Open Access. Powered by Scholars. Published by Universities.®

Population Biology Commons™

Open Access. Powered by Scholars. Published by Universities.®

University of Nebraska - Lincoln

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1201 - 1230 of 1363

Full-Text Articles in Population Biology

A New Subspecies Of Brephidium Isophthalma (Lycaenidae: Polyommatinae) From Coastal South Carolina, Harry Pavulaan, Ronald R. Gatrelle Apr 1999

A New Subspecies Of Brephidium Isophthalma (Lycaenidae: Polyommatinae) From Coastal South Carolina, Harry Pavulaan, Ronald R. Gatrelle

The Taxonomic Report of the International Lepidoptera Survey

Brephidium isophthalma pseudofea was described in 1873 from the Florida Keys, United States. The ventral ground color of the wings in topotypical pseudofea is a yellowish brown. The antennal clubs of pseudofea have prominent orange red tips. The ventral surface of the abdomen of pseudofea is broadly white to very light gray and usually extends halfway around the sides of the light to medium brown abdomen. Specimens of B. isophthalma from coastal South Carolina differ greatly from topotypical pseudofea. Accordingly, B. i. insularus is described as a new subspecies from coastal South Carolina. The antennal clubs …

Go to article

An Evolutionary Subspecific Assessment Of Deciduphagus Henrici (Lycaenidae) Based On Its Utilization Of Ilex And Non-Ilex Hosts: Description Of A Third Ilex Associated Subspecies; Designation Of A Neotype And Type Locality For Deciduphagus Irus; With Appendix, Ronald R. Gatrelle Mar 1999

An Evolutionary Subspecific Assessment Of Deciduphagus Henrici (Lycaenidae) Based On Its Utilization Of Ilex And Non-Ilex Hosts: Description Of A Third Ilex Associated Subspecies; Designation Of A Neotype And Type Locality For Deciduphagus Irus; With Appendix, Ronald R. Gatrelle

The Taxonomic Report of the International Lepidoptera Survey

Deciduphagus henrici subsists as six subspecies which have evolved into two distinct larval host associated groups of three taxa each. Group one is composed of those taxa which utilize primarily Ilex (holly, various species) as their host. They inhabit the non-montane area of the southeastern United States and up the Atlantic coast to at least southern New Jersey. They are: D. h. margaretae (T. L. Deland, Volusia County, Florida) occupying east-coastal to south central Florida; D. h. viridissima (T. L. Nag’s Head, Dare County, North Carolina) occupying the upper Outer Banks area of North Carolina …

Go to article

A Comment On Friedlander’S Asterocampa (Nymphalidae, Apaturinae): Designation Of Neotypes For A. Celtis And A. Clyton, Ronald R. Gatrelle Jan 1999

A Comment On Friedlander’S Asterocampa (Nymphalidae, Apaturinae): Designation Of Neotypes For A. Celtis And A. Clyton, Ronald R. Gatrelle

The Taxonomic Report of the International Lepidoptera Survey

Friedlander’s 1986 [1987] treatment of the southeastern United States. taxa of Asterocampa is examined. Neotypes of A. celtis and A. clyton are designated from Burke County, Georgia to help stabilize the status of these taxa and aid in any future research. Asterocampa celtis is currently known to exist within at least 40 km of A. c. reinthali in Georgia. Their proximity, without integration, suggests evolutionary distance, perhaps even speciation. It is proposed that A. celtis is descended from A. c. alicia, and alicia from a Mexican refugium. Asterocampa clyton and A. …

Go to article

Subspecific Status Of Southeastern U.S. Megathymus Cofaqui And M. Yuccae: Renaming Of The Florida Subspecies Of M. Cofaqui, Ronald R. Gatrele Jan 1999

Subspecific Status Of Southeastern U.S. Megathymus Cofaqui And M. Yuccae: Renaming Of The Florida Subspecies Of M. Cofaqui, Ronald R. Gatrele

