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Asymmetric Benefits Of A Heterospecific Breeding Association Vary With Habitat, Conspecific Abundance And Breeding Stage, Rose J. Swift, Michael J. Anteau, Erin A. Roche, Mark H. Sherfy, Dustin L. Toy, Megan M. Ring

USGS Northern Prairie Wildlife Research Center

Heterospecific breeding associations may benefit individuals by mitigating predation risk but may also create costs if they increase competition for resources or are more easily detectable by predators. Our understanding of the interactions among hetero- and conspecifics is often lacking in mixed species colonies. Here, we test how the presence of hetero- and conspecifics influence nest and chick survival for two listed (under the U.S. Endangered Species Act) migratory species breeding on the Missouri River, USA. We monitored 2507 piping plover Charadrius melodus nests and 3245 chicks as well as 1060 least tern Sternula antillarum nests and 1374 chicks on …

Roosting Habitat Use By Sandhill Cranes And Waterfowl On The North And South Platte Rivers In Nebraska, Dana Varner, Aaron T. Pearse, Andy Bishop, Jonas I. Davis, John C. Denton, Roger C. Grosse, Heather M. Johnson, U.S. Fish And Wildlife Service, Soldotna, Ak, Kirk D. Schroeder, Robert E. Spangler, Mark Vrtiska, Angelina E. Wright

USGS Northern Prairie Wildlife Research Center

Migration ecology and habitat use of spring migrating birds using the Central Platte River is a well-explored topic, yet less is known about use of the North and South Platte rivers (NSPR) in western Nebraska. The efficiency and effectiveness of conservation efforts in the NSPR could be greatly improved with access to information about where and when birds roost and landscape prioritization tools. We used aerial surveys to determine population distribution and migration phenology of sandhill cranes Antigone canadensis, Canada geese Branta canadensis, and ducks using the NSPR for roosting during the mid-February to mid-April spring migration. We used these …

Population And Harvest Dynamics Of Midcontinent Sandhill Cranes, Aaron T. Pearse, Glen A. Sargeant, Gary L. Krapu, David A. Brandt

USGS Northern Prairie Wildlife Research Center

Sandhill cranes (Antigone canadensis) inhabiting the midcontinent of North America have been hunted since the 1960s under management goals of maintaining abundance, retaining geographic distribution, and maximizing sustainable harvest. Some biologists have raised concerns regarding harvest sustainability because sandhill cranes have lower reproductive rates than other game birds. We summarized demographic information in an age‐structured matrix model to better understand population dynamics and harvest. Population indices and recovered harvest since the early 1980s suggest midcontinent sandhill cranes have experienced an average long‐term annual growth of 0.9%; meanwhile, harvest has increased 1.8% annually. Adult survival and recruitment rates estimated from field …

Temporospatial Shifts In Sandhill Crane Staging In The Central Platte River Valley In Response To Climatic Variation And Habitat Change, Andrew J. Caven, Emma M. Brinley Buckley, Kelsey C. King, Joshua Wiese, David M. Baasch, Greg D. Wright, Mary Harner, Aaron T. Pearse, Matt Raabe, Dana Varner, Brice Krohn, Nicole Arcilla, Kirk D. Schroeder, Kenneth F. Dinan

USGS Northern Prairie Wildlife Research Center

Over 80% of the Mid-Continent Sandhill Crane (Antigone canadensis) Population (MCP), estimated at over 660,000 individuals, stops in the Central Platte River Valley (CPRV) during spring migration from mid-February through mid-April. Research suggests that the MCP may be shifting its distribution spatially and temporally within the CPRV. From 2002 to 2017, we conducted weekly aerial surveys of Sandhill Cranes staging in the CPRV to examine temporal and spatial trends in their abundance and distribution. Then, we used winter temperature and drought severity measures from key wintering and early migratory stopover locations to assess the impacts of weather patterns …

Energy Development And Production In The Great Plains: Implications And Mitigation Opportunities, Jacqueline P. Ott, Bruce B. Hanberry, Mona Khalil, Mark W. Paschke, Max Post Van Der Burg, A.J. Prenni

USGS Northern Prairie Wildlife Research Center

Energy is an integral part of society. The major US energy sources of fossil fuels (coal, oil, natural gas); biofuels (ethanol); and wind are concentrated in grassland ecosystems of the Great Plains. As energy de- mand continues to increase, mounting pressures will be placed on North American grassland systems. In this review, we present the ecological effects of energy development and production on grassland sys- tems. We then identify opportunities to mitigate these effects during the planning, construction, and pro- duction phases by using informed methodology and improved technology. Primary effects during energy development include small- and large-scale soil disturbance …

