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Articles 1561 - 1590 of 1892

Full-Text Articles in Terrestrial and Aquatic Ecology

Ecological Games In Space And Time: The Distribution And Abundance Of Antarctic Krill And Penguins, Suzanne Alonzo, Paul Switzer, Marc Mangel Jan 2003

Ecological Games In Space And Time: The Distribution And Abundance Of Antarctic Krill And Penguins, Suzanne Alonzo, Paul Switzer, Marc Mangel

Faculty Research & Creative Activity

The distribution and abundance of organisms are affected by behaviors, such as habitat selection, foraging, and reproduction. These behaviors are driven by interactions within and between species, environmental conditions, and the biology of the species in-volved. Although extensive theoretical work has explored predator–prey dynamics, these models have not considered the impact of behavioral plasticity and life-history trade-offs on predicted patterns. We apply a modeling method that allows the consideration of a spatial, dynamic ecological game between predators and prey using a life-history perspec-tive. As an illustrative example, we model the habitat selection of Antarctic krill and penguins during the time …


Ecological Games In Space And Time: The Distribution And Abundance Of Antarctic Krill And Penguins, Suzanne H. Alonzo, Paul V. Switzer, Marc Mangel Jan 2003

Ecological Games In Space And Time: The Distribution And Abundance Of Antarctic Krill And Penguins, Suzanne H. Alonzo, Paul V. Switzer, Marc Mangel

Faculty Research & Creative Activity

The distribution and abundance of organisms are affected by behaviors, such as habitat selection, foraging, and reproduction. These behaviors are driven by interactions within and between species, environmental conditions, and the biology of the species in-volved. Although extensive theoretical work has explored predator–prey dynamics, these models have not considered the impact of behavioral plasticity and life-history trade-offs on predicted patterns. We apply a modeling method that allows the consideration of a spatial, dynamic ecological game between predators and prey using a life-history perspec-tive. As an illustrative example, we model the habitat selection of Antarctic krill and penguins during the time …


The Tadpole Of Phrynobatrachus Mababiensis Fitzsimons, 1932 (Anura, Ranidae, Petropedetinae), Rafael O. De Sá, Alan Channing Jan 2003

The Tadpole Of Phrynobatrachus Mababiensis Fitzsimons, 1932 (Anura, Ranidae, Petropedetinae), Rafael O. De Sá, Alan Channing

Biology Faculty Publications

The puddle frog genus Phrynobatrachus Günther, 1862 comprises about 64 currently recognized species (Frost, 1985). Of these, only the tadpoles of P. natalensis (Smith, 1849) (Power, 1927; Channing, 2001), P. guineensis Guibé & Lamotte, 1961(Rödel,1998) and P. alticola Guibé & Lamotte, 1961 (Rödel & Ernst, 2002) have been described. Phrynobatrachus mababiensis FitzSimons, 1932 (Dwarf Puddle frog, Wager, 1986; Mababe River frog, Frank & Ramus, 1996) is a small frog that usually calls from low in thick vegetation on flooded terrains close to the water. Very little has been published about the biology of this species. Passmore & Carruthers (1979) reported …


Leptodactylus Mystacinus, M. M. Heyer, W. R. Heyer, Rafael O. De Sá Jan 2003

Leptodactylus Mystacinus, M. M. Heyer, W. R. Heyer, Rafael O. De Sá

Biology Faculty Publications

Adult Leptodactylus mystacinus are of moderate size, the head is as wide as long, and the hind limbs are moderately short (see Table; Heyer and Thompson 2000 provided definitions of adult size and leg length categories for Leptodactylus). Male vocal sacs are not visible externally or at best are weakly expanded laterally and slightly darker than female throats. Male snouts are more spatulate than those of females. Male forearms are not hypertrophied. Males lack asperities on the thumbs and chest. One or two pairs of dorsolateral folds (indicated by dark/light outlining in indifferently preserved specimens) are present: one …


Taxonomy And Distribution Of Butterflies (Papilionoidea) Of The Skardu Region, Pakistan, Muhammad Abbas, Muhammad Ather Rafi, Mian Inayatullah, Muhammad Rafique Khan, Harry Pavulaan Dec 2002

