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Full-Text Articles in Physical Sciences and Mathematics

Estimate Of Production By A Population Of Fathead Minnows, Pimpephales Promelas, In A South Dakota Prairie Wetland, Ronald D. Payer Jan 1977

Estimate Of Production By A Population Of Fathead Minnows, Pimpephales Promelas, In A South Dakota Prairie Wetland, Ronald D. Payer

Electronic Theses and Dissertations

Estimates of production and population densities were obtained for an autochthonous population of fathead minnows, Pimephales promelas Rafinesque, in a South Dakota prairie wetland. The study was conducted from May to September of 1976. Population estimates were obtained using a Schnabel-type mark and recapture model. Fish were marked either by fin clipping or granular fluorescent pigments driven into the dermal tissue. Production estimates were derived both arithmetically and graphically. The estimated population of adult fathead minnows declined from 194 in May and June to 26 in July. Production by adults was estimated at 0.10 kg, or 0.0007 gm/m²/yr. The population …

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Digestibility Of Common Forage Plants And Energetic Requirements Of The Black-Tailed Prairie Dog, Maureen A. Beckstead Jan 1977

Digestibility Of Common Forage Plants And Energetic Requirements Of The Black-Tailed Prairie Dog, Maureen A. Beckstead

Electronic Theses and Dissertations

Black-tailed prairie dogs (Cynomys ludovicianus) assimilated 51.5 percent of the wheatgrass (Agropyron intermedium) they consumed; thus, they would have to consume 0.148 kcal · g-1 · day-l in order to obtain the 0.076 kcal · g-1 · day-1 they would require to maintain their weight. Prairie dogs assimilated 31.5 percent of the buffalograss/blue grama mixture (Buchloe dactyloides/Bouteloua gracilis) they were fed. They would have to consume 0.229 kcal · g-1 · day-1 of this forage to assimilate 0.072 kcal · g-1 · day-1 and maintain their weight. The proximate composition of forages fed in feeding trials was similar to that …

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Wildlife Habitat Evaluation Of The Unchannelized Missouri River In South Dakota, James R. Clapp Jan 1977

Wildlife Habitat Evaluation Of The Unchannelized Missouri River In South Dakota, James R. Clapp

Electronic Theses and Dissertations

Areas of eight habitats were identified, delineated, and measured along the unchannelized Missouri River in South Dakota. Agricultural and urban developments existed on 60 percent of the land within 1 km of the river. Six habitat types made up the non-developed land in the study area: cottonwood-dogwood (16 percent), cottonwood-willow (9 percent), elm-oak (7 percent), cattail marsh (3 percent), sand dune (3 percent), and sand bar (1 percent). All non-developed habitats except sand bar were sampled to obtain vegetative composition and to determine their value to wildlife. The value of each habitat to nine faunal groups of wildlife was subjectively …

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Biology Of The Porcupine (Erethizon Dorsatum) In Northwestern South Dakota, Judith Johnson Jan 1977

Biology Of The Porcupine (Erethizon Dorsatum) In Northwestern South Dakota, Judith Johnson

Electronic Theses and Dissertations

The summer home ranges, food habits, cover preferences, population dynamics, metabolic rates, growth rates, and taxonomic characteristics were determined for porcupines (Erethizon dorsatum) in northwestern South Dakota. The summer home ranges were 158.2 ha for adult females, 90.4 ha for juveniles, and 57.9 ha for adult males. The population was 34 percent adult males, 16 percent juvenile males, 34 percent adult females, and 15 percent juvenile females. The preferred daytime cover choice was silver buffaloberry (Shepherdia argentea), followed by snowberry (Symphoricarpos occidentalis), earth dens, forbs, and low brush. Shrubs were the most important item in the diet, then trees, forbs, …

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Food, Growth, And Reproduction Of White Crappies (Pomixis Annularis) And Black Crappies (P. Nigromaculatus) In Lake Poinsett, South Dakota, Thomas R. Busiahn Jan 1977