Estimating Offsets For Avian Displacement Effects Of Anthropogenic Impacts, Jiill A. Shaffer, Charles R. Loesch, Deborah A. Buhl

USGS Northern Prairie Wildlife Research Center

Biodiversity offsetting, or compensatory mitigation, is increasingly being used in temperate grassland ecosystems to compensate for unavoidable environmental damage from anthropogenic developments such as transportation infrastructure, urbanization, and energy development. Pursuit of energy independence in the United States will expand domestic energy production. Concurrent with this increased growth is increased disruption to wildlife habitats, including avian displacement from suitable breeding habitat. Recent studies at energy-extraction and energy-generation facilities have provided evidence for behavioral avoidance and thus reduced use of habitat by breeding waterfowl and grassland birds in the vicinity of energy infrastructure. To quantify and compensate for this loss in …

Emerging Themes From The Esa Symposium Entitled “Pollinator Nutrition: Lessons From Bees At Individual To Landscape Levels”, Vanessa Corby-Harris, Julia H. Bowsher, Morgan Carr-Markell, Mark J. Carroll, Mary Centrella, Steven C. Cook, Margaret Couvillon, Gloria Degrandi-Hoffman, Adam Dolezal, Julia C. Jones, Christina L. Mogren, Clint R. V. Otto, Pierre Lau, Juliana Rangel, Roger Schürch, Ashley St. Clair

USGS Northern Prairie Wildlife Research Center

Pollinator populations are declining (Biesmeijer et al., 2006; Brodschneider et al., 2018; Cameron et al., 2011; Goulson, Lye, & Darvill, 2008; Kulhanek et al., 2017; National Research Council, 2007; Oldroyd, 2007), and both anecdotal and experimental evidence suggest that limited access to high quality forage might play a role (Carvell, Meek, Pywell, Goulson, & Nowakowski, 2007; Deepa et al., 2017; Goulson, Nicholls, Botias, & Rotheray, 2015; Potts et al., 2003, 2010; Vanbergen & The Insect Pollinators Initiative, 2013; Vaudo, Tooker, Grozinger, & Patch, 2015; Woodard, 2017). Multiple researchers are earnestly addressing this topic in a diverse array of insect-pollinator systems. …

Effects Of Land Use On Greenhouse Gas Flux In Playa Wetlands And Associated Watersheds In The High Plains, Usa, Dale W. Daniel, Loren M. Smith, Scott T. Mcmurry, Brian A. Tangen, Charles F. Dahl, Ned H. Euliss Jr., Ted Lagrange

USGS Northern Prairie Wildlife Research Center

In the High Plains, U.S., native prairie conversion to cropland agriculture has resulted in a loss of service delivery capabilities from most depressional wet-lands as a result of sedimentation. Restoring historic hydrological conditions to affected wetlands may rejuvenate some services, however, there may be tradeoffs due to emissions of CH4 and N2O. We evaluated the influence of two predominant conservation programs (Wetlands Reserve Program, WRP and Conservation Reserve Program, CRP) on gas emissions (CO2, CH4, N2O) from 42 playas and uplands in the High Plains of Nebraska. Because playa restoration through the WRP is most prevalent in the Rainwater Basin …

Whooping Crane Use Of Riverine Stopover Sites, David M. Baasch, Patrick D. Farrell, Shay Howlin, Aaron T. Pearse, Jason M. Farnsworth, Chadwin B. Smith

USGS Northern Prairie Wildlife Research Center

Migratory birds like endangered whooping cranes (Grus americana) require suitable nocturnal roost sites during twice annual migrations. Whooping cranes primarily roost in shallow surface water wetlands, ponds, and rivers. All these features have been greatly impacted by human activities, which present threats to the continued recovery of the species. A portion of one such river, the central Platte River, has been identified as critical habitat for the survival of the endangered whooping crane. Management intervention is now underway to rehabilitate habitat form and function on the central Platte River to increase use and thereby contribute to the survival of whooping …

Modeling Effects Of Crop Production, Energy Development And Conservation-Grassland Loss On Avian Habitat, Jiill A. Shaffer, Cali L. Roth, David M. Mushet

