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Behavior and Ethology

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Articles 331 - 360 of 564

Full-Text Articles in Ornithology

Fecal Corticoid Monitoring In Whooping Cranes Trained To Follow Ultralight Aircraft, Barry K. Hartup, Nancy M. Czekala, Glenn H. Olsen, Julia A. Langenberg Jan 2005

Fecal Corticoid Monitoring In Whooping Cranes Trained To Follow Ultralight Aircraft, Barry K. Hartup, Nancy M. Czekala, Glenn H. Olsen, Julia A. Langenberg

Proceedings of the North American Crane Workshop

The use of fecal corticoid assays to measure stress in North American cranes has been limited to laboratory validation and a single field project involving reintroduced sandhill cranes (Ludders et al., 1998, 2001; Hartup et al., 2004). In 2001, we documented trends in corticoid concentrations among a cohort of ten costume-reared whooping cranes subjected to ultralight aircraft training and migration. All samples were analyzed by a validated corticosterone 125I radioimmunoassay for determination of corticoid levels. Fecal corticoid concentrations in chicks exhibited a logarithmic decline over the first 14 days after hatching (r = 0.86, p < 0.001). Fecal corticoid concentrations then stabilized at baseline levels (median 68 ng/g, range 17–186 ng/g, n = 116) during the subsequent six weeks of costume-rearing and aircraft habituation in captivity. Fecal corticoid concentrations of eight cranes increased 8-34 fold during shipment in crates to Wisconsin for field training. Increases in fecal corticoid concentrations were positively correlated with age (r = 0.81, p = 0.01), but not body weight (r = 0.44, p = 0.28) at the time of shipping. Fecal corticoid concentrations returned to baseline levels within seven days, and were sustained throughout the remainder of the training period (median 77 ng/g, range 22– 292 ng/g, n=190). Elevations in fecal corticoid concentrations were observed one (p = 0.035) and four days (p = 0.003) following physical examination and placement of leg bands compared to three days prior to the procedures (median 176 ng/g, range 116 – 553 ng/g, n = 19). Fecal corticoid concentrations decreased to pre-procedure levels within seven days. Fecal corticoid concentrations and variation during the 50 day migration period were similar to training levels in Wisconsin, except for a one day increase observed following a violent storm and escape from the temporary holding pen the preceding night (median 243 ng/g, range 228 – 280 ng/g, n = 7). There was an overall decline in fecal corticoid concentrations from the cranes during the migration (r = 0.42, p < 0.001). Acute stressors such as capture and restraint and severe storms were associated with stress responses by the cranes that varied in accordance with lasting physical or psychological stimuli. The overall process of costume-rearing, ultralight aircraft habituation, training and artificial migration was not associated with elevations in fecal corticoid concentrations suggestive of chronic stress.

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New Locations And Range Extension Of Wintering Sandhill Cranes In Central Northern Mexico, Felipe Chavez-Ramirez Jan 2005

New Locations And Range Extension Of Wintering Sandhill Cranes In Central Northern Mexico, Felipe Chavez-Ramirez

Proceedings of the North American Crane Workshop

The overall distribution of wintering sandhill cranes in Mexico has been reported and summarized in several prior documents. However, most reports are associated with counts or surveys primarily conducted for wintering waterfowl. Recent (1999- 2002) reports compiled from local researchers show, that wintering sandhill cranes are distributed much more widely in northern Mexico than is currently reported in the literature. The new locations reported here are primarily in the eastern portion of the Mexican Altiplano, in the states of Coahuila and Nuevo Leon, and in the southern portions of the Chihuahuan Desert Region in Zacatecas and San Luis Potosi. Most …

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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 …

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Patterns Of Habitat Use By Whooping Cranes During Migration: Summary From 1977–1999 Site Evaluation Data, Jane E. Austin, Amy L. Richert Jan 2005

Patterns Of Habitat Use By Whooping Cranes During Migration: Summary From 1977–1999 Site Evaluation Data, Jane E. Austin, Amy L. Richert

Proceedings of the North American Crane Workshop

We used site evaluation data collected during 1977–1999 to examine patterns of habitat use by whooping cranes (Grus americana) during migration through the United States portion of the Wood Buffalo–Aransas flyway. We examined characteristics of 3 types of stopover habitats: 1) roost sites (n = 141 records), 2) feeding sites (n = 306), and 3) dual-use sites (i.e., where observer recorded cranes as using a site for both roosting and feeding (n = 248). Results in spring were influenced by the large number of records from Nebraska (> 67% of spring records) and in fall by frequent observations …