Taxonomy And Distribution Of Butterflies (Papilionoidea) Of The Skardu Region, Pakistan, Muhammad Abbas, Muhammad Ather Rafi, Mian Inayatullah, Muhammad Rafique Khan, Harry Pavulaan

The Taxonomic Report of the International Lepidoptera Survey

A study was conducted in six different localities around Skardu, Pakistan to document the butterfly fauna of that region. The study revealed that 16 species in 5 families and 14 genera occur in the area. The families include: Papilionidae (represented only by the genus Parnassius); Pieridae (genera Pieris, Pontia, and Colias are represented); Lycaenidae (genera Lycaena, Everes, Aricia, Plebejus, Zizeeria, and Zizina are represented); Nymphalidae (only two genera, Aglais and Cynthia are represented); and Satyridae (represented by the genera Pararge and Maniola).


A Review Of Poanes Hobomok (Hesperiidae: Hesperiinae), With The Description Of A New Subspecies From The Southern Appalachians, Ronald R. Gatrelle Nov 2002

A Review Of Poanes Hobomok (Hesperiidae: Hesperiinae), With The Description Of A New Subspecies From The Southern Appalachians, Ronald R. Gatrelle

The Taxonomic Report of the International Lepidoptera Survey

Poanes hobomok monofacies is described from the southern limits of the Appalachian Mountains in western North Carolina, northern Georgia and eastern Tennessee, United States. The type locality is Chestnut Mountain, 3,400’, Macon County, North Carolina, United States. This new subspecies is characterized by the similarity of males and females and overall much darker and subdued marking when compared to both P. h. hobomok (eastern to mid-, northern United States and eastern to mid-, southern Canada) and P. h. wetona (Colorado and New Mexico, United States). The northern and western range of this new taxon and the …


Recruitment Variability Of Atlantic Croaker, Micropogonia Undulatus, With Observations On Environmental Factors, Sumalee Hoskin Oct 2002

Recruitment Variability Of Atlantic Croaker, Micropogonia Undulatus, With Observations On Environmental Factors, Sumalee Hoskin

Biological Sciences Theses & Dissertations

I examined entrance patterns of Atlantic croaker, Micropogonias undulatus by comparing the abundance, length, age and growth rates, of larvae as they entered Oregon and Ocracoke Inlets, NC. These biological factors were then compared against environmental factors to assess the influence the physical environment has on recruitment variability. Entrance abundance into Oregon Inlet was an order of magnitude higher than abundance into Ocracoke Inlet. However, the difference was influenced by three peak events in Oregon Inlet and non-parametric tests found no difference in median abundance between the two inlets. Mean standard length was smaller at Oregon Inlet than Ocracoke Inlet …


Benthic Biological Monitoring Program Of The Elizabeth River Watershed (2001) With A Study Of Paradise Creek, Daniel M. Dauer Oct 2002

Benthic Biological Monitoring Program Of The Elizabeth River Watershed (2001) With A Study Of Paradise Creek, Daniel M. Dauer

Elizabeth River Reports

Executive Summary

A study of the macrobenthic communities of the Elizabeth River watershed was initiated in summer 1999. This report presents the data from the third year of sampling in 2001. The three objectives of the Benthic Biological Monitoring Program of the Elizabeth River watershed are: (1) To characterize the health of the tidal waters of the Elizabeth River watershed as indicated by the structure of the benthic communities. ( 2) To conduct trend analyses on long-term data at 14 fixed-point stations to relate temporal trends in the benthic communities to changes in water and/or sediment quality. Trend analyses will …


The Tadpole Of Proceratophrys Avelinoi (Anura: Leptodactylidae), Rafael O. De Sá, José A. Langone Sep 2002

The Tadpole Of Proceratophrys Avelinoi (Anura: Leptodactylidae), Rafael O. De Sá, José A. Langone

Biology Faculty Publications

The genus Proceratoprhys is poorly known. It consists of 14 currently recognized species (Frost, 2000) of medium-sized frogs distributed from northeastern Argentina and Paraguay to southeast Amazonia (Rondonia State), eastern and southern Brazil Proceratophrys avelinoi was described from Misiones, Argentina (Mercadal de Barrio and Barrio, 1993). The larval stage of this species is unknown. Herein, we describe the tadpole and the characteristics of the internal oral anatomy of P. avelinoi using scanning electron microscopy (SEM).