The Taxonomic Report of the International Lepidoptera Survey

Megathymus cofaqui and M. yuccae are both represented in the southeastern United States by two subspecies. The type locality of both M. y. yuccae and M. c. cofaqui is the area of Burke/Screven counties Georgia. Each of their subspecies are primarily Floridian, with M. y. buchholzi extending along the immediate coast of Georgia into southern South Carolina. Topotypes of M. cofaqui from Burke County, Georgia, and Aiken County, South Carolina are phenotypically indistinguishable from both the holotype of M. cofaqui and topotypes of M. c. harrisi. Thus, M …

Go to article

Plant Hybrid Zones And Insect Host Range Expansion, Diana Pilson Jan 1999

Plant Hybrid Zones And Insect Host Range Expansion, Diana Pilson

Diana Pilson Publications

The hybrid bridge hypothesis suggests that plant hybrids ‘‘bridge’’ the genetic gap between actual and potential host species, and that, for this reason, herbivorous insects are more likely to evolve an expanded host range in the presence of hybrids. While intuitively appealing, the hypothesis has two implicit assumptions: that phenotypic gaps between potential hosts limit host range, and that characters controlling host use are additively inherited in plant hybrids. Evaluation of these assumptions suggests that operation of the hybrid bridge hypothesis is relatively uncommon. In addition, the hypothesis has not been well integrated into existing theoretical and empirical work on …

Go to article

Experimental Infections Of Muskoxen (Ovibos Moschatus) And Domestic Sheep With Umingmakstrongylus Pallikuukensis (Nematoda: Protostrongylidae): Parasite Development, Population Structure, And Pathology, Susan J. Kutz, Eric P. Hoberg, Lydden Polley Jan 1999

Experimental Infections Of Muskoxen (Ovibos Moschatus) And Domestic Sheep With Umingmakstrongylus Pallikuukensis (Nematoda: Protostrongylidae): Parasite Development, Population Structure, And Pathology, Susan J. Kutz, Eric P. Hoberg, Lydden Polley

Harold W. Manter Laboratory of Parasitology: Faculty and Staff Publications

Three captive muskoxen (Ovibos moschatus) were successfully infected with third-stage larvae of Umingmakstrongylus pallikuukensis digested or emerged from the slugs Deroceras reticulatum and D. laeve, for the first time completing the life cycle of this parasite under experimental conditions. The course of parasite development and patency was followed for 26 months post infection (p.i.) using fecal examinations and radiography. The prepatent periods in two of the muskoxen were 91 and 95 days and the patent period in one extended for 23 months. Larval production peaked 13–14 months p.i. On postmortem of two of the muskoxen at months …

Go to article

Two New Nymphalidae From Western North Carolina: New Subspecies Of Speyeria Aphrodite And Phyciodes Batesii, Ronald R. Gatrelle Dec 1998

Two New Nymphalidae From Western North Carolina: New Subspecies Of Speyeria Aphrodite And Phyciodes Batesii, Ronald R. Gatrelle

The Taxonomic Report of the International Lepidoptera Survey

Two new subspecies are described from Macon County, North Carolina, United States. Speyeria aphrodite cullasaja is characterized by dorsal melanism, especially in females, by usually lacking the dorsal FW basal spots in cell Cu1 and Cu2, and by a narrowed buff marginal band on the ventral HW (sometimes absent in females). Phyciodes batesii maconensis males are characterized by wholly yellow ventral hind wings devoid of any dark marginal dusting or whitish crescents; and females occasionally possessing, lightly dusted, brown margins and rarely having a silvered marginal ventral HW spot. PPhyciodes batesii maconensis larvae are gregarious Aster feeders. Females are …

Go to article

The Rediscovery, Taxonomy, And Biology Of Chlosyne Gorgone Gorgone And Chlosyne Ismeria (Nymphalidae) In Burke County, Georgia, Ronald R. Gatrelle Nov 1998

The Rediscovery, Taxonomy, And Biology Of Chlosyne Gorgone Gorgone And Chlosyne Ismeria (Nymphalidae) In Burke County, Georgia, Ronald R. Gatrelle