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Philopatry And Dispersal In Whooping Cranes, Brian W. Johns, J. Paul Goossen, Ernie Kuyt, Lea Craig-Moore Jan 2005

Philopatry And Dispersal In Whooping Cranes, Brian W. Johns, J. Paul Goossen, Ernie Kuyt, Lea Craig-Moore

Proceedings of the North American Crane Workshop

The natal and breeding dispersal of endangered whooping cranes (Grus americana) was investigated using information collected between 1978-2002 on the nesting grounds in and near Wood Buffalo National Park, Alberta-Northwest Territories. A minimum of 77% of the juveniles color-banded near their natal sites returned to the breeding grounds. Sex-biased natal dispersal was not observed. At least 76% of first-time breeders nested within 20 km of their natal site. Pioneering was rare and most cranes nested on the primary nesting areas adjacent to the Sass and Klewi rivers. The mechanism enhancing natal philopatry is probably related to learning the …

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Techniques Employed To Capture Whooping Cranes In Central Florida, Martin J. Folk, Stephen A. Nesbitt, Stephen T. Schwikert, James A. Schmidt, Kathleen A. Sullivan, Thomas J. Miller, Stephen B. Baynes, Jeannette M. Parker Jan 2005

Techniques Employed To Capture Whooping Cranes In Central Florida, Martin J. Folk, Stephen A. Nesbitt, Stephen T. Schwikert, James A. Schmidt, Kathleen A. Sullivan, Thomas J. Miller, Stephen B. Baynes, Jeannette M. Parker

Proceedings of the North American Crane Workshop

During the course of re-introduction of a non-migratory flock of whooping cranes to Florida (1993-2002) a variety of techniques were used to capture 105 free-living birds. The most commonly used technique was hand-capture from a feed trough blind (45 birds). Whooping cranes were also captured by use of snares, several types of nets, and by hand. All techniques were relatively safe and posed little risk to the birds, a primary concern when dealing with rare birds. We found it useful to employ a diversity of techniques because some methods work better than others under differing circumstances. Capturing whooping cranes for …

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Head Stabilization In Whooping Cranes, Matthew R. Kinloch, Thomas W. Cronin, Glenn H. Olsen Jan 2005

Head Stabilization In Whooping Cranes, Matthew R. Kinloch, Thomas W. Cronin, Glenn H. Olsen

Proceedings of the North American Crane Workshop

The whooping crane (Grus americana) is the tallest bird in North America, yet not much is known about its visual ecology. How these birds overcome their unusual height to identify, locate, track, and capture prey items is not well understood. There have been many studies on head and eye stabilization in large wading birds (herons and egrets), but the pattern of head movement and stabilization during foraging is unclear. Patterns of head movement and stabilization during walking were examined in whooping cranes at Patuxent Wildlife Research Center, Laurel, Maryland USA. Four whooping cranes (1 male and 3 females) …

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Zur Nahrungsökologie Des Uhus Bubo Bubo In Der Mongolei = Feeding Ecology Of The Eagle Owl Bubo Bubo In Mongolia, Thomas Hoffmann, Michael Stubbe, D. Heidecke, R. Piechocki, R. Samjaa, J. Erfurt, D. Sumjaa Jan 2005

Zur Nahrungsökologie Des Uhus Bubo Bubo In Der Mongolei = Feeding Ecology Of The Eagle Owl Bubo Bubo In Mongolia, Thomas Hoffmann, Michael Stubbe, D. Heidecke, R. Piechocki, R. Samjaa, J. Erfurt, D. Sumjaa

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

This paper presents further results on the food ecology of the eagle owl in western Mongolia for the years 1984 to 1992. Additional to the already known sites we investigated two new resting places. At least 27 mammal and 17 bird species were recorded. The results confirm previous studies. Small to medium sized mammals (Cricetidae, Dipodidae, Arvicolidae) dominate the prey of the eagle owl whereas birds and invertebrates are less important.