Pterourus Appalachiensis (Papilionidae: Papilioninae), A New Swallowtail Butterfly From The Appalachian Region Of The United States, Harry Pavulaan, David M. Wright Jun 2002

Pterourus Appalachiensis (Papilionidae: Papilioninae), A New Swallowtail Butterfly From The Appalachian Region Of The United States, Harry Pavulaan, David M. Wright

The Taxonomic Report of the International Lepidoptera Survey

A new univoltine species of Tiger Swallowtail, Pterourus appalachiensis, is described from the southern Appalachian Mountain region of the eastern United States. This distinct swallowtail has remained unrecognized by lepidopterists since the description of its sympatric congener Pterourus glaucus (Linnaeus) in 1758. Historical accounts of Tiger Swallowtails from this region pertain specifically to glaucus and cannot be attributed to this new species. Morphology, voltinism, phenology, distribution, and behavioral traits indicate species level status of appalachiensis. Although appalachiensis shares several phenotypic characters with the recently elevated species canadensis (Rothschild & Jordan), preliminary mitochondrial DNA analysis indicates that appalachiensis is …


The Diversity And Abundance Of Parasites In Age Groups Of Yellow Perch In Lake Bemidji, Mn Applied To A Whittaker Curve, Kelly J. Main May 2002

The Diversity And Abundance Of Parasites In Age Groups Of Yellow Perch In Lake Bemidji, Mn Applied To A Whittaker Curve, Kelly J. Main

Honors Capstones

Capstone submitted as a graduation requirement for the BSU Honors Program.


Name-Bearing Types And Taxonomic Synopsis Of Three Lycaenid Butterfly Taxa From Western Canada (Lepidoptera: Lycaenidae), Norbert G. Kondla, Crispin S. Guppy May 2002

Name-Bearing Types And Taxonomic Synopsis Of Three Lycaenid Butterfly Taxa From Western Canada (Lepidoptera: Lycaenidae), Norbert G. Kondla, Crispin S. Guppy

The Taxonomic Report of the International Lepidoptera Survey

We clarify which of two designated lectotypes of Chrysophanus florus Edwards, 1884 is valid. We also show that the putative holotype of Plebeius saepiolus insulanus Blackmore, 1920 is actually a lectotype. A valid neotype designation for Lycaena saepiolus amica Edwards, 1863 is provided. Publication dates are corrected and we also briefly review the various taxonomic interpretations and distributions that appear in the literature with respect to these taxa.


Ecology Of The Missouri River. Progress Report, Dingell-Johnson Project F-75-R-19, Supplement 1- Missouri River Creel Survey, Camp Creek To Kansas State Line, 31 March Through 12 October 2001, Gerald Mestl May 2002

Ecology Of The Missouri River. Progress Report, Dingell-Johnson Project F-75-R-19, Supplement 1- Missouri River Creel Survey, Camp Creek To Kansas State Line, 31 March Through 12 October 2001, Gerald Mestl

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

This report describes Missouri River activities and results related to a channelized Missouri River creel survey conducted from 31 March through 12 October 2001. This is the second of a planned annual creel survey to be conducted on alternating sections of the channelized Missouri River to measure changes in recreational fishing activity, especially those changes due to large scale habitat restoration efforts. Future reports will contain additional analyses of these data. Anglers spent over 22,000 hours fishing the Missouri River from Camp Creek (rkm 883.5) to the Kansas state line (rkm 790.2) during the survey period. Effort peaked during the …


Fisheries Management Report No. 6 - Proceedings Of Marron Farming Open Day 2002, Greg B. Maguire Apr 2002

Fisheries Management Report No. 6 - Proceedings Of Marron Farming Open Day 2002, Greg B. Maguire

Fisheries Published Reports

The marron industry is of considerable importance to the Department of Fisheries, being one of the older aquaculture industries in Western Australia, and one that accounts for around half the aquaculture licence holders in the State. While it has not grown as quickly as many hoped in the past, in 2000/01, some 52.2 tonnes of marron were produced, worth $1.18 million at the farm gate.

