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Full-Text Articles in Population Biology

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 …


Differential Canid Predation Of Translocated Juvenile Desert Tortoises (Gopherus Agassizii) Using Chemical Signature Differences, Derek B. Hall, Bruce A. Kimball, Jennifer M. Germano, Eric M. Gese, Jeanette A. Perry Jan 2023

Differential Canid Predation Of Translocated Juvenile Desert Tortoises (Gopherus Agassizii) Using Chemical Signature Differences, Derek B. Hall, Bruce A. Kimball, Jennifer M. Germano, Eric M. Gese, Jeanette A. Perry

USDA Wildlife Services: Staff Publications

Differential predation was observed in a population of 59 translocated juvenile desert tortoises (Gopherus agassizii) of known sex during a juvenile translocation survival study between September 2012 and November 2017. The main source of mortality was attributed to coyote (Canis latrans) and kit fox (Vulpes macrotis) predation. Predation was skewed with higher female mortality than male mortality. We tested the hypothesis that juvenile females smell different than males, which leads to increased canid predation. We also explored differences in chemical signatures of resident adult female and male desert tortoises. We collected oral, cloacal, and …


Evaluating Moose Alces Alces Population Response To Infestation Level Of Winter Ticks Dermacentor Albipictus, Daniel D. Ellingwood, Peter J. Pekins, Henry Jones, Anthony R. Musante May 2020

Evaluating Moose Alces Alces Population Response To Infestation Level Of Winter Ticks Dermacentor Albipictus, Daniel D. Ellingwood, Peter J. Pekins, Henry Jones, Anthony R. Musante

USDA Wildlife Services: Staff Publications

Many wildlife populations are experiencing a variety of environmental pressures due to the direct and indirect consequences of a changing climate. In the northeast, USA, moose Alces alces are declining in large part because of the increasing parasitism by winter tick Dermacentor albipictus, facilitated by high host density and optimal environmental conditions. To test this hypothesis, and better understand the influence of this interaction on the stability of the regional population, we constructed a population viability model using data collected through comprehensive survival and productivity studies in 2002–2005 and 2014–2018 in northern New Hampshire. Years of heavy tick infestation (epizootics) …


Population Characteristics Of Co-Managed White Bass And Hybrid Striped Bass In Lake Mcconaughy, Nebraska, Benjamin J. Schall, Casey W. Schoenebeck, Keith D. Koupal Mar 2019

Population Characteristics Of Co-Managed White Bass And Hybrid Striped Bass In Lake Mcconaughy, Nebraska, Benjamin J. Schall, Casey W. Schoenebeck, Keith D. Koupal

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

White Bass (Morone chrysops) and Hybrid Striped Bass (M. saxatillis × M. chrysops) populations often coexist in the same waterbody and are known to achieve different lengths, have differing reproductive success, and provide different opportunities for anglers. However, comparative population dynamics from systems where Moronids are managed with the same regulation is often lacking. This study aimed to assess the recruitment, mortality, and growth of these species from seasonal samples collected at Lake McConaughy in 2015 and fall 2016. White Bass demonstrated highly variable recruitment in Lake McConaughy despite stocking efforts (mean recruitment variability index = …


An Update On Mortality Of Fledged Whooping Cranes In The Aransas / Wood Buffalo Population, Thomas V. Stehn, Carey L. Haralson-Strobel Jan 2016

An Update On Mortality Of Fledged Whooping Cranes In The Aransas / Wood Buffalo Population, Thomas V. Stehn, Carey L. Haralson-Strobel

Proceedings of the North American Crane Workshop

From winter 1950 through spring 2011, 6,364 whooping cranes (Grus americana) overwintered at Aransas National Wildlife Refuge, or rarely, elsewhere. Documented winter losses amounted to 105 birds dead or disappeared. About 20% of total losses occurred in the wintering area, where birds spend 5 to 6 months of the year including a few birds that over-summer. Losses of white-plumaged whooping cranes on the summering area in Canada appear to be low with only 3 instances documented. The most significant losses seem to occur in migration and may comprise over 80% of the annual mortality. Migration involves only 17-20% of the …