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The Status And Impact Of The Rainbow Lorikeet (Trichoglossus Haematodus Moluccanus) In South-West Western Australia, Tamara Chapman Jan 2005

The Status And Impact Of The Rainbow Lorikeet (Trichoglossus Haematodus Moluccanus) In South-West Western Australia, Tamara Chapman

Agriculture reports

This report provides a summary of the biology and ecology of the rainbow lorikeet (Trichoglossus haematodus moluccanus), examines the status and management of the rainbow lorikeet in other regions; assesses the threats posed by the feral population in south-west Western Australia; and formulates the aims and objectives for an integrated pest management program.

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Past, Present, And Hypothetical Methods For Crane Reintroduction And Migration, David H. Ellis Jan 2005

Past, Present, And Hypothetical Methods For Crane Reintroduction And Migration, David H. Ellis

Proceedings of the North American Crane Workshop

In the early 1980’s the technique of releasing yearling parent-reared cranes was perfected with the Mississippi sandhill crane (Grus canadensis pulla). In the late 1980’s, we discovered that hand-reared yearlings could also be released with good expectation of survival in both migratory and nonmigratory situations. In the mid-1990’s, efforts expanded in many directions including (1) the use of various types of motorized vehicles to lead migrations, (2) the release of juveniles one by one into wild flocks in autumn or winter, and (3) the release of adult pairs. Here I outline new and proven techniques and those likely …

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Initial Training Of Cranes For An Airship Migration, David H. Ellis, Glenn H. Olsen, Jared Kwitowski Jan 2005

Initial Training Of Cranes For An Airship Migration, David H. Ellis, Glenn H. Olsen, Jared Kwitowski

Proceedings of the North American Crane Workshop

We describe the first year of our efforts to train cranes to accept the unnatural stimuli associated with being transported south in cages suspended beneath an airship. All 4 experimental cranes readily acclimated to entering a suspended cage and were trained to accept being jostled while in the cage, even when the cage was transported in the back of a pickup truck. With minor changes, the training protocol is ready for use in an actual airship migration.

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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 …

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Nesting Ecology And Productivity Of The Cuban Sandhill Crane On The Isle Of Youth, Cuba, Xiomara Galvez Aguilera, Vicente Berovides Alvarez, Felipe Chavez-Ramirez Jan 2005

Nesting Ecology And Productivity Of The Cuban Sandhill Crane On The Isle Of Youth, Cuba, Xiomara Galvez Aguilera, Vicente Berovides Alvarez, Felipe Chavez-Ramirez

Proceedings of the North American Crane Workshop

We studied nesting ecology and productivity of the Cuban sandhill crane in the Isle of Youth Cuba between 1997-2003. The nesting season extended from late march through June, but due to variable weather conditions could begin in February or extend through July. Overall, 71.1% of nests located produced eggs, while 84.1% of nests with eggs hatched at least one chick. Mean clutch size was 1.72 eggs. There were significant differences in hatching rates (G = 19.05, P < 0.01) and successful nests between years (G = 9.59, P < 0.10). Chicks/successful nest and rainfall during the breeding period (r = 0.6) were positively correlated. Percent successful nests was negatively correlated with total rainfall during the breeding season (r = -0.50). Causes of egg or nest failure included nest abandonment, predation, flooding, and infertility. In regards to breeding biology we recorded feather painting prior to nesting activity, false nests, and a re-nesting attempt after nest destruction. All nests were built on dry land. Cranes selected four of 11 habitat types present in the study area for nesting: open savannah (SNA) (24.2%), semi-closed natural savannah (SSC) (50.67%), open pine woodland (SPPA) (17.7%), and secondary savannah (SS) (7.7%). Palm density, seedlings, and forbs were lower at nest sites compared to random points, while ground cover of sand and litter was greater at nest sites. There were no significant differences in frequency of plant species among nest sites and random points (G = 3.78, P > 0.05). Tree species richness was less at nest sites, likely due to dominance of Tabebuia lepiodphylla and Byrsonima crassifolia species. Significant differences (G …

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Definition Of Subpopulations Within Mid-Continent Sandhill Cranes: A Nuclear Approach, K. L. Jones, G. L. Krapu, D. Brandt, M. V. Ashley Jan 2005

Definition Of Subpopulations Within Mid-Continent Sandhill Cranes: A Nuclear Approach, K. L. Jones, G. L. Krapu, D. Brandt, M. V. Ashley

