Digital Commons Network^™

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) …

An Historical Overview And Update Of Wolf-Moose Interactions In Northeastern Minnesota, L. David Mech, John Fieberg, Shannon M. Barber-Meyer

USGS Northern Prairie Wildlife Research Center

Wolf (Canis lupus) and moose (Alces americanus) populations in northeastern Minnesota, USA, have fluctuated for decades and, based on helicopter counts, moose numbers declined to a new low from 2006 to about 2012. Other steep declines were found in 1991 and 1998 during periods when moose counts were done with fixed-wing aircraft; these declines also appeared to be real. Winter wolf numbers, monitored in part of the moose range, had been increasing since about 2002 to the highest population in decades in 2009. However, from 2009 to 2016, wolves decreased precipitously, and the moose- population decline leveled …

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. …

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 …

White-Tailed Deer (Odocoileus Virginianus) Subsidize Gray Wolves (Canis Lupus) During A Moose (Alces Americanus) Decline: A Case Of Apparent Competition?, Shannon M. Barber-Meyer, L. David Mech

USGS Northern Prairie Wildlife Research Center

Moose (Alces americanus) in northeastern Minnesota have declined by 55% since 2006. Although the cause is unresolved, some studies have suggested that Gray Wolves (Canis lupus) contributed to the decline. After the Moose decline, wolves could either decline or switch prey. To determine which occurred in our study area, we compared winter wolf counts and summer diet before and after the Moose decline. While wolf numbers in our study area nearly doubled from 23 in winter 2002 to an average of 41 during winters 2011–2013, calf:cow ratios (the number of calves per cow observed during winter …

Patuxent’S Long-Term Research On Wolves, L. David Mech

USGS Northern Prairie Wildlife Research Center

The gray wolf (Canis lupus) was one of the first species placed on the Endangered Species List in 1967. The Endangered Species Act of 1973 legally protected the wolf along with other listed species.

Patuxent Wildlife Research Center (Patuxent) in Laurel, MD, began its Endangered Wildlife Program in 1966, and U.S. Fish and Wildlife Service (USFWS) biologist Ray Erickson was assigned to lead it. In 1973, I was transferred to the program from Region 3 of the USFWS, having been employed there since 1969 to study wolves in Minnesota.

Endangered Species Act protection of the wolf fostered its quick …

Growth Rates And Variances Of Unexploited Wolf Populations In Dynamic Equilibria, L. David Mech, John Fieberg

USGS Northern Prairie Wildlife Research Center

Several states have begun harvesting gray wolves (Canis lupus), and these states and various European countries are closely monitoring their wolf populations. To provide appropriate perspective for determining unusual or extreme fluctuations in their managed wolf populations, we analyzed natural, longterm, wolf-population-density trajectories totaling 130 years of data from 3 areas: Isle Royale National Park in Lake Superior, Michigan, USA; the east-central Superior National Forest in northeastern Minnesota, USA; and Denali National Park, Alaska, USA. Ratios between minimum and maximum annual sizes for 2 mainland populations (n = 28 and 46 yr) varied from 2.5–2.8, whereas for …

Timing Of Spring Surveys For Midcontinent Sandhill Cranes, Aaron T. Pearse, Gary L. Krapu, David A. Brandt, Glen A. Sargeant

USGS Northern Prairie Wildlife Research Center

The U.S. Fish and Wildlife Service has used spring aerial surveys to estimate numbers of migrating sandhill cranes (Grus canadensis) staging in the Platte River Valley of Nebraska, USA. Resulting estimates index the abundance of the midcontinent sandhill crane population and inform harvest management decisions. However, annual changes in the index have exceeded biologically plausible changes in population size (>50% of surveys between 1982 and 2013 indicate >20% change), raising questions about nuisance variation due to factors such as migration chronology. We used locations of cranes marked with very-highfrequency transmitters to estimate migration chronology (i.e., proportions of …

Group Composition Effects On Aggressive Interpack Interactions Of Gray Wolves In Yellowstone National Park, Kira A. Cassidy, Daniel R. Macnulty, Daniel R. Stahler, Douglas W. Smith, L. David Mech