Thirty Years Of Mortality Assessment In Whooping Crane Reintroductions: Patterns And Implications, Barry K. Hartup, Marilyn G. Spalding, Nancy J. Thomas, Gretchen A. Cole, Young Jun Kim Jan 2010

Thirty Years Of Mortality Assessment In Whooping Crane Reintroductions: Patterns And Implications, Barry K. Hartup, Marilyn G. Spalding, Nancy J. Thomas, Gretchen A. Cole, Young Jun Kim

Proceedings of the North American Crane Workshop

We reviewed postmortem data to identify primary causes of mortality in reintroduced whooping cranes (Grus americana) and assess their potential for mitigation in future reintroduction efforts. In total, 240 cases from 3 populations were reviewed for causes of death, including the Rocky Mountain migratory population (n = 24, release dates 1975-1989), the Florida resident population (n = 186, 1993-2005), and the Wisconsin migratory population (n = 30, 2001-ongoing). Traumatic injury was the leading cause of mortality among the reintroduced whooping cranes, most commonly from predation (n = 120 or 50%, range 8-58% per project) or collision with fixed …


Causes Of Embryonic Death In Captive Whooping Cranes, Julia N. Letoutchaia, Kelly Maguire, Barry K. Hartup Jan 2010

Causes Of Embryonic Death In Captive Whooping Cranes, Julia N. Letoutchaia, Kelly Maguire, Barry K. Hartup

Proceedings of the North American Crane Workshop

In 2001, the International Whooping Crane Recovery Team and the Whooping Crane Health Advisory Team reemphasized the need for analysis of embryonic deaths within captive breeding flocks to identify preventable deaths and promote increased production of chicks for release programs. We conducted a retrospective study of egg necropsy reports to identify causes of death among developing whooping crane (Grus americana) embryos from captivity. Records from 44 egg necropsies conducted at the International Crane Foundation (ICF) between 2001 and 2008 were reviewed. The eggs were of captive origin (ICF, n = 40; Patuxent Wildlife Research Center, n = 3; …


Reproductive Health And Performance Of The Florida Flock Of Introduced Whooping Cranes, Marilyn G. Spalding, Martin J. Folk, Stephen A. Nesbitt, Richard Kiltie Jan 2010

Reproductive Health And Performance Of The Florida Flock Of Introduced Whooping Cranes, Marilyn G. Spalding, Martin J. Folk, Stephen A. Nesbitt, Richard Kiltie

Proceedings of the North American Crane Workshop

We retrospectively examined the reproductive parameters of 122 breeding-age whooping cranes (Grus americana) in a reintroduced flock in central Florida from 1992 to 2007. The flock performed poorly when compared with an existing wild flock for all reproductive parameters when controlled for age. Pairs first formed in 1995, nested in 1999, and the first chick fledged in 2002. By 2007, 19 of 63 clutches produced 25 chicks, 9 of which fledged. Drought conditions were ruled out as the sole cause of failure when the drought lessened and productivity increased, but not in all years. We examined adult health, …


A Low Intensity Sampling Method For Assessing Blue Crab Abundance At Aransas National Wildlife Refuge And Preliminary Results On The Relationship Of Blue Crab Abundance To Whooping Crane Winter Mortality, Bruce H. Pugesek, Michael J. Baldwin, Thomas V. Stehn Jan 2008

A Low Intensity Sampling Method For Assessing Blue Crab Abundance At Aransas National Wildlife Refuge And Preliminary Results On The Relationship Of Blue Crab Abundance To Whooping Crane Winter Mortality, Bruce H. Pugesek, Michael J. Baldwin, Thomas V. Stehn

Proceedings of the North American Crane Workshop

We sampled blue crabs (Callinectes sapidus) in marshes on the Aransas National Wildlife Refuge, Texas from 1997 to 2005 to determine whether whooping crane (Grus americana) mortality was related to the availability of this food source. For four years, 1997 - 2001, we sampled monthly from the fall through the spring. From these data, we developed a reduced sampling effort method that adequately characterized crab abundance and reduced the potential for disturbance to the cranes. Four additional years of data were collected with the reduced sampling effort methods. Yearly variation in crab numbers was high, ranging …