Proceedings of the North American Crane Workshop

The evolution and population dynamics of migratory sandhill cranes (Grus canadensis) have been the subject of many studies. Although these previous studies have made significant progress explaining sandhill evolution on a large scale, they have been insufficient to explain the geographically partitioned variation in morphology seen in this species. The objective of this study is to quantify the population structure and/or gene flow within and between migratory sandhills using 12 microsatellite DNA loci and 192 samples collected across three populations. Contrary to the lower rates of gene flow seen between the three major migratory populations, high rates of …

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Annual Movements Of Pacific Coast Sandhill Cranes, Gary L. Ivey, Caroline P. Herziger, Thomas J. Hoffmann Jan 2005

Annual Movements Of Pacific Coast Sandhill Cranes, Gary L. Ivey, Caroline P. Herziger, Thomas J. Hoffmann

Proceedings of the North American Crane Workshop

The subspecies composition of migratory sandhill cranes (Grus canadensis) which stage and winter along the Lower Columbia River in northwest Oregon and southwest Washington is uncertain, but may include all 3 using the Pacific Flyway: lesser (G. c. canadensis), Canadian (G. c. rowani), and greater (G. c. tabida). However, the status of rowani has been debated. During 2001-02, we captured and marked 8 cranes using a noose line trapping technique, and attached Platform Transmitter Terminals (PTTs) to 6 to ascertain locations of their breeding areas, migration corridors and winter sites. Morphometric data …

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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 …

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An Obligation To Publish, Stephen A. Nesbitt Jan 2005

An Obligation To Publish, Stephen A. Nesbitt

Proceedings of the North American Crane Workshop

To be justifiable any wildlife study should strive to attain and describe new knowledge or refine existing understanding. Published results of field studies are often the products that conclude the study, though not always. But, as E.O. Wilson wrote in Consiliance: The Unity of Knowledge, “One of the structures of the scientific ethos is that a discovery does not exist until it is safely reviewed and in print.” Putting knowledge to page requires effort and, frequently, the abandonment of ones own ego. However, ego notwithstanding, this is not the only reason to publish research findings. Whether we are trying to …

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Injuries And Abnormalities Of Sandhill Cranes Captured In Florida, Stephen A. Nesbitt, Marilyn G. Spalding, Stephen T. Schwikert Jan 2005

Injuries And Abnormalities Of Sandhill Cranes Captured In Florida, Stephen A. Nesbitt, Marilyn G. Spalding, Stephen T. Schwikert

Proceedings of the North American Crane Workshop

Observations of gross pathological abnormalities were made during handling of sandhill cranes (Grus canadensis) captured for banding in Florida. One hundred fifty-six of 1,331 (11.7%) cranes examined showed evidence of one or more anomalies that were the result of disease, congenital deformity, or injury. Most frequent were abnormalities of the legs and feet, followed by abnormalities of the bill. Injuries of the eyes, head, and neck were also noted. Many of these birds were observed subsequent to banding and survived for several years with their injuries, though some never succeeded in reproducing.

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International Crane Foundation Sponsored Environmental Education: Conservation Of The Cuban Sandhill Crane, Korie M. Klink Jan 2005

International Crane Foundation Sponsored Environmental Education: Conservation Of The Cuban Sandhill Crane, Korie M. Klink

Proceedings of the North American Crane Workshop

The International Crane Foundation (ICF) has supported crane conservation, education and research activities in Cuba since 1995. Groups of American educators and researchers visit the island, contributing to annual crane festivals, school activities, survey work, assessments and cross-cultural communication. The goals of ICF’s environmental education program in Cuba are to: Disseminate information about ICF and crane conservation to American and Cuban educators and students, and to empower them to carry on ICF’s mission in their classrooms and communities; Participate actively in the Cuban Crane Festival while interacting with and supporting Cuban educators, biologists, and professionals; Develop activities, educational programs and …

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Genetic Assessment Of Non-Migratory Sandhill Crane Populations, K. L. Jones, F. Chavez-Ramirez, X. Galvez-Aguilera, L. Torella, M. V. Ashley Jan 2005

Genetic Assessment Of Non-Migratory Sandhill Crane Populations, K. L. Jones, F. Chavez-Ramirez, X. Galvez-Aguilera, L. Torella, M. V. Ashley

Proceedings of the North American Crane Workshop

Partial migration, the tendency of a segment of a population to remain resident while others migrate between their seasonal breeding and wintering ranges, is well known for many bird species. The objective of this study is to quantify the population structure and historical and recent gene flow patterns among non-migratory sandhills using microsatellite DNA genotyping of a large number of sandhills collected from six populations; and to assess if the population subdivisions are consistent with theories of partial migration. Our results indicate a complex web of gene flow within non-migratory populations, as well as between migratory and non-migratory populations. Gene …

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Proceedings Of The Ninth North American Crane Workshop, January 17–20, 2003, Table Of Contents Jan 2005

Proceedings Of The Ninth North American Crane Workshop, January 17–20, 2003, Table Of Contents

Proceedings of the North American Crane Workshop

No abstract provided.