USGS Northern Prairie Wildlife Research Center

Knowledge of characteristics that promote group success during intraspecific encounters is key to understanding the adaptive advantages of sociality for many group-living species. In addition, some individuals in a group may be more likely than others to influence intergroup conflicts, a relatively neglected idea in research on social animals. Here we use observations of aggressive interactions between wolf (Canis lupus) packs over an extended period and use pack characteristics to determine which groups had an advantage over their opponents. During 16 years of observation in Yellowstone National Park from 1995 to 2010, we documented 121 interpack aggressive interactions. We recorded …

Spring Migration Ecology Of The Mid-Continent Sandhill Crane Population With An Emphasis On Use Of The Central Platte River Valley, Nebraska, Gary L. Krapu, David A. Brandt, Paul J. Kinzel, Aaron T. Pearse

USGS Northern Prairie Wildlife Research Center

We conducted a 10-year study (1998–2007) of the Mid-Continent Population (MCP) of sandhill cranes (Grus canadensis) to identify spring-migration corridors, locations of major stopovers, and migration chronology by crane breeding affiliation (western Alaska–Siberia [WA–S], northern Canada–Nunavut [NC–N], west-central Canada–Alaska [WC–A], and east-central Canada–Minnesota [EC–M]). In the Central Platte River Valley (CPRV) of Nebraska, we evaluated factors influencing staging chronology, food habits, fat storage, and habitat use of sandhill cranes. We compared our findings to results from the Platte River Ecology Study conducted during 1978–1980. We determined spring migration corridors used by the breeding affiliations (designated subpopulations for management …

Development Of Camera Technology For Monitoring Nests, W. Andrew Cox, M. Shane Pruett, Thomas J. Benson, Scott J. Chiavacci, Frank R. Thompson Iii

USGS Northern Prairie Wildlife Research Center

Photo and video technology has become increasingly useful in the study of avian nesting ecology. However, researchers interested in using camera systems are often faced with insufficient information on the types and relative advantages of available technologies. We reviewed the literature for studies of nests that used cameras and summarized them based on study objective and the type of technology used. We also designed and tested two video systems that we used for three nest predator and behavioral studies. We found 327 studies that recorded 255 bird species spanning 19 orders. Cameras were most commonly used to study nest predators …

Spring-Migration Ecology Of Northern Pintails In South-Central Nebraska, Aaron T. Pearse, Gary L. Krapu, Robert R. Cox Jr., Bruce E. Davis

USGS Northern Prairie Wildlife Research Center

Spring-migration ecology of staging Northern Pintails, Anas acuta, was investigated in south-central Nebraska, USA. Habitat associations, local movements, settling patterns, arrival dates, residency times and survival were estimated from 71 radiomarked pintails during spring 2001, 2003 and 2004, and diet determined from 130 females collected during spring 1998 and 1999. Seventy-two percent of pintail diurnal locations were in palustrine wetlands, 7% in riverine wetlands, 3% in lacustrine wetlands, 6% in municipal sewage lagoons and irrigation reuse pits and 10.5% in croplands. Emergent wetlands with hemi-marsh conditions were used diurnally more often than wetlands with either open or closed vegetation …

Use Of Cranial Characters In Taxonomy Of The Minnesota Wolf (Canis Sp.), L. David Mech, Ronald M. Nowak, Sanford Weisberg

USGS Northern Prairie Wildlife Research Center

Minnesota wolves (Canis sp.) sometimes are reported to have affinity to a small, narrow-skulled eastern form (Canis lupus lycaon Schreber, 1775) and sometimes to a larger, broader western form (Canis lupus nubilus Say, 1823). We found that pre-1950 Minnesota wolf skulls were similar in size to those of wolves from southeastern Ontario and smaller than those of western wolves. However, Minnesota wolf skulls during 1970–1976 showed a shift to the larger, western form. Although Minnesota skull measurements after 1976 were unavailable, rostral ratios from 1969 through 1999 were consistent with hybridization between the smaller eastern wolf and …

