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Full-Text Articles in Life Sciences

Livestock Producers' Perceptions Of The American Black Vulture Conflict In The Midwestern United States, Marian L. Wahl, Brooke Mcwherter, Patrick A. Zollner, Zhao Ma, Grant C. Burcham, Lee A. Humberg, Brian M. Kluever Jan 2023

Livestock Producers' Perceptions Of The American Black Vulture Conflict In The Midwestern United States, Marian L. Wahl, Brooke Mcwherter, Patrick A. Zollner, Zhao Ma, Grant C. Burcham, Lee A. Humberg, Brian M. Kluever

USDA Wildlife Services: Staff Publications

Human‐wildlife interactions are present wherever both humans and wildlife are found. Interactions can be positive or negative for humans and can include impacts that range from damage to property, agriculture, health and human safety, to emotional effects. Livestock‐wildlife interactions form a major component of human‐wildlife conflicts with foci often centered on the implications of livestock predation by wildlife. While most vulture species are obligate scavengers, several species, including the American black vulture (Coragyps atratus), may attack weak or newborn livestock. Black vulture populations and distributions are expanding in the Midwestern U.S., and attacks create a novel problem for …


Predator Telemetry Informs Temporal And Spatial Overlap With Stocked Salmonids In Lake Huron, David G. Fielder, Todd A. Hayden, Thomas R. Binder, Brian S. Dorr, Heidi A. Currier Jan 2023

Predator Telemetry Informs Temporal And Spatial Overlap With Stocked Salmonids In Lake Huron, David G. Fielder, Todd A. Hayden, Thomas R. Binder, Brian S. Dorr, Heidi A. Currier

USDA Wildlife Services: Staff Publications

Double-Crested Cormorants (Phalacrocorax auratus), Walleyes (Sander vitreus), and Lake Trout (Salvelinus namaycush) are migratory predators that undergo extensive movements in Lake Huron. Stocking of juvenile salmonid fish (Oncorhynchus and Salmo sp.) is an important component of fishery management in Lake Huron and assessing the spatial and temporal extent of predator movements is a useful consideration for determining when and where to stock juvenile fish to reduce predation and maximize survival. Previous investigation indicated that some Walleyes migrate to the main basin of Lake Huron in spring from Saginaw Bay. Similarly, telemetry studies of Lake Trout movement in Lake Huron have …


Science‐Driven Guidelines Needed To Better Manage And Conserve Black Vultures In North America, Scott A. Rush, Neil J. Buckley, Patrick A. Zollner, Bryan M. Kluever, Brooke Mcwherter, Grant C. Burcham, Zhao Ma, Marian L. Wahl, Adrián Naveda‐Rodríguez Jan 2023

Science‐Driven Guidelines Needed To Better Manage And Conserve Black Vultures In North America, Scott A. Rush, Neil J. Buckley, Patrick A. Zollner, Bryan M. Kluever, Brooke Mcwherter, Grant C. Burcham, Zhao Ma, Marian L. Wahl, Adrián Naveda‐Rodríguez

USDA Wildlife Services: Staff Publications

Black vultures (Coragyps atratus) provide invaluable ecological services through disposal of carrion and the mobilization of energy within the landscape. Human‐wildlife conflicts with these birds have increased as populations have grown and the species distribution has expanded. We identify critical science needed to understand conflict between black vultures and humans to inform effective management of this species in North America. It is imperative that diagnostic criteria supporting the identification of the impacts of black vulture on livestock be standardized and verified. Management guidelines that take these criteria into account will enable reduction in the potential for black‐vulture‐farmer conflict …


Free-Ranging And Feral Cats, Alex Dutcher, Kyle Pias, Grant Sizemore, Stephen M. Vantassel Oct 2021

Free-Ranging And Feral Cats, Alex Dutcher, Kyle Pias, Grant Sizemore, Stephen M. Vantassel