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Reintroduction Techniques: Post-Release Performance Of Sandhill Cranes (1) Released Into Wild Flocks And (2) Led On Migration By Ultralight Aircraft, Richard P. Urbanek, Joseph W. Duff, Scott R. Swengel, Lara E. A. Fondow Jan 2005

Reintroduction Techniques: Post-Release Performance Of Sandhill Cranes (1) Released Into Wild Flocks And (2) Led On Migration By Ultralight Aircraft, Richard P. Urbanek, Joseph W. Duff, Scott R. Swengel, Lara E. A. Fondow

Proceedings of the North American Crane Workshop

Two methods of reintroducing a migratory population of whooping cranes (Grus americana) were tested with costume/ isolation-reared juvenile greater sandhill cranes (G. canadensis tabida): (1) release into wild flocks during autumn staging and (2) leading on autumn migration by ultralight aircraft. Birds in the first group were released singly, and all integrated quickly into the wild flocks and adopted similar behavioral patterns. Birds in the second group were led to winter on an inland site on the Gulf Coast of Florida. Most of the birds led by ultralight aircraft remained in their juvenile cohort through the …

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Sandhill Crane Use Of Managed Chufa Wetlands In New Mexico, John P. Taylor, Loren M. Smith Jan 2005

Sandhill Crane Use Of Managed Chufa Wetlands In New Mexico, John P. Taylor, Loren M. Smith

Proceedings of the North American Crane Workshop

Natural wetland food plants help meet energetic requirements for sandhill cranes (Grus canadensis). Chufa (Cyperus esculentus) tubers were found to be a prominent item in the winter diet of cranes in New Mexico and Texas. In 1996 and 1997, chufa production was compared among mowing, discing, and sustained-flooding treatments intended to enhance chufa tuber growth. Sandhill crane numbers were monitored on wetlands during winter flooding to determine treatment preferences. No differences in sandhill crane use of treated wetlands were found in 1996, however in 1997, crane use was higher on disked field than sustained flood fields …

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An Adaptive Approach To Channel Management On The Platte River, Kent Pfeiffer, Paul Currier Jan 2005

An Adaptive Approach To Channel Management On The Platte River, Kent Pfeiffer, Paul Currier

Proceedings of the North American Crane Workshop

The mission of the Platte River Whooping Crane Maintenance Trust is to protect and manage habitat in the Platte valley for whooping cranes, sandhill cranes, and other migratory birds. The plan for meeting this mission calls for the creation and maintenance of eleven habitat complexes distributed through the central Platte valley. Each habitat complex is intended to consist of 1,000 ha of wet meadows and adjacent roost habitat of open, unvegetated river channel. Reduced flows in the river have caused its channel to narrow with banks that are often heavily wooded. Formerly mobile sand bars have stabilized and support dense …

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Migration Chronology, Routes, And Distribution Of Pacific Flyway Population Lesser Sandhill Cranes, Michael J. Petrula, Thomas C. Rothe Jan 2005

Migration Chronology, Routes, And Distribution Of Pacific Flyway Population Lesser Sandhill Cranes, Michael J. Petrula, Thomas C. Rothe

Proceedings of the North American Crane Workshop

Managers of migratory game birds require accurate information about bird movements to delineate populations, protect important habitats, and regulate harvest. Data describing movements of sandhill cranes (Grus canadensis) belonging to the Pacific Flyway Population (PFP) are lacking. We used satellite telemetry to monitor movements of PFP lesser sandhill cranes (Grus c. canadensis) captured in the upper Cook Inlet and Bristol Bay regions of Alaska. Satellite transmitters were deployed on 19 flightless young (colts) and 3 adults over 3-years (2000-2002). Chronology, routes, and stopover or staging areas were identified for fall and spring migration periods. On average, …