The Taxonomic Report of the International Lepidoptera Survey

On April 24, 1993 a colony of Chlosyne gorgone gorgone was found in Orangeburg County, South Carolina, United States. This led to the rediscovery on April 27, 1993 of C. g. gorgone at its type locality in Burke County, Georgia. This species had not been seen or collected anywhere in east coastal Georgia or coastal South Carolina since its description in 1810. The type locality is xeric, scrub oak sandhill. This habitat is generally unsuitable for the survival of later broods. The larvae of nominate gorgone have only been found on Helianthus divaricatus. Topotypical gorgone differ slightly, …

Go to article

An Addendum To Anthocharis Midea Dos Passos And Klots 1969: Description Of A New Subspecies From Texas, Ronald R. Gatrelle Oct 1998

An Addendum To Anthocharis Midea Dos Passos And Klots 1969: Description Of A New Subspecies From Texas, Ronald R. Gatrelle

The Taxonomic Report of the International Lepidoptera Survey

This paper verifies and expands upon the information presented by dos Passos and Klots in their 1969 systematic revision of Anthocharis midea. Their restriction of the range of A. midea midea to the coastal islands and immediate coast of Georgia and South Carolina, United States is confirmed and expanded north into southern coastal North Carolina. Their range of A. m. annickae is expanded southward from Virginia to central Georgia. A new subspecies, A. midea texana, is described from Texas. Texana is annickae’s ancestor. It differs from annickae only in having greatly reduced black scaling …

Go to article

Population Biology Of Intraspecific Polyploidy In Grasses, Kathleen H. Keeler Jan 1998

Population Biology Of Intraspecific Polyploidy In Grasses, Kathleen H. Keeler

School of Biological Sciences: Faculty Publications

Polyploidy is the duplication of an entire nuclear genome, whether diploid or higher level (Stebbins, 1971; Thompson & Lumaret, 1992) and a frequent occurrence in plants. Stebbins (1971) estimated that 30-35% of flowering plant species are polyploid, and that many more had a polyploid event in their evolutionary history, including all members of such important families as the Magnoliaceae, Salicaceae, and Ericaceae. Goldblatt (1980) estimated 55%, but probably up to 75%, of monocotyledons had at least one polyploid event in their history, using the criterion that if the species has a base number higher than n=13 it is derived …

Go to article

Spring Population Estimates Of Rocky Mountain Greater Sandhill Cranes In Colorado, Douglas S. Benning, Roderick C. Drewien, Douglas H. Johnson, Wendy M. Brown, Erwin L. Boeker Jan 1997

Spring Population Estimates Of Rocky Mountain Greater Sandhill Cranes In Colorado, Douglas S. Benning, Roderick C. Drewien, Douglas H. Johnson, Wendy M. Brown, Erwin L. Boeker

Proceedings of the North American Crane Workshop

We developed an aerial survey to estimate the Rocky Mountain Population (RMP) of greater sandhill cranes (Grus canadensis tabidn) (greaters) annually during March 1984-95 in the San Luis Valley, Colorado (SLV). We flew aerial transects covering a 21,220-ha contiguous area. Aerial photographs of crane flocks were taken to correct for estimation errors. We employed ground surveys to correct for presence of lesser sandhill cranes (G. c. canadensis) (lessers), which mixed with RMP cranes. To adjust for RMP cranes not in the survey area, we made ground counts in traditional use areas outside the SLY. During 1984-95, 5 …

Go to article

Home Range And Habitat Use By Isolation-Reared Sandhill Cranes, Wenrui Duan, Theodore A. Bookhouts, Richard P. Urbanek Jan 1997

Home Range And Habitat Use By Isolation-Reared Sandhill Cranes, Wenrui Duan, Theodore A. Bookhouts, Richard P. Urbanek