Food, Growth, And Reproduction Of White Crappies (Pomixis Annularis) And Black Crappies (P. Nigromaculatus) In Lake Poinsett, South Dakota, Thomas R. Busiahn

Electronic Theses and Dissertations

The food habits, food selectivity, growth, condition, and population structures of the white crappies (Pomoxis annularis) and black crappies (P. nigromaculatus) in Lake Poinsett, South Dakota, were studied from May, 1975, to May, 1976. The total food volume of 173 adult white crappies consisted of 59.0% plankton1o crustaceans, 25.2 % insects, 14.5 % fish, and 1.3 % miscellaneous organisms. The food volume of 39 adult black crappies consisted of 39.0 % planktonic crustaceans, 3.5 % insects, 57.8 % fish, and 0.7 % miscellaneous organisms. Both species selected Daphnia pulex over other zooplankton and probably contributed to its decline from 193.8/l …

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Use Of Stockpods For Nesting By Giant Canada Geese, Paul M. Bultsma Jan 1976

Use Of Stockpods For Nesting By Giant Canada Geese, Paul M. Bultsma

Electronic Theses and Dissertations

A study of giant Canada geese (Branta canadensis maxima) nesting on stockponds in western South Dakota was conducted during 1974 and 1975. Analysis of 10 selected variables at nests on natural sites indicated that distance of water below high water level and percent slope from wetland to horizon, contributed the most to the use of the site. Distance from wetland to horizon and disturbance factors were two important variables measured to determine use of artificial nesting structures. First nests were initiated on 1 April 1974 and 8 April 1975. Twenty-five nests (16 percent) were located on artificial nesting structures, and …

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The Aquatic Ecology Of Two Seasonal Marshes In Eastern South Dakota, Walter K. Donaldson Jan 1976

The Aquatic Ecology Of Two Seasonal Marshes In Eastern South Dakota, Walter K. Donaldson

Electronic Theses and Dissertations

Zooplankton, benthos, nekton, aufwuchs, and the physical-chemical limnology of two seasonal marshes in eastern South Dakota were monitored from April-June 1975. Bothwell and Lund Marshes contained water from 15 April-July 1975. The dominant i. ons, Ca ++, Mg+ +, and sulfate, made the water hardness non-carbonate. Floating vegetation, Lemna trisulca and Cladophora sp., became abundant in both marshes during the first week of June, and formed large thick mats by the end of June 1975. Daphnia pulex was the dominant zooplankter in Bothwell Marsh and made up 33% of the zooplankton density during the 1975 season. The population was triacmic, …

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Analysis Of Aerial Surveys And Tolerance Of Landowners For A Canada Goose Flock In Northeastern South Dakota, Thomas C. Tacha Jan 1976

Analysis Of Aerial Surveys And Tolerance Of Landowners For A Canada Goose Flock In Northeastern South Dakota, Thomas C. Tacha

Electronic Theses and Dissertations

Four hundred rural landowners were interviewed in Day and Marshall counties in South Dakota in 1974 and 1975. These 400 interviews included 200 interviews with landowners living within 6.4 km of the three major summer-fall goose concentration areas and 200 interviews from a random sample of landowners living in the study area. Eighty-six percent of the interviewed landowners indicated that it was a good idea to expand the northeastern South Dakota Canada goose flock from 2,000 to 5,000 birds. Only 6 percent of the landowners had complaints about the geese, despite the fact that 23.5 percent of them had received …

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An Evaluation Of The Fishery Resource In A Portion Of The James River, South Dakota Scheduled For Channel Modification, Dennis Tol Jan 1976

An Evaluation Of The Fishery Resource In A Portion Of The James River, South Dakota Scheduled For Channel Modification, Dennis Tol

Electronic Theses and Dissertations

The fish populations of a 193 km (120 mi) section of the James River between Tacoma Park and Redfield, South Dakota that is scheduled for stream modification under the Oahe Irrigation project were evaluated from October 74 to July 76. Twenty-two species of fish were captured in the James River between Tacoma Park and Redfield, South Dakota. The fishes use the area primarily as a spawning ground and nursery for young-of-the-year. Evidence of spawning was found for 19 species of fish. Only a residual population of forage fishes, young-of-the-year of various species, and a few adult black bullheads attempt to …