Mate Fidelity In A Dense Breeding Population Of Sandhill Cranes, Matthew A. Hayes, Jeb A. Barzen, Hugh B. Britten Jan 2008

Mate Fidelity In A Dense Breeding Population Of Sandhill Cranes, Matthew A. Hayes, Jeb A. Barzen, Hugh B. Britten

Proceedings of the North American Crane Workshop

The objective of this study was to investigate mate switches observed in a dense breeding population of banded Sandhill Cranes (Grus canadensis). Over a 14-year period, 50 of 70 breeding pairs switched mates (71%), with 45 pairs switching permanently (64%). Mean mate retention between years was 83%, with an average pair bond lasting 5.7 years (range 1-13 years). Most permanent switches occurred following the death or disappearance of a mate, and overall permanent divorce (19%; 13 of 70 pairs) and annual divorce rates (6%) were low. Territory retention following mate switches was high. Males and females did not …


Morphology, Reproduction And Mortality Of Equus Hemionus Hemionus In Mongolia, Annegret Stubbe, Michael Stubbe, Nyamsuren Batsaikhan Jan 2007

Morphology, Reproduction And Mortality Of Equus Hemionus Hemionus In Mongolia, Annegret Stubbe, Michael Stubbe, Nyamsuren Batsaikhan

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

There are collected materials on morphology, reproduction rate, and mortality of Dschiggetajs Equus h. hemionus between 2001 and 2006 in the South Gobi of Mongolia. It were found 794 skeletons of wild asses, 95% of these were pouched, ⅔ of them in winter coat. Pouching was also located in the protected areas of this region. The main living resources of Equus hemionus are registered in the South eastern Gobi. For the first time statistical data on morphology measurements of body length, tail and tuft, ear length, and hoofs are given. There are no significant differences between the sexes. The reproduction …


Sandhill Crane Mortality During Fall Migration Stopover In North-Central New Mexico, Fall 2001, William Deragon, Wendy Brown, Gail Garber, Mike Richard Jan 2005

Sandhill Crane Mortality During Fall Migration Stopover In North-Central New Mexico, Fall 2001, William Deragon, Wendy Brown, Gail Garber, Mike Richard

Proceedings of the North American Crane Workshop

Seventy-three Rocky Mountain greater sandhill cranes died after being mired in mud at a traditional migration stopover site during a fall migration 2001. Drawdown of the Jemez Canyon Dam reservoir in New Mexico resulted in over 200 acres of deep saturated silt and clay into which sandhill cranes became entrapped. Harassment to discourage birds from landing in the area was implemented immediately and partially successful. Rescue efforts were delayed because of an inability to safely access the cranes in these conditions. After 9 days, the use of a specialized 20-horsepower motor mounted on a small aluminum boat was employed. Seventeen …


Capture Of Sandhill Cranes Using Alpha-Chloralose, Matthew A. Hayes, Barry K. Hartup, Jeanne Marie Pittman, Jeb A. Barzen Jan 2005

Capture Of Sandhill Cranes Using Alpha-Chloralose, Matthew A. Hayes, Barry K. Hartup, Jeanne Marie Pittman, Jeb A. Barzen

Proceedings of the North American Crane Workshop

From 1990 – 2001, 188 captures of 166 different greater sandhill cranes (Grus canadensis tabida) were made through the experimental use of alpha-chloralose (AC) in Wisconsin (Hayes et al., 2003). Captures occurred in August (n = 28, 15%), September (n = 136, 72%) and October (n = 24, 13%). Capture of all members in the target social group was relatively high (59%). Territorial pairs were captured more successfully (2 of 2 cranes were captured 69% of the time) than family groups (3 of 3 cranes were captured 50% of the time, and 4 of 4 cranes were captured …


Evidence Of A Decline In Fat Storage By Midcontinental Sandhill Cranes In Nebraska During Spring: A Preliminary Assessment, Gary L. Krapua, David A. Brandt, Deborah A. Buhl, Gary W. Lingle Jan 2005

Evidence Of A Decline In Fat Storage By Midcontinental Sandhill Cranes In Nebraska During Spring: A Preliminary Assessment, Gary L. Krapua, David A. Brandt, Deborah A. Buhl, Gary W. Lingle