Infectious Diseases In Yellowstone’S Canid Community, Emily S. Almberg, Paul C. Cross, L. David Mech, Doug W. Smith, Jennifer W. Sheldon, Robert L. Crabtree

USGS Northern Prairie Wildlife Research Center

Each summer Yellowstone Wolf Project staff visit den sites to monitor the success of wolf reproduction and pup rearing behavior. For the purposes of wolf monitoring, Yellowstone National Park (YNP) is divided into two study areas, the northern range and the interior, each distinguished by their ecological and physiographical differences. The 1,000 square kilometer northern range, characterized by lower elevations (1,500–2,200 m), serves as prime winter habitat for ungulates and supports a higher density of wolves than the interior (20–99 wolves/1,000 km² versus 2–11 wolves/1,000 km²). The interior of the park encompasses 7,991 square kilometers, is higher …

What Is The Taxonomic Identity Of Minnesota Wolves?, L. David Mech

USGS Northern Prairie Wildlife Research Center

The taxonomic identity of the historical and current wolf (Canis lupus L., 1758 or Canis lycaon Schreber, 1775 or their hybrids) population in Minnesota (MN) and the Great Lakes region has been, and continues to be, controversial. So too does its legal status under the U.S. Endangered Species Act. This review summarizes the morphological and genetic information about that population and concludes that historically the MN population consisted of a gray wolf (C. lupus) in the west and an eastern type (Canis lupus lycaon or C. lycaon) in the east with intergrades or hybrids between …

Chapter 2: Long-Term Research On Wolves In The Superior National Forest, L. David Mech

USGS Northern Prairie Wildlife Research Center

The seeds for the blossoming of the wolf (Canis lupus) population throughout the upper Midwest were embodied in a long line of wolves that had persisted in the central part of the Superior National Forest (SNF) of northeastern Minnesota, probably since the retreat of the last glaciers. This line of wolves had withstood not only the various natural environmental factors that had shaped them through their evolution but also the logging, fires, market hunting of prey animals, and even the bounties, aerial hunting, and poisoning that had exterminated their ancestors and their dispersed offspring only a few wolf …

Wolf Body Mass Cline Across Minnesota Related To Taxonomy?, L. David Mech, William J. Paul

USGS Northern Prairie Wildlife Research Center

Recent genetic studies suggest that in northern Minnesota two species of wolves (Canis lupus L., 1758 or western wolf and Canis lycaon Schreber, 1775 (= Canis rufus Audubon and Bachman, 1851) or eastern wolf) meet and hybridize. However, little morphological information is available about these two types of wolves in Minnesota. We analyzed the mass of 950 female wolves and 1006 males older than 1 year from across northern Minnesota and found that it increased from 26.30 ± 0.56 kg (mean ± SE) for females and 30.60 ± 0.72 kg for males in northeastern Minnesota to 30.01 ± 0.43 …

Factors Influencing Predation On Juvenile Ungulates And Natural Selection Implications, S. M. Barber-Meyer, L. D. Mech

USGS Northern Prairie Wildlife Research Center

Juvenile ungulates are generally more vulnerable to predation than are adult ungulates other than senescent individuals, not only because of their relative youth, fragility, and inexperience, but also because of congenital factors. Linnell et al.’s (Wildl. Biol. 1: 209-223) extensive review of predation on juvenile ungulates concluded that research was needed to determine the predisposition of these juveniles to predation. Since then, various characteristics that potentially predispose juvenile ungulates have emerged including blood characteristics, morphometric and other condition factors, and other factors such as birth period, the mother’s experience, and spatial and habitat aspects. To the extent that any of …

A Two-Part Measure Of Degree Of Invasion For Cross-Community Comparisons, Qinfeng Guo, Amy Symstad

USGS Northern Prairie Wildlife Research Center

Invasibility is a critical feature of ecological communities, especially for management decisions. To date, invasibility has been measured in numerous ways. Although most researchers have used the richness (or number) of exotic species as a direct or indirect measure of community invasibility, others have used alternative measures such as the survival, density, or biomass of either a single or all exotic species. These different measures, even when obtained from the same communities, have produced inconsistent results and have made comparisons among communities difficult. Here, we propose a measure of the degree of invasion (DI) of a community as a surrogate …