Proceedings of the North American Crane Workshop

We isolation-reared, placed radio transmitters on, and released 38 greater sandhill cranes (Grus canadensis tabida) on Seney National Wildlife Refuge (Seney) in 1988-90 to develop procedures for initiating new populations of cranes. Here we report on habitat selection by breeding birds with functional radio transmitters. Home ranges established by 6 cranes in 1992, when they were 2 to 4 years old, averaged 199±50.8 (SE) ha (harmonic mean method, 75 % utilization) and were of 2 types: feeding grounds separated from nesting habitat and feeding grounds adjacent to nesting habitat. Home ranges consisted of 36% emergent palustrine wetlands, 28% …

Go to article

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 …

Go to article

Use Of Dredged Material To Construct Winter Whooping Crane Habitat, Darrell E. Evans, Thomas V. Stehn Jan 1997

Use Of Dredged Material To Construct Winter Whooping Crane Habitat, Darrell E. Evans, Thomas V. Stehn

Proceedings of the North American Crane Workshop

Aransas National Wildlife Refuge (ANWR) and nearby coastal marshes serve as the winter home for the only natural flock of whooping cranes (Grus americana), In recent years shoreline erosion and the subsequent loss of wintering habitat have been observed on the refuge adjacent to the GulfIntracoastal Waterway (GIWW). In 1988 the U.S. Army Corps of Engineers (USACE) District, Galveston, Texas, and U.S. Fish and Wildlife Service (USFWS) entered into an informal agreement to attempt to slow shoreline/habitat loss on the refuge. Efforts to curtail habitat loss have included armoring the most erosive reaches with temporary concrete erosion control …

Go to article

The Effect Of Disturbance On The Reproduction And Management Of Captive Cranes, Claire M. Mirande, James W. Carpenter, Ann M. Burke Jan 1997

The Effect Of Disturbance On The Reproduction And Management Of Captive Cranes, Claire M. Mirande, James W. Carpenter, Ann M. Burke

Proceedings of the North American Crane Workshop

A retrospective analysis of egg laying histories and observations of crane pairs at the International Crane Foundation and the Patuxent Wildlife Research Center indicates that disturbance associated with captivity has adverse impacts on captive breeding. Females on public display laid significantly fewer eggs than those off display (P < 0.05). Crane pairs moved to other pens (other than adjacent pens) or hetween facilities laid slightly fewer eggs than those birds which were not moved. although the results were not statistically significant (P = 0.188). Pen design and construction also appeared to have adverse impacts on breeding. In addition, human activities, intraspecific interactions, and rearing methods influence a bird's response to disturbance, and, therefore, these factors must also be considered in an effective crane management program. Modifying procedures to minimize disturbance, timing necessary disturbances after the breeding and molt seasons, and carefully monitoring birds for signs of stress can result in increased reproductive potential for captive, endangered cranes.

Go to article

Subspecies Composition Of Sandhill Crane Harvest In North Dakota, 1968-94, William L. Kendall, Douglas H. Johnson, Stanley C. Kohn Jan 1997

Subspecies Composition Of Sandhill Crane Harvest In North Dakota, 1968-94, William L. Kendall, Douglas H. Johnson, Stanley C. Kohn

Proceedings of the North American Crane Workshop

North Dakota is a major fall staging area for the Mid-continent Population (MCP) of sandhill cranes (Grus canadensis), which is composed of 3 subspecies: the greater (G. c. tabida), Canadian (G. c. rawani), and lesser (G. c. canadensis). The number of cranes killed by hunters in North Dakota averaged 6,793 during the 1990-94 seasons, ranking second highest among crane-hunting states. The distribution of harvest among subspecies is important, due to concerns about the poorly known status of these subspecies, especially the greater. We estimated subspecies composition of the harvest in North Dakota by …

Go to article

Sandhill Crane Use Of The Mid-Pecos Valley Of Eastern New Mexico, James B. Montgomery Jr. Jan 1997

Sandhill Crane Use Of The Mid-Pecos Valley Of Eastern New Mexico, James B. Montgomery Jr.