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Productivity Of A Resident Giant Canada Goose Flock In Northeastern South Dakota, J. David Hilley Jan 1976

Productivity Of A Resident Giant Canada Goose Flock In Northeastern South Dakota, J. David Hilley

Electronic Theses and Dissertations

. A 2-year study (1974-1975) of a resident Canada goose (Branta canadensis maxima) flock is reported. Twenty-four percent of the artificial nest structures (ANS) available were used by nesting geese. Artificial nesting structures, islands, muskrat houses and peninsulas were used by geese as nesting sites. Mean clutch size of completed nests was 5.14 in 1974 and 5.26 in 1975. Mean clutch size was 5.38 on ANS and 4.89 on NNS for the 2-year study. At least one egg hatched in 87 percent of the 283 nests located during the study. Larger clutches had a higher hatchability. Nest success was greater …

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Sharp-Tailed Grouse Nesting And Brooding Habitat In Southwestern North Dakota, Stanley C. Kohn Jan 1976

Sharp-Tailed Grouse Nesting And Brooding Habitat In Southwestern North Dakota, Stanley C. Kohn

Electronic Theses and Dissertations

The habitat of nesting and brooding sharp-tailed grouse (Pedioecetes phasianellus) was studied 1 April to 25 August 1973 and 1974. The objective of the study was to determine the quality and quantity of vegetation at nest and brood locations of sharp-tailed grouse in relation to available vegetation within pastures. Five range sites, lowland draw, rolling grassland, upland grassland, rocky outcropping, and claypan were studied. Thirty-four females were trapped on dancing grounds and equipped with radio transmitters. Seventeen nests were located by monitoring the movements of transmitter-equipped hens and 26 nests were located through use of cable-chain drag. Height of vegetation …

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Factors Influencing Habitat Use By Breeding Waterfowl In South Dakota, Michael R. Mcenroe Jan 1976

Factors Influencing Habitat Use By Breeding Waterfowl In South Dakota, Michael R. Mcenroe

Electronic Theses and Dissertations

Wetland characteristics, adjacent upland conditions, and corresponding waterfowl populations were surveyed on 500 quarter sections in 125 clusters proportionally stratified within eight physiographic strata in South Dakota. Two survey were conducted, one in May and a second in June, each year during 1973 and 1974. Habitat variables of each wetland and of each quarter section, respectively, were analyzed for each species of waterfowl through multiple regression analysis. Multiple regression equations had highest coefficients of determination for mallards (Anas platyrhynchos), pintails (Anas acuta), blue-winged teal (Anas discors), and gadwall (Anas strepera). Coefficient of determination for these species were greatest in the …

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Distribution, Age, And Growth, And Feeding Ecology Of Paddlefish (Polyodon Spathula) In Unaltered Missouri River, South Dakota, Rudolph S. Rosen Jan 1976

Distribution, Age, And Growth, And Feeding Ecology Of Paddlefish (Polyodon Spathula) In Unaltered Missouri River, South Dakota, Rudolph S. Rosen

Electronic Theses and Dissertations

Four hundred eighty-four paddlefish (Polyodon spathula) were captured 26 June 1975 to 11 August 1976 from an unaltered stretch of Missouri River in South Dakota. Vital statistics were measured on all fish, 171 were sacrificed during the analysis of food habits, and 301 fish were tagged and released. Paddlefish were located by observation, gill netting, and snagging. Paddlefish were primarily found downstream from submerged sandbars from late spring to early fall. The crests of the sandbars were 0.1 to 1.0 m deep and immediately downstream, the depth was 1.5 to 4.5 m, and the current velocity was 0 to 0.3 …

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Key To Microscopic Fragments Of Plant Tissue In Prairie Dog Stomachs And Food Habits Of Prairie Dogs In South Dakota, Carol A. Summers Jan 1976