Femur-Marrow Fat Of White-Tailed Deer Fawns Killed By Wolves, L. David Mech

USGS Northern Prairie Wildlife Research Center

I present marrow fat (MF) data from a large sample of white-tailed deer fawns killed by wolves and a sample of fawns that died by accident in a single area, and I use these data to explore the extent that poor nutritional condition may have predisposed fawns to wolf predation. Percent MF of 110 5–10-month-old white-tailed deer (Odocoileus virginianus) fawns killed by wolves (Canis lupus) from November through April 1984–2002 in northeastern Minnesota, USA, was lower than MF for 23 fawns killed by accidents in the same area and period. The MF of both male and …

Proximate And Landscape Factors Influence Grassland Bird Distributions, Mary Ann Cunningham, Douglas H. Johnson

USGS Northern Prairie Wildlife Research Center

Ecologists increasingly recognize that birds can respond to features well beyond their normal areas of activity, but little is known about the relative importance of landscapes and proximate factors or about the scales of landscapes that influence bird distributions. We examined the influences of tree cover at both proximate and landscape scales on grassland birds, a group of birds of high conservation concern, in the Sheyenne National Grassland in North Dakota, USA. The Grassland contains a diverse array of grassland and woodland habitats. We surveyed breeding birds on 2015 100 m long transect segments during 2002 and 2003. We modeled …

Influences Of Management Regimes On Breeding Bird Densities And Habitat In Mixed-Grass Prairie: An Example From North Dakota, Andrea A. Lueders, Patricia L. Kennedy, Douglas H. Johnson

USGS Northern Prairie Wildlife Research Center

It is well known that North American grassland bird populations appear to be declining (Igl and Johnson 1997, Sauer et al. 2004). Most of these birds breed and winter in North America, so declines are likely associated with continental processes (Knopf 1994). Scientists have also observed parallel declines among species that have overlapping breeding ranges but disparate wintering distributions (Igl and Johnson 1997). These patterns suggest declines may be linked to problems on the breeding grounds.

Plains Harvest Mouse In North Dakota, Robert W. Seabloom, Terry L. Shaffer

USGS Northern Prairie Wildlife Research Center

The plains harvest mouse (Reithrodontomys montanus) is primarily a species of the central and southern plains of North America (Hall 1981, Wilkins 1986). Its published distribution extends from northwestern South Dakota south to the Mexican states of Chihuahua, Sonora, and Durango. To the west, it occurs in eastern Wyoming, Colorado, New Mexico, and southeastern Arizona, while its eastern limits are in eastern Nebraska, Kansas, Oklahoma, Texas, and southwestern Missouri. In South Dakota, R. montanus has been reported as far north as the vicinity of Ludlow, Harding County, which is the most northerly published location recorded for the species …

Bears Remain Top Summer Predators, Shannon M. Barber, L. David Mech, P. J. White

USGS Northern Prairie Wildlife Research Center

In the ten years since wolves (Canis lupus) were restored to Yellowstone National Park (YNP), elk (Cervus elaphus) numbers have substantially decreased. The northern range elk herd is the largest elk herd in Yellowstone, and constitutes the majority of the park’s elk population. During 1994–2005, early winter counts of northern Yellowstone elk decreased from 19,045 to 9,545. Also, during winters 2000–2004, calf:cow ratios declined from 29:100 to 12:100, and were among the lowest recorded during the past several decades. Though many factors (e.g., predation, hunting, and drought) likely contributed to this decreasing abundance and low recruitment, …

Brown-Headed Cowbirds In Grasslands: Their Habitats, Hosts, And Response To Management, Jill Shaffer, Christopher Goldade, Meghan Dinkins, Douglas Johnson, Lawrence Igl, Betty Euliss

USGS Northern Prairie Wildlife Research Center

The brown-headed cowbird (Molothrus ater) is an obligate brood parasite whose numbers have increased in recent decades to the potential detriment of the species that they parasitize. Thus, most management efforts focus on discouraging brown-headed cowbird parasitism or controlling brown-headed cowbird populations. Keys to discouraging cowbird parasitism or controlling populations of brown-headed cowbirds in the Great Plains are maintaining large expanses of grassland, eliminating foraging areas (e.g., feedlots) and perch sites, and reducing the extent of overgrazed pastures.

