relative effects of these factors on lamb and adult survival, recruitment, and population dynamics

Distribution of Breeding Ducks Relative to Habitat Characteristics in the Prairie Pothole Region of North Central Montana

Continental waterfowl population declines in the early 1980s led to the development and implementation of the North American Waterfowl Management Plan.  The plan identified wetland and grassland losses in the Prairie Pothole Region (PPR) of Canada and the United States as the major causes of low continental duck populations.  Until 2008, north central Montana was the only remaining PPR area in the United States without a ground-based annual survey to monitor breeding duck populations and quantify breeding duck habitat.  The purpose of this study was to establish an annual breeding duck survey in north central Montana to 1) develop species-specific breeding pair predictive models, and 2) apply the models to estimate the distribution of breeding ducks and identify priority areas for conservation.  We observed 10539 indicated breeding duck pairs on approximately 675 wetland basins surveyed annually from 2008-2014.  A competing models analysis was used to identify local- and landscape-scale habitat characteristics to predict breeding duck pair abundance on wetland basins.  The five most commonly observed species were modeled separately; those species were mallard (Anas platyrhynchos), northern pintail (A. acuta), gadwall (A. strepera ), northern shoveler (A. clypeata) and blue-winged teal (A. discors).  At the local scale, wetland basin area, the square root transformation of wetland basin area, and wetland basin class were important predictors for all species.  Important model predictors varied by species at the landscape scale.  We applied the models in a GIS to develop a decision support tool for conservation actions funded by the Migratory Bird Conservation Fund

Changes in Nest Density and Daily Nest Survival of Two Woodpecker Species in Relation to a Mountain Pine Beetle Epidemic

The Mountain pine beetle (Dendrotonus ponderosae) is a bark beetle native to western North America capable of large-scale population eruptions, resulting in high tree (Pinus spp.) mortality that alters resource availability to wildlife, particularly snag-associated species. Many woodpecker species rely on conifer snags for nesting and foraging substrate. We studied nesting survival of two woodpecker species in relation to a recent mountain pine beetle outbreak in western Montana. American three-toed woodpecker (Picoides dorsalis) is a bark-drilling specialist that feeds on beetle larvae and frequently nests in conifer snags, whereas red-naped sapsucker (Sphyrapicus nuchalis) specializes on consuming sap of live trees and rarely nests in conifer snags. Based on a priori hypotheses we modeled daily nest survival (DSR) as a function of biotic (nest height) and temporal (beetle period [before and after outbreak], date trend, and a quadratic date trend) factors using seven competing models. Results for both species showed high model uncertainty and the constant DSR model was the most parsimonious model. These results did not support our predictions about beetle period or nest height affecting DSR, although DSR was lower during pre-outbreak (0.985, 95% CL [0.965, 0.995]) versus post-outbreak (0.993, 95% CL [0.981, 0.997]) for American three-toed woodpecker. Future analyses will investigate the effects of other covariates such as snag density, daily temperature, and precipitation on DSR. Our results will inform management activities for post-beetle forests that will help maintain habitat of disturbance specialist species