Wildlife Damage Management Technical Series

Domestic cats (Felis catus) are a common household pet in the United States, with an estimated 25.4% of households owning cats (American Veterinary Medical Association 2018). While an increasing number of cat owners keep their pet cats exclusively indoors, a portion of society maintains that domestic cats are entitled to a free-ranging lifestyle and may even consider unowned domestic cats to be wildlife. Although wildlife managers recognize the beliefs of many concerned stakeholders, including advocates who use strong emotional appeals on behalf of cats, it remains that free-ranging and feral domestic cats are an invasive species spread by humans (Lowe …


Factors Influencing Survival Rates Of Pronghorn Fawns In Idaho, Brett R. Panting, Eric M. Gese, Mary M. Conner, Scott Bergen Jan 2021

Factors Influencing Survival Rates Of Pronghorn Fawns In Idaho, Brett R. Panting, Eric M. Gese, Mary M. Conner, Scott Bergen

USDA Wildlife Services: Staff Publications

Pronghorn (Antilocapra americana) occur throughout western North America. In Idaho, USA, following intensive hunting to reduce crop depredations in the late 1980s, pronghorn populations have not rebounded to desired levels. Because neonatal survival in ungulates is one factor limiting population growth, we evaluated cause‐specific mortality and the influence of intrinsic and extrinsic factors on survival rates of 217 radio‐collared pronghorn fawns across 3 study areas in Idaho during 2015–2016. For intrinsic variables, we determined the sex and body mass index (BMI) for each fawn. For extrinsic variables, we determined the abundance of predators and alternate prey, estimated the …


Economic Effects Of Predation By Scaup On Baitfish And Sportfish Farms, Carole R. Engle, Stephen Clements, Brian S. Dorr, J. Brian Davis, Luke A. Roy, Anita M. Kelly Jan 2021

Economic Effects Of Predation By Scaup On Baitfish And Sportfish Farms, Carole R. Engle, Stephen Clements, Brian S. Dorr, J. Brian Davis, Luke A. Roy, Anita M. Kelly

USDA Wildlife Services: Staff Publications

Fish-eating birds have been found to consume baitfish and sportfish raised on farms in the United States. Understanding the on-farm economic effects of such wildlife conflicts is essential for wildlife management agencies to make informed decisions. Lesser scaup, while not widely considered a fisheating bird, will consume farmed fish. Baitfish and sportfish farms in Arkansas (the major baitfish and sportfish producingstate in the U.S.) were surveyed to gather data on the cost of protecting farm crops from scaup. The values of lost sales revenue from the various species of baitfish and sportfish consumed by scaup were estimated based on a …


Conflict, Coexistence, Or Both? Cougar Habitat Selection, Prey Composition, And Mortality In A Multiple-Use Landscape, David C. Stoner, Mark A. Ditmer, Dustin L. Mitchell, Julie K. Young, Michael L. Wolfe Jan 2021

Conflict, Coexistence, Or Both? Cougar Habitat Selection, Prey Composition, And Mortality In A Multiple-Use Landscape, David C. Stoner, Mark A. Ditmer, Dustin L. Mitchell, Julie K. Young, Michael L. Wolfe

USDA Wildlife Services: Staff Publications

Western North America is experiencing remarkable human population growth and land-use change. Irrigation and associated cultivation have led to colonization of urban-wildland interface (UWI) environments by mule deer (Odocoileus hemionus), and consequently, cougars (Puma concolor). In the wake of these changes, human-wildlife conflicts have increased in tandem with questions about long-term species conservation. To address these concerns, we fit 79 cougars with radio-telemetry collars in the Oquirrh Mountains near Salt Lake City, Utah (2002–2010). Our goal was to evaluate variation in cougar habitat selection, diet, and cause-specific mortality in a landscape dominated by urban, military, and industrial activities. We used …


Coyotes, Rick Tischaefer Nov 2020

Coyotes, Rick Tischaefer

Wildlife Damage Management Technical Series

The coyote (Canis latrans; Figure 1) is a medium-sized member of the canid family. Once primarily found in western deserts and grasslands, coyotes have expanded their range across North America and into diverse habitats, including urban areas. This expansion occurred during a time of extensive habitat change and efforts by people to suppress coyote populations to prevent damage. Coyotes can cause a variety of conflicts related to agriculture, natural resources, property, and human health and safety. This document highlights a variety of methods for reducing those conflicts. Coyotes are a highly adaptable species and may become habituated to some management …