Proceedings of the North American Crane Workshop

When an ice storm killed an estimated 2,000 sandhill cranes (Grus canadensis) in the Central Platte River Valley (CPRV) in Nebraska on 24 March 1996, we retrieved the fresh carcasses of 118 adults to test for a decline in the condition of spring-staging cranes from that date in 1978 and 1979. We first conducted a principle component analysis on 3 morphological variables (tarsus, exposed culmen, and wing chord [flattened]) and used the first principal component (PC1) as an index of body size. Then, to account for variation in body mass due to size, we regressed body mass on …


First Results Of Wild Ass Research In The South Gobi Aymag/Mongolia In 2003 And 2004, Annegret Stubbe, Michael Stubbe, N. Batsajchan, R. Samjaa, S. Doržderem Jan 2005

First Results Of Wild Ass Research In The South Gobi Aymag/Mongolia In 2003 And 2004, Annegret Stubbe, Michael Stubbe, N. Batsajchan, R. Samjaa, S. Doržderem

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

The population of the Mongolian wild ass belongs to the nominate form Equus hemionus hemionus described by Pallas in 1775. This species is adapted to semidesert habitats in the Gobi region and is listed in the Red Book of Mongolia as well as on appendix I of the Washington Convention (CITES). Mapping of the northern border of the distributional range showed a remarkable decrease in size in comparison to the maps of Murzaev (1954) or Bannikov (1954). The pressure of civilization, settlements, motorization, and increasing numbers of domestic livestock in connection with the occupation of water resources and illegal hunting …


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 …


Using Ivermectin To Increase Survival Of Sandhill Crane Colts At Malheur National Wildlife Refuge, Oregon, Gary L. Ivey, Caroline P. Herziger Jan 2001

Using Ivermectin To Increase Survival Of Sandhill Crane Colts At Malheur National Wildlife Refuge, Oregon, Gary L. Ivey, Caroline P. Herziger

Proceedings of the North American Crane Workshop

Parasitic gapeworms (Cyathostoma sp.) caused 5.6% of mortalities of219 radiomarked greater sandhill crane (Grus canadensis tabida) colts at Malheur National Wildlife Refuge (NWR) in Oregon from 1991-98. From 1993-98 we tested the efficacy of ivennectin, an antihelmenthic drug, as a means of increasing colt survival by reducing gapewonn infestations. We selected pairs of siblings for the study, injecting 1 colt with ivennectin and not the other. We found significantly shorter survival times for untreated birds compared to those treated with ivennectin (P = 0.06). We conclude that in areas with gapewonn infestations in young cranes, the …


Egg Collection And Recruitment Of Young Of The Year In The Aransasi Wood Buffalo Population Of Whooping Cranes, John R. Cannon, Brian W. Johns, Thomas V. Stehn Jan 2001

Egg Collection And Recruitment Of Young Of The Year In The Aransasi Wood Buffalo Population Of Whooping Cranes, John R. Cannon, Brian W. Johns, Thomas V. Stehn

Proceedings of the North American Crane Workshop

We present data for 61 years (1938 to 1998) on the recruitment of juvenile (i.e., young-of-the-year) whooping cranes (Grus americana) for the 1 natural wild population that nests in the vicinity of Wood Buffalo National Park (WBNP) in Canada and migrates annually to wintering grounds in the vicinity of Aransas National Wildlife Refuge (ANWR) on the Gulf coast of Texas in the United States. We divide these years into 2 data sets: years during which 1 of 2 eggs was collected from WBNP nests (to develop captive populations and to conduct reintroduction experiments), and years during which no …


Interactions Of Sandhill Cranes And Whooping Cranes With Foreign Objects In Florida, Martin J. Folk, Stephen A. Nesbitt, Marilyn G. Spalding Jan 2001

Interactions Of Sandhill Cranes And Whooping Cranes With Foreign Objects In Florida, Martin J. Folk, Stephen A. Nesbitt, Marilyn G. Spalding

Proceedings of the North American Crane Workshop

During studies of Florida sandhill cranes (Grus canadensis pralensis), greater sandhill cranes (G. c. tabida), and whooping cranes (G. americana) in Florida, we documented cases where these birds were in contact with human-produced objects that resulted in injury or death. We describe >40 instances in which cranes collided with powerlines or fences, became entangled in string or fishing line, or ingested foreign objects. The effect of human-produced objects on crane populations, particularly small populations, may be significant.