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Effects Of Human Disturbances On The Behavior Of Wintering Ducks, Melissa L. Pease, Robert K. Rose, Mark J. Butler Jan 2005

Effects Of Human Disturbances On The Behavior Of Wintering Ducks, Melissa L. Pease, Robert K. Rose, Mark J. Butler

Biological Sciences Faculty Publications

Human activity causes wintering waterfowl to expend energy to avoid humans at a time in their annual cycle when energy conservation is important to survival, migration, and breeding reserves. Understanding the effects of recreational activities on waterfowl is important to managing natural resource areas where migratory birds depend on wetland habitat for resting and feeding. We investigated responses of 7 species of dabbling ducks to 5 different experimental human activities, (a pedestrian, a bicyclist, a truck traveling at 2 different speeds, and an electric passenger tram). Responses of ducks depended on type of disturbance, species, and distance from disturbances. Most …

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Effects Of Human Disturbances On The Behavior Of Dabbling Ducks, Melissa Lynn Pease Apr 2001

Effects Of Human Disturbances On The Behavior Of Dabbling Ducks, Melissa Lynn Pease

Biological Sciences Theses & Dissertations

Disturbance of wintering and migrating birds by human activities can cause birds to expend energy in avoidance of humans and reduces the time available for resting and feeding at a time in the annual cycle when fat deposition and energy conservation are important. Also, human disturbances can effectively cause habitat loss by displacing birds from feeding or resting habitat. Managers of natural resources are increasingly faced with decisions about the types and amounts of public use that should be allowed without lowering the value of the resource for wildlife. In order for managers to make decisions about how to minimize …

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Natural Fertility In Whooping Cranes And Mississippi Sandhill Cranes At Patuxent Wildlife Research Center, Jane M. Nicolich, George F. Gee, David H. Ellis, Scott G. Hereford Jan 2001

Natural Fertility In Whooping Cranes And Mississippi Sandhill Cranes At Patuxent Wildlife Research Center, Jane M. Nicolich, George F. Gee, David H. Ellis, Scott G. Hereford

Proceedings of the North American Crane Workshop

The first fertile whooping crane (Grus americana; WC) egg produced through natural breeding at Patuxent Wildlife Research Center (patuxent) was laid in 1991. Prior to that time, all fertile whooping crane eggs were the result of artificial insemination. Since 1991, eight different whooping crane pairs at Patuxent have produced fertile eggs through natural breeding. Mean fertility averages over years for each pair range from 40% to 93%. Fertility rates for each pair also vary greatly between years, from 0% to 100%, but the causes of the variance are unknown. Experiences with natural fertility in Mississippi sandhill cranes (G …

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Counting Cranes: How Much Effort Is Enough?, Douglas H. Johnson, Roderick C. Drewien, Douglas S. Benning Jan 2001

Counting Cranes: How Much Effort Is Enough?, Douglas H. Johnson, Roderick C. Drewien, Douglas S. Benning

Proceedings of the North American Crane Workshop

Accurate population estimates of sandhill cranes (Grus canadensis) are important because management decisions, such as establishing hunting regulations, are based on those estimates. Counts often are made during aerial surveys when the cranes are congregated. A complete census may be feasible if the area to be surveyed is small and adequate resources are available. For large areas, resources may be inadequate for a census so partial counts (sample surveys) are made. Because cranes are gregarious, the counts in a sample of units may contain either a disproportionately large, or a disproportionately small, fraction of the total, leading to …

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Nocturnal Roost Site Selection And Diurnal Habitat Use By Sandhill Cranes During Spring In Central Nebraska, Craig A. Davis Jan 2001

Nocturnal Roost Site Selection And Diurnal Habitat Use By Sandhill Cranes During Spring In Central Nebraska, Craig A. Davis

Proceedings of the North American Crane Workshop

During spring 1998 and 1999, the Platte River Whooping Crane Maintenance Trust conducted ground and aerial surveys of staging sandhill cranes (Grus canadensis; hereafter, cranes) to detennine roost site selection and habitat-use patterns along a l20-Ian stretch of the Platte River in south-central Nebraska. Cranes peaked at 232,023 during 22-28 March 1998 and 206,074 during 28 Februaty-6 March 1999 in the study area, a portion of the total crane staging area in the Platte River Valley. Diurnal observations showed that 48% of the cranes were in com fields, 34% in lowland grasslands, 13% in alfalfa fields, and 5% …

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