USGS Northern Prairie Wildlife Research Center

Birds are essential components of most ecosystems and provide many services valued by society. However, many populations have undergone striking declines as their habitats have been lost or degraded by human activities. Terrestrial grasslands are vital habitat for birds in the North American Prairie Pothole Region (PPR), but grassland conversion and fragmentation from agriculture and energy-production activities have destroyed or degraded millions of hectares. Conservation grasslands can provide alternate habitat. In the United States, the Conservation Reserve Program (CRP) is the largest program maintaining conservation grasslands on agricultural lands, but conservation grasslands in the PPR have declined by over 1 …

Revisiting The Historic Distribution And Habitats Of The Whooping Crane, Jane E. Austin, Matthew A. Hayes, Jeb A. Barzen

USGS Northern Prairie Wildlife Research Center

Understanding the historic range and habitats of an endangered species can assist in conservation and reintroduction efforts for that species. Individuals reintroduced into a species’ historic core range have a higher survival rate compared to individuals introduced near the periphery or outside the historic range (Falk and Olwell, 1992; Griffith et al., 1989). Individuals on the periphery of a species’ range tend to occupy less favorable habitats and have lower and more variable densities than those near the core of their range (Brown, 1984; Brown et al., 1995, 1996). Such conclusions, however, presume that historic habitats have not changed since …

U.S. Geological Survey- Northern Prairie Wildlife Research Center 2017 Research Activity Report, Mark H. Sherfy

USGS Northern Prairie Wildlife Research Center

Contents

Acknowledgments...............................................................................iii

Center Mission and Science Strategy...............................................................1

Lines of Work..................................................................................2

Study Narratives.................................................................................16

Diurnal Habitat Selection Of Migrating Whooping Crane In The Great Plains, David M. Baasch, Patrick D. Farrell, Aaron T. Pearse, David A. Brandt, Andrew J. Caven, Mary J. Harner, Greg D. Wright, Kristine L. Metzger

USGS Northern Prairie Wildlife Research Center

Available stopover habitats with quality foraging opportunities are essential for migrating waterbirds, including Whooping Crane (Grus americana). Several studies have evaluated habitats used by Whooping Crane for roosting throughout its migration corridor; however, habitats associated with foraging and other diurnal activities have received less attention. We used data collected from 42 Whooping Crane individuals that included 2169 diurnal use locations within 395 stopover sites evaluated during spring 2013 to fall 2015 to assess diurnal habitat selection throughout the U.S. portion of the migration corridor. We found that Whooping Crane selected wetland land-cover types (i.e., open water, riverine, and semipermanent wetlands) …

Mortality In Aransas-Wood Buffalo Whooping Cranes: Timing, Location, And Causes, Aaron T. Pearse, David A. Brandt, Barry K. Hartup, Mark T. Bidwell

USGS Northern Prairie Wildlife Research Center

The Aransas-Wood Buffalo Population (AWBP) of Whooping Cranes (Grus americana) has experienced a population growth rate of approximately 4% for multiple decades (Butler et al., 2014a; Miller et al., 1974). Population growth for long-lived species of birds is generally highly sensitive to variation in adult mortality rates (Sæther and Bakke, 2000). A population model for endangered Red-crowned Cranes (Grus japonensis) in Japan conforms to this pattern, where growth rate is most sensitive to adult mortality (Masatomi et al., 2007). Earlier analyses observed that the AWBP growth rate increased in the mid-1950s and that this increase was likely caused by reduced …

Implications Of Spatially Variable Costs And Habitat Conversion Risk In Landscape-Scale Conservation Planning, Max Post Van Der Burg, Neil Chartier, Ryan Drum

USGS Northern Prairie Wildlife Research Center

‘‘Strategic habitat conservation’’ refers to a process used by the U.S. Fish and Wildlife Service to develop cost-efficient strategies for conserving wildlife populations and their habitats. Strategic habitat conservation focuses on resolving uncertainties surrounding habitat conservation to meet specific wildlife population objectives (i.e., targets) and developing tools to guide where conservation actions should be focused on the landscape. Although there are examples of using optimization models to highlight where conservation should be delivered, such methods often do not explicitly account for spatial variation in the costs of conservation actions. Furthermore, many planning approaches assume that habitat protection is a preferred …

Prairie Reconstruction Unpredictability And Complexity: What Is The Rate Of Reconstruction Failures?, Jack E. Norland, Cami Dixon, Diane Larson, Kristine Askerooth, Benjamin A. Geaumont