Effects Of Freshwater Crayfish On Influenza A Virus Persistence In Water, J. Jeffrey Root, Jeremy W. Ellis, Susan A. Shriner Jul 2020

Effects Of Freshwater Crayfish On Influenza A Virus Persistence In Water, J. Jeffrey Root, Jeremy W. Ellis, Susan A. Shriner

USDA Wildlife Services: Staff Publications

Several investigations have recently assessed the ability of some aquatic invertebrates to act as tools for avian influenza A virus (IAV) surveillance as well as their potential role(s) in IAV ecology. Because of this, as well as the high IAV seroprevalence rates noted in select mesocarnivores that commonly inhabit aquatic and semi-aquatic habitats, we evaluated the effects that freshwater crayfish have on IAV in water at three dose levels and monitored for the presence of IAV in crayfish tissues (gill and green gland) and haemolymph at multiple time points. At relatively high, medium 432 and low (approximately 10 , 10 …


Common Ravens, Luke W. Peebles, Jack O. Spencer Jr. Feb 2020

Common Ravens, Luke W. Peebles, Jack O. Spencer Jr.

Wildlife Damage Management Technical Series

Damage Management Methods for Common Ravens

Type of Control -- Available Management Options

Exclusion -- Often ineffective or impractical

Fertility Control -- None available

Frightening Devices -- Effigies • Pyrotechnics and propane cannons • Lasers and flashing lights

Habitat Modification -- Bale and bury garbage • Install dumpsters with secure lids • Remove or bury dead livestock • Remove abandoned houses, sheds, and barns to eliminate nesting structures

Nest Treatment -- Allowed with proper Federal and State permits; Egg oiling or addling and nest destruction

Repellents -- Methiocarb (EPA Reg. No. 56228-33) • Methyl anthranilate (food-grade grape flavoring agent)

Shooting …


An Historical Overview And Update Of Wolf-Moose Interactions In Northeastern Minnesota, L. David Mech, John Fieberg, Shannon M. Barber-Meyer Jan 2018

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 …


Where And How Wolves (Canis Lupus) Kill Beavers (Castor Canadensis), Thomas Gable, Steve K. Windels, John G. Bruggink, Austin T. Homkes Dec 2016

Where And How Wolves (Canis Lupus) Kill Beavers (Castor Canadensis), Thomas Gable, Steve K. Windels, John G. Bruggink, Austin T. Homkes

Journal Articles

Beavers (Castor canadensis) can be a significant prey item for wolves (Canis lupus) in boreal ecosystems due to their abundance and vulnerability on land. How wolves hunt beavers in these systems is largely unknown, however, because observing predation is challenging. We inferred how wolves hunt beavers by identifying kill sites using clusters of locations from GPS-collared wolves in Voyageurs National Park, Minnesota. We identified 22 sites where wolves from 4 different packs killed beavers. We classified these kill sites into 8 categories based on the beaver-habitat type near which each kill occurred. Seasonal variation existed in …


White-Tailed Deer (Odocoileus Virginianus) Fawn Risk From Gray Wolf (Canis Lupus) Predation During Summer, L. David Mech, Aaron Morris, Shannon M. Barber-Meyer Jan 2015

White-Tailed Deer (Odocoileus Virginianus) Fawn Risk From Gray Wolf (Canis Lupus) Predation During Summer, L. David Mech, Aaron Morris, Shannon M. Barber-Meyer

USGS Northern Prairie Wildlife Research Center

Little is known about how often various prey animals are at risk of predation by Gray Wolves (Canis lupus). We used a system to monitor the presence during the day of two radio-collared Gray Wolves within 2 km of a radio-collared White-tailed Deer (Odocoileus virginianus) with a fawn or fawns in August 2013 in the Superior National Forest of northeastern Minnesota. We concluded that the fawn or fawns were at risk of predation by at least one wolf at least daily.