Proceedings of the North American Crane Workshop

Sandhill cranes (Grus canadensis) were monitored during winters 1989-94 in the mid-Pecos River Valley of eastern New Mexico to detennine how many used this region following a population decline in the 1980's. Numbers annually increased to a late October/early November peak (X = 7,017), fluctuated around 6,000 through December, declined in January (X = 3,531), and again peaked in February/early March (X = 5,737). Annual crane use-days (weekly counts X 7) varied from 500,545 to 1,007,673 (X = 760,606). Cranes foraged mainly in corn and sorghum stubble and alfalfa fields. Crop averages (ha) during 1990-92 were alfalfa 21,449, …

Go to article

Monogamy And Productivity In Sandhill Cranes, Stephen A. Nesbitt, Thomas C. Tacha Jan 1997

Monogamy And Productivity In Sandhill Cranes, Stephen A. Nesbitt, Thomas C. Tacha

Proceedings of the North American Crane Workshop

Marked pairs of Florida (Grus canadensis pratensis) and greater sandhill cranes (G. c. tabida) were monitored for 426 pair-years. Among pair members, females averaged 3.7 ± 3.6 (SD) years older than males. Pair longevity was not correlated with pair productivity (P ~ 0.279) for pairs that were together >3 years. Forty-four percent of 72 Florida sandhill crane pair bonds were broken during the study, 67.7% due to death and 32.3 % to divorce. Among both Florida and greater sandhill cranes, the incidence of divorce was related to a failure to reproduce; 52.6% of pairs that failed to produce …

Go to article

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.

Go to article

Sandhill Crane Hunts In The Rio Grande Valley And Southwest New Mexico, C. Gregory Schmitt, Barry Hale Jan 1997

Sandhill Crane Hunts In The Rio Grande Valley And Southwest New Mexico, C. Gregory Schmitt, Barry Hale

Proceedings of the North American Crane Workshop

Annual limited permit hunting seasons for sandhill cranes (Grus canadensis) were initiated in southwestern New Mexico (SWNM) in 1982 and in the middle Rio Grande Valley (MRGV) in 1986. Within the MRGV and SWNM are wintering areas for 3 migratory subspecies, including the lesser sandhill crane (G. c. canadensis) (lessers). Canadian sandhill crane (G. c. rowani) (Canadians), and greater sandhill crane (G. c. tabida) (greaters). We summarized annual season dates, bag limits, requirements for permits, procedures for examination of crane specimens at check stations, number of hunters, estimated harvest, mean harvest per …

Go to article

Pair Formation By Color-Marked Whooping Cranes On The Wintering Grounds, Thomas V. Stehn Jan 1997

Pair Formation By Color-Marked Whooping Cranes On The Wintering Grounds, Thomas V. Stehn

Proceedings of the North American Crane Workshop

Observations were made of color-marked whooping cranes (Grus americana) at Aransas during the 1977-94 winters. Suhadult cranes wintered near their juvenile home ranges in flocks averaging 3.12 birds. One and 2 winters prior to nesting, subadults at Aransas tended to form duos apart from other subadults. Frequencies of association 1 year prior to nesting averaged 65.4%. However, 27.7 % of pair bonds (n = 18) formed during spring migration or on the breeding grounds without any observed prior association at Aransas. Sixty-eight banded cranes formed pairs. Pair members averaged 1.06 years difference in age. Winter territories of adults …

Go to article

Recent Advances In Scheduling Strategies And Practical Techniques In Crane Artificial Insemination, Scott R. Swengel, Monica L. Tuite Jan 1997

Recent Advances In Scheduling Strategies And Practical Techniques In Crane Artificial Insemination, Scott R. Swengel, Monica L. Tuite