USGS Northern Prairie Wildlife Research Center

The outcomes of prairie reconstructions are subject to both unpredictability and complexity. Prairie, tallgrass, and mixed grass reconstruction is defined as the planting of a native herbaceous seed mixture composed of multiple prairie species (10 or more) in an area where the land has been heavily cultivated or anthropogenically disturbed. Because of the unpredictability and complexity inherent in reconstructions, some outcomes end up being failures dominated by exotic species. We propose that these failures follow a fat-tailed distribution as found in other complex systems. Fat-tailed distributions follow the Pareto principle, where 80% of the time reconstructions work as expected but …

13 Terrestrial Wetlands, Randall Kolka, Carl T Trettin

USGS Northern Prairie Wildlife Research Center

The objective of this chapter is to characterize the distribution of carbon stocks and fluxes in terrestrial wetlands within North America. The approach was to synthesize available literature from field measurements with analyses of resource inventory data to estimate wetland area, carbon stocks, and net ecosystem exchange (NEE) of carbon and methane (CH4) fluxes of terrestrial wetlands (see Appendices 13A, p. 547, and 13B, p. 557, for details1). Then, the findings employed from large-scale simulation studies provided additional context, with consideration given to the effects of disturbance regimes, restoration and creation of terrestrial wetlands, and the application of modeling tools …

Landscape Genetics Reveal Broad And Fine‐Scale Population Structure Due To Landscape Features And Climate History In The Northern Leopard Frog (Rana Pipiens) In North Dakota, Justin M. Waraniak, Justin D. L. Fisher, Kevin Purcell, David M. Mushet, Craig A. Stockwell

USGS Northern Prairie Wildlife Research Center

Prehistoric climate and landscape features play large roles structuring wildlife populations. The amphibians of the northern Great Plains of North America present an opportunity to investigate how these factors affect colonization, migration, and current population genetic structure. This study used 11 microsatellite loci to genotype 1,230 northern leopard frogs (Rana pipiens) from 41 wetlands (30 samples/wetland) across North Dakota. Genetic structure of the sampled frogs was evaluated using Bayesian and multivariate clustering methods. All analyses produced concordant results, identifying a major east–west split between two R. pipiens population clusters separated by the Missouri River. Substructuring within the two major identified …

Landscape Genetics Reveal Broad And Fine‐Scale Population Structure Due To Landscape Features And Climate History In The Northern Leopard Frog (Rana Pipiens) In North Dakota, Justin M. Waraniak, Justin D.L. Fisher, Kevin Purcell, David M. Mushet, Craig A. Stockwell

USGS Northern Prairie Wildlife Research Center

Prehistoric climate and landscape features play large roles structuring wildlife populations. The amphibians of the northern Great Plains of North America present an opportunity to investigate how these factors affect colonization, migration, and current population genetic structure. This study used 11 microsatellite loci to genotype 1,230 northern leopard frogs (Rana pipiens) from 41 wetlands (30 samples/wetland) across North Dakota. Genetic structure of the sampled frogs was evaluated using Bayesian and multivariate clustering methods. All analyses produced concordant results, identifying a major east–west split between two R. pipiens population clusters separated by the Missouri River. Substructuring within the two major identified …

Multi-Element Fingerprinting Of Waters To Evaluate Connectivity Among Depressional Wetlands, Yuxiang Yuan, Xiaoyan Zhu, David M. Mushet, Marinus L. Otte

USGS Northern Prairie Wildlife Research Center

Establishing the connectivity among depressional wetlands is important for their proper management, conservation and restoration. In this study, the concentrations of 38 elements in surface water and porewater of depressional wetlands were investigated to determine chemical and hydrological connectivity of three hydrological types: recharge, flow-through, and discharge, in the Prairie Pothole Region of North America. Most element concentrations of porewater varied significantly by wetland hydrologic type (p < 0.05), and increased along a recharge to discharge hydrologic gradient. Significant spatial variation of element concentrations in surface water was observed in discharge wetlands. Generally, higher element concentrations occurred in natural wetlands compared to wetlands with known disturbances (previous drainage and grazing). Electrical conductivity explained 42.3% and 30.5% of the variation of all element concentrations in porewater and surface water. Non-metric multidimensional scaling analysis showed that the similarity decreased from recharge to flowthrough to discharge wetland in each sampling site. Cluster analysis confirmed that element compositions in porewater of interconnected wetlands were more similar to each other than to those of wetlands located farther away. Porewater and surface water in a restored wetland showed similar multi-element characteristics to natural wetlands. In contrast, depressional wetlands connected by seeps along a deactivated drain-tile path and a grazed wetland showed distinctly different multi-element characteristics compared to other wetlands sampled. Our findings confirm that the multi-element fingerprinting method can be useful for assessing hydro-chemical connectivity across the landscape, and indicate that element concentrations are not only affected by land use, but also by hydrological characteristics.