Interference In White Bass Reproduction By Two Introduced Predators In Barren River Lake, Kentucky, Jacob Franklin Fose Dec 2013

Interference In White Bass Reproduction By Two Introduced Predators In Barren River Lake, Kentucky, Jacob Franklin Fose

Masters Theses & Specialist Projects

White bass Morone chrysops are native to the Mississippi River and its tributaries. This range includes the Barren River in south central Kentucky. Over the last thirty years, the population of white bass in Barren River Lake, a reservoir of the Barren River, has been in decline. During that same time, two congeners of white bass have been introduced to the lake. Hybrid striped bass Morone chrysops × Morone saxatilis were introduced in 1979 and yellow bass Morone mississippiensis were first discovered in 2000. Due to the similar life histories and spawning strategies of all three Morone species, I hypothesized …


Age Structure Of Moose (Alces Alces) Killed By Gray Wolves (Canis Lupus) In Northeastern Minnesota, 1967–2011, L. David Mech, Michael E. Nelson Jan 2013

Age Structure Of Moose (Alces Alces) Killed By Gray Wolves (Canis Lupus) In Northeastern Minnesota, 1967–2011, L. David Mech, Michael E. Nelson

USGS Northern Prairie Wildlife Research Center

The ages of 77 adult Moose (Alces alces) killed by gray Wolves (Canis lupus) during the period 1967–2011 in northeastern Minnesota were significantly older than those of a sample of 17 585 Moose killed by hunters in nearby Ontario. Our findings support those of earlier studies of protected Moose populations in national parks that found that gray Wolves tend to kill disproportionately more older Moose.


Nonlinear Effects Of Group Size On The Success Of Wolves Hunting Elk, Daniel R. Macnulty, Douglas W. Smith, L. David Mech, John A. Vucetich, Craig Packer Jan 2012

Nonlinear Effects Of Group Size On The Success Of Wolves Hunting Elk, Daniel R. Macnulty, Douglas W. Smith, L. David Mech, John A. Vucetich, Craig Packer

USGS Northern Prairie Wildlife Research Center

Despite the popular view that social predators live in groups because group hunting facilitates prey capture, the apparent tendency for hunting success to peak at small group sizes suggests that the formation of large groups is unrelated to prey capture. Few empirical studies, however, have tested for nonlinear relationships between hunting success and group size, and none have demonstrated why success trails off after peaking. Here, we use a unique dataset of observations of individually known wolves (Canis lupus) hunting elk (Cervus elaphus) in Yellowstone National Park to show that the relationship between success and group …


Gray Wolf (Canis Lupus) Movements And Behavior Around A Kill Site And Implications For Gps Collar Studies, L. David Mech Jan 2011

Gray Wolf (Canis Lupus) Movements And Behavior Around A Kill Site And Implications For Gps Collar Studies, L. David Mech

USGS Northern Prairie Wildlife Research Center

Global Positioning System (GPS) radio-collars are increasingly used to estimate Gray Wolf (Canis lupus) kill rates. In interpreting results from this technology, researchers make various assumptions about wolf behavior around kills, yet no detailed description of this behavior has been published. This article describes the behavior of six wolves in an area of constant daylight during 30 hours, from when the pack killed a Muskox (Ovibos moschatus) calf and yearling on Ellesmere Island, Nunavut, Canada, to when they abandoned the kill remains. Although this is only a single incident, it demonstrates one possible scenario of pack …


Problems With Studying Wolf Predation On Small Prey In Summer Via Global Positioning System Collars, Vicente Palacios, L. David Mech Jan 2011

Problems With Studying Wolf Predation On Small Prey In Summer Via Global Positioning System Collars, Vicente Palacios, L. David Mech