It is regionally significant, particularly in the south-west, and depending on appropriate site selection, has considerable potential in other areas. Farms are distributed from near Geraldton to around Bremer Bay, with additional interest around Esperance. …


Development Of Diagnostic Approaches To Determine Sources Of Anthropogenic Stress Affecting Benthic Community Conditions In The Chesapeake Bay, Daniel M. Dauer, Michael F. Lane, Roberto J. Llansó Apr 2002

Development Of Diagnostic Approaches To Determine Sources Of Anthropogenic Stress Affecting Benthic Community Conditions In The Chesapeake Bay, Daniel M. Dauer, Michael F. Lane, Roberto J. Llansó

Benthic Applications

Benthic macrofauna are an important component of estuarine ecosystems. These organisms are a food source for higher trophic levels including fishes and crabs (Virnstein 1977, 1979; Holland et al. 1980; Dauer et al. 1982) and birds (Botton 1984; Quammen 1984). Benthic macrofauna affect both the physical and chemical properties of the sediment and the overlying water column (e.g., Rhoads and Young 1970; Rhoads 1973; Aller 1978, 1980), influence nutrient cycling (Rowe et al 1975; Zeiteschel 1980; Flint and Kamykowski 1984), and are capable of directly controlling phytoplankton biomass in the water column (Cleorn 1982; Officer et al 1982; Cohen et …


Leptodactylus Silvanimbus, W. R. Heyer, Rafael O. De Sá, Sarah Muller Jan 2002

Leptodactylus Silvanimbus, W. R. Heyer, Rafael O. De Sá, Sarah Muller

Biology Faculty Publications

Adult Leptodactylus silvanimhus are of moderate sized, the head is about as wide as long, and the hind limbs are moderate in length (see Table; also see Heyer and Thompson 2000 for definitions of adult size and leg length categories for Leptodacrylus). The male vocal sac is single and internal. Male forearms are hypertrophied in larger individuals. Adult males have two black thumb spines on each hand and lack chest spines. Individuals lack dorsolateral folds. The toe tips are narrow, not expanded. Females have weakly developed lateral toe fringes and males either have lateral toe ridges or weakly developed fringes. …


Initial Survey Of The Butterflies And Skippers In The Vicinity Of The Buck Creek Serpentine Barrens, Clay County, North Carolina, Ronald R. Gatrelle Dec 2001

Initial Survey Of The Butterflies And Skippers In The Vicinity Of The Buck Creek Serpentine Barrens, Clay County, North Carolina, Ronald R. Gatrelle

The Taxonomic Report of the International Lepidoptera Survey

Summary

General. Serpentine barrens are generally low in biotic diversity. However, these barrens are known to frequently harbor unusual species of plants and animals not usually found elsewhere. A survey was conducted from May 4 through October 2, 2001 in and around the Buck Creek Barrens located in Clay County, North Carolina, United States to document the butterfly and skipper taxa present at this location and their status. The site was visited 15 times during this period with at least two visits each month except September and October. A total of 76 different taxa were located with another 14 …


Nebraska And South Dakota 2000 Missouri River Recreational Use Survey: Supplement Ii, Nebraska And South Dakota 2000 Missouri River Recreational Use Survey, Fort Randall Tailwater To Big Sioux River, Gerald Mestl, Gerald Wickstrom, Clifton Stone Oct 2001

Nebraska And South Dakota 2000 Missouri River Recreational Use Survey: Supplement Ii, Nebraska And South Dakota 2000 Missouri River Recreational Use Survey, Fort Randall Tailwater To Big Sioux River, Gerald Mestl, Gerald Wickstrom, Clifton Stone

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

The 2000 Missouri River recreational use survey ran 1 April 2000 through 31 December 2000 and covered the Fort Randall Dam to Big Sioux River reach. Recreational user data was collected from postage paid post cards left on vehicles and through personal interviews. Pressure data was collected during a roving survey from ground counts of vehicles, boat trailers, recreational users. Aerial counts were made to compare angling and recreational boating data with ground count data. Recreational users spent an estimated 745,303 hours on the Missouri River survey reach during 2000. Fishing accounted for an estimated 458,749 hours, or 62% of …