Mortality Of Radio-Equipped Sandhill Crane Colts At Malheur National Wildlife Refuge, Oregon, Gary L. Ivey, Eric J. Scheuering Jan 1997

Mortality Of Radio-Equipped Sandhill Crane Colts At Malheur National Wildlife Refuge, Oregon, Gary L. Ivey, Eric J. Scheuering

Proceedings of the North American Crane Workshop

We radio-equipped 142 greater sandhill crane (Grus canadensis tabida) colts at Malheur National Wildlife Refuge, Oregon, during 1991-95 to document prefledging mortality factors. Fates of 19 colts were undetermined. A total of 23 colts survived to fledge (19% of known fates). Evidence collected from the carcasses and death sites indicated that predators were responsible for the largest number of colt deaths (64), followed by unknown causes (13), parasitic gapeworms (Cyastoma spp.) (8), drowning (7), intraspecific aggression (5), study-related mortality (I), roadkill (I), and hay swather (1). Of 64 colts killed by predators, 26 were lost to mink …


Whooping Crane Mortality At Patuxent Wildlife Research Center, 1982-95, Glenn H. Olsen, Joanna A. Taylor, George F. Gee Jan 1997

Whooping Crane Mortality At Patuxent Wildlife Research Center, 1982-95, Glenn H. Olsen, Joanna A. Taylor, George F. Gee

Proceedings of the North American Crane Workshop

Whooping cranes (Grus americana) have been reared at Patuxent Wildlife Research Center since 1966. During 1982-95 there were 103 mortalities caused by infectious and parasitic diseases (46%), trauma (21 %), anatomic abnormalities (17%), miscellaneous conditions (12 %) I and open or no diagnoses (5 %). The implications that disease may have on new whooping crane flocks in Florida and Canada are discussed, based on these mortality factors in captivity.


Causes Of Mississippi Sandhill Crane Mortality In Captivity, 1984-95, Glenn H. Olsen, George F. Gee Jan 1997

Causes Of Mississippi Sandhill Crane Mortality In Captivity, 1984-95, Glenn H. Olsen, George F. Gee

Proceedings of the North American Crane Workshop

During 1984-95, 111 deaths were documented in the captive flock of Mississippi sandhill cranes (Grus canadensis pulla) housed at the Patuxent Wildlife Research Center. Trauma was the leading cause of death (37%), followed by infectious/parasitic diseases (25%), anatomic abnormalities (15%), and miscellaneous (8%). No positive diagnosis of cause of death was found in 19% of the necropsies. Chicks < 2 months old suffered 76 % of captive deaths. Trauma, the greatest cause of deaths of captive juveniles and adults, is likely limited to collisions in the wild. Infectious/parasitic diseases and anatomic abnormalities could affect wild chick survival at similar rates to those of captive chicks.


Survival And Habitat Use Of Greater Sandhill Crane Colts On Modoc National Wildlife Refuge, California, Kevin J. Desroberts Jan 1997

Survival And Habitat Use Of Greater Sandhill Crane Colts On Modoc National Wildlife Refuge, California, Kevin J. Desroberts

Proceedings of the North American Crane Workshop

Radiotelemetry was used to monitor 13 (1990) and 14 (1992) greater sandhill crane (Grus canadensis tabida) colts on Modoc National Wildlife Refuge, California, to determine causes of mortality, brood habitat utilization, and effects of habitat management on colt survival. Colt survival rates were 0.36 (1990) and 0.54 (1992). Coyotes (Canis latrans) killed 3 colts and mink (Mustela vison) killed 4; I colt died because of a bacterial infection (Staphylococcus aureous). Broods used 6 different habitat types and 79% used more than I type. Irrigated meadows (74%), cultivated uplands (53 %), and marsh …