USGS Northern Prairie Wildlife Research Center

We attempted to study predation on various-sized prey by a male and female wolf (Canis lupus) with global positioning system (GPS) collars programmed to acquire locations every 10 min in the Superior National Forest of Minnesota. During May to August 2007, we investigated 147 clusters of locations (31% of the total) and found evidence of predation on a white-tailed deer (Odocoileus virginianus) fawn and yearling, a beaver (Castor canadensis), ruffed grouse (Bonasa umbellus), and fisher (Martes pennanti) and scavenging on a road-killed deer and other carrion. However, we missed finding …


Proportion Of Calves And Adult Muskoxen, Ovibos Moschatus Killed By Gray Wolves, Canis Lupus, In July On Ellesmere Island, L. David Mech Jan 2010

Proportion Of Calves And Adult Muskoxen, Ovibos Moschatus Killed By Gray Wolves, Canis Lupus, In July On Ellesmere Island, L. David Mech

USGS Northern Prairie Wildlife Research Center

Generally Gray Wolves (Canis lupus L., 1758) tend to focus predation on young-of-the-year ungulates during summer, and I hypothesized that wolves preying on Muskoxen (Ovibos moschatus Zimmerman, 1780) in summer would follow that trend. Over 23 July periods observing wolves on Ellesmere Island, Nunavut, Canada, I found that packs of 2-12 adult wolves killed seven calves, one yearling, and five adult muskoxen at distances of 2.9 to 32 km from their current dens and pups. Given a possible bias against finding calves because of their fewer remains, these results do not necessarily refute the hypothesis, but they do …


Estimating Predation On Declining River Herring: Tag-Recapture Study Of Striped Bass In The Connecticut River, Eric T. Schultz, Justin P. Davis, Jason Vokoun Jan 2009

Estimating Predation On Declining River Herring: Tag-Recapture Study Of Striped Bass In The Connecticut River, Eric T. Schultz, Justin P. Davis, Jason Vokoun

EEB Articles

Populations of anadromous alewife Alosa pseudoharengus and blueback herring Alosa aestivalis, collectively referred to as river herring, have declined in the Connecticut River. A hypothesis for why river herring have declined is that predation pressures have increased associated with recent increases in abundance of striped bass Morone saxatilis. Information on striped bass abundance, size structure, and consumption rates are required to test this hypothesis. This study was designed to provide estimates of striped bass population size in the Connecticut River during the spring migration season, via an intensive mark-recapture exercise and either an open or robust mark-recapture model. …


Wolf, Canis Lupus, Visits To White-Tailed Deer, Odocoileus Virginianus, Summer Ranges: Optimal Foraging?, Dominic J. Demma, L. David Mech Jan 2009

Wolf, Canis Lupus, Visits To White-Tailed Deer, Odocoileus Virginianus, Summer Ranges: Optimal Foraging?, Dominic J. Demma, L. David Mech

USGS Northern Prairie Wildlife Research Center

We tested whether Wolf (Canis lupus) visits to individual female White-tailed Deer (Odocoileus virginianus) summer ranges during 2003 and 2004 in northeastern Minnesota were in accord with optimal-foraging theory. Using GPS collars with 10- to 30-minute location attempts on four Wolves and five female deer, plus eleven VHF-collared female deer in the Wolves’ territory, provided new insights into the frequency of Wolf visits to summer ranges of female deer. Wolves made a mean 0.055 visits/day to summer ranges of deer three years and older, significantly more than their 0.032 mean visits/day to ranges of two-year-old deer, …


Factors Influencing Predation On Juvenile Ungulates And Natural Selection Implications, S. M. Barber-Meyer, L. D. Mech Jan 2008

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 …


Survival And Sources Of Mortality In Florida Sandhill Crane Chicks – Hatching To Fledging, Stephen A. Nesbitt, Stephen T. Schwikert, Marilyn G. Spalding Jan 2008

Survival And Sources Of Mortality In Florida Sandhill Crane Chicks – Hatching To Fledging, Stephen A. Nesbitt, Stephen T. Schwikert, Marilyn G. Spalding

Proceedings of the North American Crane Workshop

Forty-five pairs of Florida sandhill cranes (Grus canadensis pratensis) were monitored during the nesting seasons from 1996 through 1999. Thirty-eight chicks were produced from 25 successful nests. Twenty-one of these survived to fledging age. Predation was the source of most (81%) of the mortality for which a cause was determined. Mammals were the primary predator. Average age at time of mortality was 27.2 days for the 17 chicks lost.