Proceedings of the North American Crane Workshop

We analyzed fertility patterns of 339 eggs laid 1985-93 at the International Crane Foundation by cranes whose sole means of fertility was artificial insemination (AI). Ten of 15 crane species were studied. Fertility rates increased significantly (P < 0.05) with (I) higher sperm density, (2) greater sperm motility, and (3) 2 vs. 1 vs. 0 inseminations 4-7 days before oviposition. Semen sample size was inversely related to sperm density and had no strong relationship with egg fertility. Inseminations less than 2.5-3.0 days before an egg is laid are probably too late to contribute to fertilizing the egg but may contribute substantially to fertilizing the next egg. We also describe practical knowledge gained during the past 10 years that apply to certain species or situations. Wattled cranes (Bugeranus carunculatus) have a long fertile period post-AI (up to 16 days), but may require more careful methods and special AI scheduling strategies. We also describe techniques for AI just after oviposition that are especially beneficial for Siberian cranes (Grus leucogeranus), and methods for maximizing sample delivery to the female.

Go to article

History Of Breeding Pairs And Nesting Sites Of The Mississippi Sandhill Crane, Jacob M. Valentine Jr., Scott G. Hereford Jan 1997

History Of Breeding Pairs And Nesting Sites Of The Mississippi Sandhill Crane, Jacob M. Valentine Jr., Scott G. Hereford

Proceedings of the North American Crane Workshop

Thirty-four Composite Nesting Areas (CNA's) of endangered Mississippi sandhill cranes (Grus canadensis pulla) within the current breeding range in Jackson County, Mississippi, were located from 1965 to 1996, primarily by ground searching. Of those 34 CNA's located, 28 were on I of the 3 refuge units and 6 were off but adjacent to the refuge's Ocean Springs Unit. Five of the CNA's had 2-3 distinct smaller core nesting areas within. Two CNA's had active nests in more than 20 years, and those nests accounted for 11 % of the total. Nine CNA's accounted for 130 (63%) of the …

Go to article

Food And Energy Intake Rates Of Wintering Whooping Cranes Foraging On Two Selected Food Items, Felipe Chavez-Ramirez, Jay T. Nelson, R. Douglas Slack Jan 1997

Food And Energy Intake Rates Of Wintering Whooping Cranes Foraging On Two Selected Food Items, Felipe Chavez-Ramirez, Jay T. Nelson, R. Douglas Slack

Proceedings of the North American Crane Workshop

Number, mass, and potential energy of food items consumed by wintering whooping cranes (Grus americana) foraging on blue crab (Callinectes sapidus) and woltberry (Lycium carolinianum) fruit were estimated and compared between 2 consecutive winter periods. Mass consumed was determined through field observations by quantifying the number of items taken per unit time and the average, or modal, weight of each food item determined from collections. Gross energy intake was determined by calculating the product of mass consumed times gross energy (kJ/g) of each food item. Potential energy retained was calculated by determining metabolizable energy …

Go to article

Results Of Eight Years Of Predator Control To Enhance Sandhill Crane Production On Malheur National Wildlife Refuge, Oregon, Gary L. Ivey Jan 1997

Results Of Eight Years Of Predator Control To Enhance Sandhill Crane Production On Malheur National Wildlife Refuge, Oregon, Gary L. Ivey

Proceedings of the North American Crane Workshop

Because of a 21 % decline in breeding pairs of greater sandhill cranes (Grus canadensis tabida) on Malheur National Wildlife Refuge from 1971 to 1985, a predator control program was initiated in 1986 to enhance production. The primary cause for the decline was low recruitment of young due to high predation by ravens (Corvus corax). raccoons (Procyon lotor), and coyotes (Canis latrans), On average, predators destroyed 46% of all crane nests and 90% of the prefledged colts. Mink (Mustela vison) were added to the program in 1993 after a study …

Go to article

Use Of Ultralight Aircraft For Introducing Migratory Crane Populations, Kent R. Clegg, James C. Lewis, David H. Ellis Jan 1997

Use Of Ultralight Aircraft For Introducing Migratory Crane Populations, Kent R. Clegg, James C. Lewis, David H. Ellis