An Examination Of The Mitoura (Lycaenidae) In The Southeastern United States: With The Description Of A New Subspecies Of Mitoura Hesseli, Ronald R. Gatrelle Aug 2001

An Examination Of The Mitoura (Lycaenidae) In The Southeastern United States: With The Description Of A New Subspecies Of Mitoura Hesseli, Ronald R. Gatrelle

The Taxonomic Report of the International Lepidoptera Survey

Four subspecies of Mitoura grynea occur in the United States east of the Mississippi River. The nominate subspecies occupies this entire area except for Florida and the coastal regions of South Carolina and Georgia. Mitoura g. grynea is usually associated with Juniperus virginiana. A neotype is designated for Lycus gryneus from Aiken County, South Carolina. Mitoura grynea smilacis is endemic to the southeastern coastal islands and coastal mainland from about Brunswick Georgia north to the Santee River delta of South Carolina. Smilacis’ range corresponds to that of Juniperus silicicola in that area. A neotype is designated for …


An Examination Of Southeastern U. S. Satyrium (Lycaenidae: Theclinae), Part Two: The Identification And Delimitation Of Nominate Satyrium Liparops And The Description Of A New Subspecies From West Central Peninsular Florida, Ronald R. Gatrelle Aug 2001

An Examination Of Southeastern U. S. Satyrium (Lycaenidae: Theclinae), Part Two: The Identification And Delimitation Of Nominate Satyrium Liparops And The Description Of A New Subspecies From West Central Peninsular Florida, Ronald R. Gatrelle

The Taxonomic Report of the International Lepidoptera Survey

The name Satyrium liparops liparops has traditionally been applied to all liparops populations from eastern Georgia southward. This tradition is shown to be in error. The type locality of nominate liparops is restricted by original description to Screven County, Georgia. A neotype is designated from Screven County and deposited in the Museum of the Hemispheres (MOTH) collection Goose Creek, South Carolina. The range of nominate liparops is projected to be from coastal South Carolina across the far southern United States (including the Florida panhandle) and into Texas. The population in west central peninsular Florida is described as new subspecies S …


Benthic Biological Monitoring Program Of The Elizabeth River Watershed (2000), Daniel M. Dauer Jul 2001

Benthic Biological Monitoring Program Of The Elizabeth River Watershed (2000), Daniel M. Dauer

Elizabeth River Reports

Executive Summary

A study of the macrobenthic communities of the Elizabeth River watershed was initiated in summer 1999. This report presents the data from the second year of sampling in 2000. The three objectives of the Benthic Biological Monitoring Program of the Elizabeth River watershed are: (1) To characterize the health of the tidal waters of the Elizabeth River watershed as indicated by the structure of the benthic communities. ( 2) To conduct trend analyses on long-term data at 14 fixed-point stations to relate temporal trends in the benthic communities to changes in water and/or sediment quality. Trend analyses will …


An Examination Of Southeastern U.S. Satyrium (Lycaenidae: Theclinae), Part One: An Obscure New Subspecies Of Satyrium Edwardsii, Ronald R. Gatrelle Jun 2001

An Examination Of Southeastern U.S. Satyrium (Lycaenidae: Theclinae), Part One: An Obscure New Subspecies Of Satyrium Edwardsii, Ronald R. Gatrelle

The Taxonomic Report of the International Lepidoptera Survey

Satyrium edwardsii meridionale is described as a new subspecies from Aiken County, South Carolina, United States. This scarce colony is the southeasternmost known population of this butterfly in the United States. It was discovered by the author (Ronald R. Gatrelle) in 1990 near Aiken State Park in Aiken County, South Carolina. This site is in South Carolina’s upper Coastal Plain in the southern part of the state adjacent to Georgia. It is known from only one male and one female at the type locality. Because it was known from only one pair, the author thought it best to wait until …


Clarification Of And Comments On Northern Speyeria Hydaspe Subspecies (Lepidoptera: Nymphalidae), Norbert G. Kondla May 2001

Clarification Of And Comments On Northern Speyeria Hydaspe Subspecies (Lepidoptera: Nymphalidae), Norbert G. Kondla

The Taxonomic Report of the International Lepidoptera Survey

The geographic distribution and use of three northern Speyeria hydaspe subspecies names is reviewed. This is necessary due to literature errors about the type locality of subspecies rhodope (Edwards, 1874). The correct placement of the rhodope type locality renders the name S. hydaspe sakuntala (Skinner, 1911) of interior British Columbia as a junior synonym of S. hydaspe rhodope. The name S. hydaspe minor (McDunnough, 1927) is available for the coastal populations by those who recognize these as different from those of the interior.