Elk Calf Survival And Mortality Following Wolf Restoration To Yellowstone National Park La Supervivencia Y La Mortalidad De Las Crı´As De Wapiti Tras La Restauracio´ N Del Lobo Al Parque Nacional De Yellowstone La Survie Et La Mortalite´ Des Faons De Wapitis Qui A Suivi La Re´Introduction Du Loup Au Parc De Yellowstone, S. M. Barber-Meyer, L. David Mech, P. J. White Jan 2008

Elk Calf Survival And Mortality Following Wolf Restoration To Yellowstone National Park La Supervivencia Y La Mortalidad De Las Crı´As De Wapiti Tras La Restauracio´ N Del Lobo Al Parque Nacional De Yellowstone La Survie Et La Mortalite´ Des Faons De Wapitis Qui A Suivi La Re´Introduction Du Loup Au Parc De Yellowstone, S. M. Barber-Meyer, L. David Mech, P. J. White

USGS Northern Prairie Wildlife Research Center

We conducted a 3-year study (May 2003–Apr 2006) of mortality of northern Yellowstone elk (Cervus elaphus) calves to determine the cause for the recruitment decline (i.e., 33 calves to 13 calves/100 adult F) following the restoration of wolves (Canis lupus). We captured, fit with radiotransmitters, and evaluated blood characteristics and disease antibody seroprevalence in 151 calves ≤ 6 days old (68M:83F). Concentrations (x, SE) of potential condition indicators were as follows: thyroxine (T4; 13.8 µg/dL, 0.43), serum urea nitrogen (SUN; 17.4 mg/dL, 0.57), c-glutamyltransferase (GGT; 66.4 IU/L, 4.36), gamma globulins (GG; 1.5 g/dL, 0.07), and insulin-like …


Time Constraints Mediate Predator-Induced Plasticity In Immune Function, Condition, And Life History, Robby Stoks, Marjan De Block, Stefanie Slos, Wendy Van Doorslaer, Jens Rolff Apr 2006

Time Constraints Mediate Predator-Induced Plasticity In Immune Function, Condition, And Life History, Robby Stoks, Marjan De Block, Stefanie Slos, Wendy Van Doorslaer, Jens Rolff

Dartmouth Scholarship

The simultaneous presence of predators and a limited time for development imposes a conflict: accelerating growth under time constraints comes at the cost of higher predation risk mediated by increased foraging. The few studies that have addressed this trade-off have dealt only with life history traits such as age and size at maturity. Physiological traits have largely been ignored in studies assessing the impact of environmental stressors, and it is largely unknown whether they respond independently of life history traits. Here, we studied the simultaneous effects of time constraints, i.e., as imposed by seasonality, and predation risk on immune defense, …


Morbidity And Mortality Factors In Pre-Fledged Florida Sandhill Crane (Grus Canadensis Pratensis) Chicks, Robert J. Dusek, Marilyn G. Spalding, Donald J. Forrester, Nicholas Komar, Jonathan F. Day Jan 2005

Morbidity And Mortality Factors In Pre-Fledged Florida Sandhill Crane (Grus Canadensis Pratensis) Chicks, Robert J. Dusek, Marilyn G. Spalding, Donald J. Forrester, Nicholas Komar, Jonathan F. Day

Proceedings of the North American Crane Workshop

One hundred and fifteen Florida sandhill crane (Grus canadensis pratensis) chicks were captured in Osceola and Lake Counties, Florida in 1998 - 2000 and examined for evidence of disease. Evidence of Eimeria gruis and/or E. reichenowi infection was found in 52% of chicks examined. Ten chicks were positive for antibodies to St. Louis encephalitis virus and 1 of these chicks was also positive for antibodies to eastern equine encephalitis virus. Predation was the most commonly identified cause of mortality. An unidentified microfilaria, and an unknown protozoan were detected in blood smears from crane chicks. A number of other …


