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

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

The Mountain Ungulate Research Initiative: A Collaborative Effort To Advance Understanding Of Bighorn Sheep And Mountain Goat Ecology

Bighorn sheep (Ovis canadensis) and mountain goats (Oreamnos americanus) are important components of the faunal assemblage of Montana’s mountainous ecosystems representing high-profile large mammals that garner substantial public interest. While population restoration, augmentation, and introductions have traditionally been the predominant conservation activities associated with these species in Montana, basic ecological research has been limited. A new research initiative has been developed and funded to study bighorn sheep and mountain goat spatial and population ecology in a number of ecological settings within the Greater Yellowstone Ecosystem. The aspiration of the collaborators is to develop a long-term research program that could expand to other populations of these species in Montana if we are successful. Primary objectives of the studies include 1) understanding the ecological interactions between sympatric populations, 2) developing and refining habitat suitability models, 3) documenting spatial dynamics within and among populations and identifying important movement corridors, 4) collecting vital rate data to better understand population dynamics, and 5) investigating potential responses of bighorn sheep and mountain goats to gradual changes in the regional climate. The presentation will describe the collaboration and ongoing efforts to consolidate all available data on bighorn sheep and mountain goats in the GYE. These data are used to describe mountain goat range expansion within the GYE over the past half century and to conduct initial habitat modeling efforts. We will also describe our plans for initiating field studies in the near future

Correlates of Recruitment in Montana Bighorn Sheep Populations: An Initiative to Synthesize Montana Bighorn Sheep Recruitment Data and Gain Biological Insight

Bighorn sheep (Ovis Canadensis) populations in Montana have been strongly affectedby disease outbreaks in recent years, resulting in the death of approximately 1500 bighorns as well as depressed recruitment rates in some affected herds. The ecology of these disease outbreaks is not well understood and there have been several proposals for a state-wide research project addressing disease ecology of bighorns in Montana. Such a project is a large investment and any extra knowledge of the bighorn populations that can be gained from existing data would improve study design and enhance the success of any future research effort. Last year we used management data to index bighorn recruitment rates of 23 bighorn herds in the Greater Yellowstone Area (GYA) and found strong correlations between recruitment and both annual and regional climate patterns. This year we have received funding from Montana Fish, Wildlife and Parks to conduct a similar analysis of bighorn recruitment rates across Montana. The planned analysis will investigate potential correlations between bighorn recruitment and climate covariates, similar to the GYA effort, but will also explore additional covariates to capture differences in management strategies, genetics, disease history, migration patterns, and population connectivity among the state’s bighorn sheep populations. The presentation will focus on the goals of our work as well as the advantages of conducting preliminary data analysis prior to implementing large scale research projects

Telemetry Studies of Mountain Ungulates in the Greater Yellowstone Area: A Progress Report

We report on the progress that has been made on initiating long-term telemetry studies of mountain goats (Oreamnos americanus) and bighorn sheep (Ovis Canadensis) in the GYA to better understand spatial ecology, demography, potential competition, and disease ecology. Six study areas representing a variety of ecological settings have been established throughout the GYA that include areas where bighorn sheep and mountain goats are sympatric as well as where each species exists in the absence of the other. We are employing a novel dual radio collar strategy and have successfully evaluated the use of drop net systems to capture groups of bighorn attracted to bait as an economical alternative to standard helicopter-based single animal capture techniques. Chemical immobilization of bighorn using BAM as an alternative to carfentanil was also tested and evaluated. A break-down Clover trap was designed for ease of transportation via horse for backcountry trapping and summer salt baiting for bighorn sheep and mountain goats was evaluated. We have initiated the first systematic disease sampling of mountain goats in the GYA using the standard protocols employed for bighorn sheep health assessments to evaluate the potential for mountain goats to influence the disease ecology of bighorn sheep in areas where they are sympatric. The research goals, strategies, and methodologies developed, tested, and employed on the collaborative GYA mountain ungulate research program are similar to those proposed for a long-term bighorn sheep research program in Montana

Breeding Season Occupancy of Long-Billed Curlews and Sandhill Cranes in Grazed Habitats at Red Rock Lakes National Wildlife Refuge, Montana

Long-billed curlew (Numenius americanus) and sandhill crane (Grus canadensis) are species of concern at state and federal levels. The concern is largely due to declines in population resulting from loss and degradation of wetland and grassland habitats that have reduced the amount of available breeding habitat for both species. Red Rock Lakes National Wildlife Refuge (RRLNWR) in southwestern Montana encompasses one of the largest wetland complexes in the Intermountain West, providing important breeding habitat for cranes and curlews in the region. We explored landscape- and plot-scale drivers of curlew and crane breeding-season occupancy (?) in grazed grassland and wet meadow habitats at RRLNWR. Distance to palustrine emergent marsh was the best landscape-scale predictor of curlew and crane occupancy. Mean breeding season occupancy of curlews across sites was 0.68 (95% CI = 0.39–0.87) and increased with distance from emergent marsh, ranging from 0.37 (95% CI = 0.24–0.52) to 0.80 (95% CI = 0.56–0.93) as distance to emergent marsh went from 64 m to 629 m. Conversely, crane mean breeding season occupancy was 0.38 (95% CI = 0.17–0.64) and decreased as distance from emergent marsh increased, ranging from 0.58 (95% CI = 0.27–0.58) to 0.28 (95% CI = 0.11–0.56) as distance to emergent marsh went from 64 m to 629 m. Plot-scale vegetation characteristics available from a reduced data set indicated curlew occupancy was positively related to the ratio of vegetation 5–15 cm tall to vegetation >15cm (??    = 4.92, SE = 2.53)

Variation in Birth Mass and Mass Gain During Lactation for a Long-Lived Mammal: A Case Study Using the Weddell Seal

Reproduction in mammals is costly, with implications for trade-offs between current reproduction and survival.  Life history theory suggests the amount of energy allocated to reproduction should change as a function of increasing maternal age, and empirical work supports both within-individual decreases (consistent with senescence) and increases (consistent with constraint and restraint).  The Weddell seal (Leptonychotes weddellii) is an ideal organism with which to study patterns of maternal energy allocation due to the life history.  Here, we used a long-term mark-recapture database of individually marked mothers and pups in Erebus Bay, Antarctica, to develop a stratified sample of masses from pups and known-age females across maternal ages in 11 different years.  Hierarchical modeling of potential sources of variation in:  1) pup masses at parturition, 2) pup mass gains from parturition to mid-lactation (~20 days), and 3) pup mass gains from mid-lactation to late-lactation (~20-days to ~35-days) was used to 1) evaluate the relative support for increases/decreases in reproductive allocation as a function of maternal age, 2) assess how patterns of reproductive allocation may reflect pre-parturition resource acquisition and/or post-parturition resource allocation, and 3) estimate the magnitude of individual heterogeneity in maternal effects after accounting for maternal and offspring characteristics. Our results provide strong evidence that reproductive investment at parturition and pup mass gains from parturition through late-lactation vary with maternal age and breeding history and result in important differences in late-lactation pup masses.   Such variation may have consequences for the early-life success of offspring, and thus implications at the population level

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

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