A Common Pattern Of Somite Cell Rotation In Three Species Of Pipidae, Shou-Yuan Fan, Rafael O. De Sá, Gary P. Radice Mar 2001

A Common Pattern Of Somite Cell Rotation In Three Species Of Pipidae, Shou-Yuan Fan, Rafael O. De Sá, Gary P. Radice

Biology Faculty Publications

During amphibian somitogenesis, presumptive myotome cells change shape from round or polygonal to elongated and aligned parallel to the notochord (for reviews see Radice, et al., 1989; Keller, 2000). Although the final orientation of myotomal cells is always axial, the movements that achieve this final arrangement can differ greatly between species. The simplest movement is that seen in Bombina variegata, Pelobates fuscus, and Bufo bufo (Brustis et al., 1976; Brustis, 1979; Kielbowna, 1981 ). In these anurans, after segmentation myotomal cells simply elongate along the embryo’s anteroposterior axis. The urodeles Ambystoma mexicanum and Pleurodeles waltl have a very different pattern; …


Natural Succession Of Benthic Populations In Constructed Sediment Ponds And Ditches In Southwestern West Virginia, Robin E. Dolin Jan 2001

Natural Succession Of Benthic Populations In Constructed Sediment Ponds And Ditches In Southwestern West Virginia, Robin E. Dolin

Theses, Dissertations and Capstones

Strip mining causes major disturbances of the natural environment. One such disturbance is the creation of valley fills, which often fill in the headwaters of small streams. Runoff from these valley fills can cause heavy siltation as well as acid and heavy metal deposition downstream. One way to combat this problem is through the construction of sedimentation ponds, which slow down the flow of water so that sediment can settle out and water chemistry can be altered before the water is discharged into the stream. Since these ponds are, in effect, temporarily replacing small headwaters once present, the question is …


Factors Influencing Spatial Variability In Soil Nitrogen (N) Dynamics In N-Treated And Untreated Watersheds Of The Fernow Experimental Forest, West Virginia, Nikki Lenore Lyttle Jan 2001

Factors Influencing Spatial Variability In Soil Nitrogen (N) Dynamics In N-Treated And Untreated Watersheds Of The Fernow Experimental Forest, West Virginia, Nikki Lenore Lyttle

Theses, Dissertations and Capstones

The central Appalachian region of the United States receives some of the highest inputs of nitrogen (N) due to acidic deposition in the nation. It is believed that these high could levels contribute to a decline in forest soils within the next 50 to 70 yrs. This study examines factors that influence spatial variability in N-treated and untreated watersheds of the Fernow Experimental Forest, Parsons, West Virginia. Within each of the two watersheds [WS4 untreated control, > 100 yr.; WS3 N-treated, acidified, clear cut, ~ 31 yr.], two 0.04 ha plots, one high N and one low N, were selected for …


The Gray Wolves (Canis Lupus) Of British Columbia’S Coastal Rainforests, Chris T. Darimont, Paul C. Paquet Jan 2001

The Gray Wolves (Canis Lupus) Of British Columbia’S Coastal Rainforests, Chris T. Darimont, Paul C. Paquet

Biogeography and Ecological Opportunity Collection

The mainland coast of British Columbia (BC) is a remote area that is comparatively free from human-caused disturbance. However, concerns about current and anticipated increases in industrial forestry activity have prompted conservation biologists to investigate the biota in this understudied region. We were commissioned by the Raincoast Conservation Society to study coastal wolves so that information could be incorporated into ongoing conservation planning and education efforts. The summer of 2000 marked the pilot season of a multi-year research project. Our team spent more than 240 person days in the field during the summer and fall seasons. We surveyed 18 mainland …


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 …


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 …


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% …