Antipredator Behavior And Physiology Determine Lestes Species Turnover Along The Pond-Permanence Gradient, Robby Stoks, Mark A. Mcpeek Dec 2003

Antipredator Behavior And Physiology Determine Lestes Species Turnover Along The Pond-Permanence Gradient, Robby Stoks, Mark A. Mcpeek

Dartmouth Scholarship

Identifying key traits that shape trade-offs that restrict species to only a subset of environmental gradients is crucial to understanding and predicting species turnover. Previous field experiments have shown that larvae of Lestes damselfly species segregate along the entire gradient of pond permanence and predator presence and that differential predation risk and life history constraints together shape their distribution. Here, we report laboratory experiments that identify key differences in behavior and physiology among species that structure their distributions along this gradient. The absence of adaptive antipredator behavioral responses against large dragonfly larvae and fish of Lestes dryas, the only species …


An Examination Of Predatory Pressures On Piping Plovers Nesting At Breezy Point, New York, Brook Lauro, John Tanacredi Ph.D. Dec 2002

An Examination Of Predatory Pressures On Piping Plovers Nesting At Breezy Point, New York, Brook Lauro, John Tanacredi Ph.D.

Faculty Works: CERCOM

This study examines predatory threats to Piping Plovers (Charadrius melodus) nesting at Breezy Point, Gateway National Recreation Area, New York. Several methods used include: 1) an evaluation of reproductive success data with documentation of predation to eggs and chicks, 2) predator surveys, and 3) an artificial nest study. The range of breeding pairs nesting from 1988-1996 was 11-19, with an average of 15.8 (SE ± 0.79) pairs/season. The average number of eggs hatched and chicks fledged per year for pairs was 2.2 ± 0.23 and 0.8 ± 0.16 respectively. Reasons for egg losses often went undetected (68%) but …


Winter Severity And Wolf Predation On A Formerly Wolf-Free Elk Herd, L. David Mech, Douglas W. Smith, Kerry M. Murphy, Daniel R. Macnulty Oct 2001

Winter Severity And Wolf Predation On A Formerly Wolf-Free Elk Herd, L. David Mech, Douglas W. Smith, Kerry M. Murphy, Daniel R. Macnulty

USGS Northern Prairie Wildlife Research Center

We studied wolf (Canis lupus) predation on elk (Cervus elaphus) in Yellowstone National Park from 17 March to 15 April 1997 (severe winter conditions) and from 2 to 31 March 1998 (mild winter conditions) 2-3 years after wolves were reintroduced to the park. Elk composed 91% of 117 kills. Data comparisons for 1997 versus 1998 were: hunting success rate, 26% versus 15%; kill rate, 17.1 kg/wolf/day versus 6.1; percent of kill consumed in first day, 7 versus 86; percent femur marrow fat of adult kills, 27 versus 70; calf:adult ratios of kills, 2:33 versus 17:23; sex …


Mortality Of Whooping Crane Colts In Wood Buffalo National Park, Canada, 1997-99, Douglas G. Bergeson, Brian W. Johns, Geoffrey L. Holroyd Jan 2001

Mortality Of Whooping Crane Colts In Wood Buffalo National Park, Canada, 1997-99, Douglas G. Bergeson, Brian W. Johns, Geoffrey L. Holroyd

Proceedings of the North American Crane Workshop

Twenty-two whooping crane (Grus americana) pairs with 2 young were monitored in Wood Buffalo National Park (WBNP) over 3 years to determine causes of colt mortality. The family groups were monitored from the ground, air, and with the aid ofradioteiemetry. We attached transmitters to 18 colts: 5 (28%) fledged, 5 (28%) succumbed to cumulative effects (head trauma, stress, exposure and/or infection), 4 (22%) were lost to unknown causes (3 of these went missing after they had lost their transmitters), 2 (11%) were taken by foxes (Vulpes vulpes), 1 (5.5%) was lost to raven (Corvus corax …