The Usefulness Of Gps Telemetry To Study Wolf Circadian And Social Activity, Samuel B. Merrill, L. David Mech

USGS Northern Prairie Wildlife Research Center

This study describes circadian and social movement patterns of 9 wolves and illustrates capabilities and limitations of Global Positioning System (GPS) telemetry for analysis of animal activity patterns. Wolves were studied at the Camp Ripley National Guard Training Site in Little Falls, Minnesota, and were captured via helicopter net-gunning. All study wolves showed nocturnal movement patterns regardless of time of year. One wolf's movement pattern switched to diurnal when he conducted an extraterritorial foray from his natal territory. All data sets with GPS intervals <1 hour (n=4) showed crepuscular movement peaks. We identified patterns of den visitation and attendance, estimated minimum distances traveled and minimum rates of movement, and observed that GPS location intervals may affect perceived rates of wolf travel. Global Positioning System telemetry was useful in determining when pack members were traveling together or apart and how long a breeding female wolf spent near her pups (e.g., 0-month-old pups were left unattended by their mother for as long as 17 days).

Bird Population Changes Following The Establishment Of A Diverse Stand Of Woody Plants In A Former Crop Field In North Dakota, 1975– 2015, Lawrence D. Igl, Harold A. Kantrud, Wesley Newton

USGS Northern Prairie Wildlife Research Center

Changes in the coverage of trees and shrubs on the North Dakota landscape since Euro- American settlement have likely had a pronounced impact on bird species that favor woody vegetation. Long- term data sets on breeding bird populations in wooded habitats in North Dakota or in the Great Plains are scarce. In 1975 a wildlife habitat plot was established in a 10.5 ha cropland field with a long history of small- grain production. Th e objective of this article is to evaluate the successional changes in bird populations as the habitat at this site became more biologically and structurally complex …

Conserving All The Pollinators: Variation In Probability Of Pollen Transport Among Insect Taxa, Diane L. Larson, Jennifer L. Larson, Deborah A. Buhl

USGS Northern Prairie Wildlife Research Center

As concern about declining pollinator populations mounts, it is important to understand the range of insect taxa that provide pollination services. We use pollen transport information acquired over three years in two habitats at Badlands National Park, South Dakota, USA, to compare probabilities of pollen transport among insect taxa and between sexes of bees. Sampling was conducted on 1-ha plots, eight in sparse vegetation (May–October samples; N = 74 surveys) and 12 in wheatgrass prairie vegetation (June–July samples; N = 87 surveys). Insects contacting reproductive parts of flowers were netted, placed individually into tubes charged with ethyl acetate, then transferred …

Distance Models As A Tool For Modelling Detection Probability And Density Of Native Bumblebees, Darin J. Mcneil, Clint R. V. Otto, Erin L. Moser, Katherine R. Urban‐Mead, David E. King, Amanda D. Rodewald, Jeffery L. Larkin

USGS Northern Prairie Wildlife Research Center

Effective monitoring of native bee populations requires accurate estimates of population size and relative abundance among habitats. Current bee survey methods, such as netting or pan trapping, may be adequate for a variety of study objectives but are limited by a failure to account for imperfect detection. Biases due to imperfect detection could result in inaccurate abundance estimates or erroneous insights about the response of bees to different environments. To gauge the potential biases of currently employed survey methods, we compared abundance estimates of bumblebees (Bombus spp.) derived from hierarchical distance sampling models (HDS) to bumblebee counts collected from fixed‐area …

Understanding And Finding Solutions To The Problem Of Sedimentation In The National Wildlife Refuge System, Max Post Van Der Burg, Karen E. Jenni, Timothy L. Nieman, Josh D. Eash, Gregory A. Knutsen

USGS Northern Prairie Wildlife Research Center

The National Wildlife Refuge System (Refuge System) is a collection of public lands maintained by the U.S. Fish and Wildlife Service for migratory birds and other wildlife. Wetlands on individual National Wildlife Refuges (Refuges) may be at risk of increased sedimentation because of land use and water management practices. Increased sedimentation can reduce wetland habitat quality by altering hydrologic function, degrading water quality, and inhibiting growth of vegetation and invertebrates. On Refuges negatively affected by increased sedimentation, managers have to address complex questions about how to best remediate and mitigate the negative effects. The best way to account for these …