Proceedings of the North American Crane Workshop

Greater sandhill cranes (Grus canadensis tabida) were used as the research surrogate for whooping cranes (Grus americana) to determine if captive-reared cranes could be led by an ultralight aircraft (UL) along a migration route and if, after release on a wintering area, they would integrate with wild cranes and migrate north in spring to their natal area without assistance. In 1995, KRC raised 15 cranes to fledging and trained them to respond to his vocal imitation of a sandhill crane brood call. Chicks learned to follow him as he walked, drove an all-terrain vehicle (ATV) , …

Go to article

Woody Vegetation Expansion And Continuing Declines In Open Channel Habitat On The Platte River In Nebraska, Paul J. Currier Jan 1997

Woody Vegetation Expansion And Continuing Declines In Open Channel Habitat On The Platte River In Nebraska, Paul J. Currier

Proceedings of the North American Crane Workshop

Aerial videography in 1988 and 1994 of the same selected segments of the Big Bend reach of the Platte River in central Nebraska was compared. During this 6-year period, channel area declined 4 to 41 % (median 26%). In river segments where the channel had already narrowed significantly and at sites where channel habitat is actively managed declines were less (17-18%). These substantial changes occurred during a time that included a relatively low flow period (1990-92). Flows during the summer gertttination and establishment period (mid-May through August) for cottonwood (Populus deltoides) and willow (Salix spp.), the …

Go to article

Use Of Cross-Fostered Whooping Cranes As Guide Birds, Roderick C. Drewien, Wendy L. Munroe, Kent R. Clegg, Wendy M. Brown Jan 1997

Use Of Cross-Fostered Whooping Cranes As Guide Birds, Roderick C. Drewien, Wendy L. Munroe, Kent R. Clegg, Wendy M. Brown

Proceedings of the North American Crane Workshop

We tested the use of wild, cross-fostered, adult whooping cranes (Grus americana) as guide birds to adopt and lead young whooping cranes on a predetermined migration route in the Rocky Mountains. We captured 3 wild adults (1 male and 1 female in 1993, 1 male in 1994) during winter at the Bosque del Apache National Wildlife Refuge (Bosque NWR), New Mexico, and moved them to captive facilities 80 kIn from Grays Lake National Wildlife Refuge (Grays Lake), Idaho, where they had originally been raised by sandhill crane (G. canadensis) foster parents. Adults were held for 6.75-7 …

Go to article

Modeling The Population Dynamics Of Gulf Coast Sandhill Cranes, Douglas H. Johnson, William L. Kendall Jan 1997

Modeling The Population Dynamics Of Gulf Coast Sandhill Cranes, Douglas H. Johnson, William L. Kendall

Proceedings of the North American Crane Workshop

The Mid-continent Population of sandhill cranes (Grus canadensis) has a large geographic range. contains nearly 500,000 birds, and is hunted in much of its range. The population includes 3 subspecies; the numbers of 2 of these are uncertain, and they should be afforded protection from hunting that would be detrimental to their population. The 2 subspecies of concern tend to concentrate in the eastern part of the Great Plains during fall and spring and to winter along the Gulf Coast in Texas. This paper uses the limited information availahle ahout the Gulf Coast subpopulation in a model. We …

Go to article

Habitat Use By Migrant Whooping Cranes In Saskatchewan, Brian W. Johns, Eric J. Woodsworth, Ed A. Driver Jan 1997

Habitat Use By Migrant Whooping Cranes In Saskatchewan, Brian W. Johns, Eric J. Woodsworth, Ed A. Driver

Proceedings of the North American Crane Workshop

We investigated habitat use by migrating whooping cranes (Grus americana) in Saskatchewan between 1986 and 1990. At foraging and roosting sites and a sample of randomly selected sites we measured various habitat parameters. Palustrine and lacustrine wetlands were the most frequently used wetlands. Temporary and seasonal wetlands were the primary roost habitat during spring migration, and semi-permanent and permanent wetlands were frequently used during the fall. Cranes were attracted to areas of higher than average wetland density. Land use within 2 km of roost sites was intensively modified by man. Cereal crops were the most used feeding areas. …

Go to article

First Prev Next Last