Effects Of Management Practices On Grassland Birds: American Bittern, Jill A. Dechant, Marriah L. Sondreal, Douglas H. Johnson, Lawrence D. Igl, Christopher M. Goldade, Amy L. Zimmerman, Betty R. Euliss

USGS Northern Prairie Wildlife Research Center

Information on the habitat requirements and effects of habitat management on grassland birds were summarized from information in more than 4,000 published and unpublished papers. A range map is provided to indicate the relative densities of the species in North America, based on Breeding Bird Survey (BBS) data. Although birds frequently are observed outside the breeding range indicated, the maps are intended to show areas where managers might concentrate their attention. It may be ineffectual to manage habitat at a site for a species that rarely occurs in an area. The species account begins with a brief capsule statement, which …

Less Waste Corn, More Land In Soybeans, And The Switch To Genetically Modified Crops: Trends With Important Implications For Wildlife Management, Gary L. Krapu, David A. Brandt, Robert R. Cox Jr.

USGS Northern Prairie Wildlife Research Center

American agriculture has provided abundant high-energy foods for migratory and resident wildlife populations since the onset of modern wildlife management. Responding to anecdotal evidence that corn residues are declining in cropland, we remeasured waste corn postharvest in the Central Platte River Valley (CPRV) of Nebraska during 1997 and 1998 to compare with 1978. Post-harvest waste corn averaged 2.6% and 1.8% of yield in 1997 and 1998, respectively. After accounting for a 20% increase in yield, waste corn in 1997 and 1998 was reduced 24% and 47% from 1978. We also evaluated use of soybeans by spring-staging sandhill cranes ( Grus …

Effects Of Distance From Cattle Water Developments On Grassland Birds, Andrea L. Fontaine, Patricia L. Kennedy, Douglas H. Johnson

USGS Northern Prairie Wildlife Research Center

Many North American grassland bird populations appear to be declining, which may be due to changes in grazing regimes on their breeding areas. Establishment of water developments and confining cattle (Bos taurus L.) to small pastures often minimizes spatial heterogeneity of cattle forage consumption, which may lead to uniformity in vegetative structure. This increased uniformity may provide suitable habitat for some bird species but not others. We assessed how cattle use, vegetative structure, and bird population densities varied with increasing distance from water developments (0-800 m) on the Little Missouri National Grassland (LMNG) in North Dakota. Lark buntings ( …

The Wetland Continuum: A Conceptual Framework For Interpreting Biological Studies, Ned H. Euliss Jr., James W. Labaugh, Leigh H. Fredrickson, David M. Mushet, Murray K. Laubhan, George A. Swanson, Thomas C. Winter, Donald O. Rosenberry, Richard D. Nelson

USGS Northern Prairie Wildlife Research Center

We describe a conceptual model, the wetland continuum, which allows wetland managers, scientists, and ecologists to consider simultaneously the influence of climate and hydrologic setting on wetland biological communities. Although multidimensional, the wetland continuum is most easily represented as a two-dimensional gradient, with ground water and atmospheric water constituting the horizontal and vertical axes, respectively. By locating the position of a wetland on both axes of the continuum, the potential biological expression of the wetland can be predicted at any point in time. The model provides a framework useful in the organization and interpretation of biological data from wetlands by …

Effects Of Management Practices On Grassland Birds: Northern Harrier, Jill A. Dechant, Marriah L. Sondreal, Douglas H. Johnson, Lawrence D. Igl, Christopher M. Goldade, Melvin P. Nenneman, Betty R. Euliss

USGS Northern Prairie Wildlife Research Center

Northern Harrier (Circus cyaneus):
Breeding range
Suitable habitat
Prey habitat
Area requirements
Brown-headed Cowbird brood parasitism
Breeding-season phenology and site fidelity
Species’ response to management
Management Recommendations
Habitat Characteristics