An Unparalleled Opportunity For An Important Ecological Study, L. David Mech, Shannon M. Barber-Meyer, Juan Carlos Blanco, Luigi Boitani, Ludwig Carbyn, Glenn Delgiudice, Steven H. Fritts, Djuro Huber, Olof Liberg, Brent Patterson, Richard R. Thiel

USGS Northern Prairie Wildlife Research Center

Wolves (Canis lupus) and moose (Alces americanus) have been studied since 1958 on 540-squarekilometer Isle Royale National Park, in Lake Superior. Wolves arrived there across the ice around 1949, and the population once increased to about 50, averaging about 25 annually (Mech 1966, Jordan et al. 1967, Vucetich and Peterson 2009). However, for various reasons, wolf numbers there have now dwindled to 2 nonbreeders, and the US National Park Service has proposed reintroducing 20–30 wolves over 3 years (National Park Service 2016). This situation offers an unparalleled opportunity to promote science-based management of this unique national park. …

A Serosurvey Of Diseases Of Free-Ranging Gray Wolves (Canis Lupus) In Minnesota, Usa, Michelle Carstensen, John H. Giudice, Erik C. Hildebrand, J. P. Dubey, John Erb, Dan Stark, John Hart, Shannon M. Barber-Meyer, L. David Mech, Steve K. Windels, Andrew J. Edwards

USGS Northern Prairie Wildlife Research Center

We tested serum samples from 387 free-ranging wolves (Canis lupus) from 2007 to 2013 for exposure to eight canid pathogens to establish baseline data on disease prevalence and spatial distribution in Minnesota’s wolf population. We found high exposure to canine adenoviruses 1 and 2 (88% adults, 45% pups), canine parvovirus (82% adults, 24% pups), and Lyme disease (76% adults, 39% pups). Sixty-six percent of adults and 36% of pups exhibited exposure to the protozoan parasite Neospora caninum. Exposure to arboviruses was confirmed, including West Nile virus (37% adults, 18% pups) and eastern equine encephalitis (3% adults). Exposure rates …

Where Can Wolves Live And How Can We Live With Them?, L. David Mech

USGS Northern Prairie Wildlife Research Center

In the contiguous 48 United States, southern Canada, and in Europe, wolves (Canis lupus) have greatly increased and expanded their range during the past few decades.They are prolific, disperse long distances, readily recolonize new areas where humans allow them, and are difficult to control when populations become established.Because wolves originally lived nearly everywhere throughout North America and Eurasia, and food in the form of wild and domestic prey is abundant there, many conservation-minded people favor wolves inhabiting even more areas.On the other hand, wolves conflict in several ways with rural residents who prefer fewer wolves. This article discusses …

Sandhill Crane Roost Selection, Human Disturbance, And Forage Resources, Aaron T. Pearse, Gary L. Krapu, David A. Brandt

USGS Northern Prairie Wildlife Research Center

Sites used for roosting represent a key habitat requirement for many species of birds because availability and quality of roost sites can influence individual fitness. Birds select roost sites based on numerous factors, requirements, and motivations, and selection of roosts can be dynamic in time and space because of various ecological and environmental influences. For sandhill cranes (Antigone canadensis) at their main spring staging area along the Platte River in south-central Nebraska, USA, past investigations of roosting cranes focuse donphysical channel characteristics related to perceived security as motivating roost distribution.We used 6,310 roost sites selected by 313 sandhill cranes over …

Differential Wolf-Pack-Size Persistence And The Role Of Risk When Hunting Dangerous Prey, Shannon M. Barber-Meyer, L. David Mech, Wesley E. Newton, Bridget L. Borg

USGS Northern Prairie Wildlife Research Center

Risk to predators hunting dangerous prey is an emerging area of research and could account for possible persistent differences in gray wolf (Canis lupus) pack sizes. We documented significant differences in long-term wolf-pack-size averages and variation in the Superior National Forest (SNF), Denali National Park and Preserve, Yellowstone National Park, and Yukon, Canada (p < 0.01). The SNF differences could be related to the wolves’ risk when hunting primary prey, for those packs (N = 3) hunting moose (Alces americanus) were significantly larger than those (N = 10) hunting white-tailed deer (Odocoileus virginianus) (F1,8 = 16.50, p = 0.004). Our data support the hypothesis that differential pack-size persistence may be perpetuated by differences in primary prey riskiness to …