Key To Microscopic Fragments Of Plant Tissue In Prairie Dog Stomachs And Food Habits Of Prairie Dogs In South Dakota, Carol A. Summers

Electronic Theses and Dissertations

The purpose of this study was to (1) develop a reference collection and construct a key of plants occurring on prairie dog towns in southwest South Dakota; (2) determine plant species eaten by prairie dogs by analyzing stomach and pellet samples; and (3) relate the availability of plant species and preference in the feeding habits of prairie dogs. Two prairie dog towns of different vegetation were studied. Four burrows in each of two vegetative types for each town were randomly selected. Prairie dogs and pellet samples were collected from these burrows; plant cover was measured in four concentric circles for …

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Effects Of P.L. 566 Stream Channelization On Wetlands In The Prairie Pothole Region, Ronald E. Erickson Jan 1976

Effects Of P.L. 566 Stream Channelization On Wetlands In The Prairie Pothole Region, Ronald E. Erickson

Electronic Theses and Dissertations

The Wild Rice Creek Watershed project, in North and South Dakota was constructed under authority of the Small Watershed Protection and Flood Prevention Act (P.L. 83-566 as amended). Structural measures included 24.7 miles of channelization and four floodwater retarding dams. To measure the degree that channelization influenced drainage of prairie wetlands, drainage rates in a channelized tributary were compared to rates in an unchannelized tributary of Wild Rice Creek. Channelization had a direct impact on wetlands by channel drainage reduction of overbank flows, and by providing drainage outlets. Indirect (secondary) wetland losses are believed to have occurred outside of the …

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Population Status Of Beaver On The Free-Running Missouri River In Southeastern South Dakota, Robert J. Vanden Berge Jan 1976

Population Status Of Beaver On The Free-Running Missouri River In Southeastern South Dakota, Robert J. Vanden Berge

Electronic Theses and Dissertations

One hundred sixty two beaver (Castor canadensis) harvested by trappers from the free-running Missouri River in southeastern South Dakota were examined from fall 1974 to spring 1976. Ninety two were males and 70 were females (131:100 sex ratio). Age specific sex ratios were not significantly different (P >0.05) from a 1:1 ratio for all age classes. The age structure of the sample was 69:26:45:15:4:3 for age classes zero through five, respectively. Minimum breeding age for female beaver was 2.5 years. Seventy-eight percent of all females (>2.5 years old) collected after the breeding season contained corpora lutea and viable fetuses. …

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Effects Of Atrazine On Penned Pheasants And The Occurrence Of Stress Marks On Feathers, Thomas Orin Melius Jan 1975

Effects Of Atrazine On Penned Pheasants And The Occurrence Of Stress Marks On Feathers, Thomas Orin Melius

Electronic Theses and Dissertations

Doses of 4 g of atrazine (AAtrex) were not lethal to penned hen pheasants (Phasispus colchicus), but levels of 6, 8, 10 and 12 g induced mortality. Pen studies to determine the effects of atrazine on reproduction of hen pheasants were conducted with two replicates of the basic test. Birds were administered treatment levels of 0, 100, 200, or 400 mg of atrazine per hen per week. Egg production and gain in weight of hens were unaffected by the treatments. Replicate A eggs were unaffected by the treatments. Replicate A eggs were unaffected in shell thickness and pipping rates, while …

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Nesting Ecology Of The Ring-Necked Pheasant In Eastern South Dakota, Richard A. Olson Jan 1975

Nesting Ecology Of The Ring-Necked Pheasant In Eastern South Dakota, Richard A. Olson

Electronic Theses and Dissertations

Nesting of the ring-necked pheasant (Phasianus colchicus) was studied in 1973 and 1974 and 90 randomly chosen 4.05 – ha plots in the Lake Sinai Township of south-western Brookings County. Nest initiation and hatching peaks over the 2-year period occurred from 1-15 may and 16-30 June, respectively. Average density of nests was 0.3 per hectare in 1973 and 0.2 in 1974. Average clutch size for combined years was 8.6 for all nests and 10.8 for nests where clutches hatched. Clutch sizes declines as the nesting season progressed. Fertility of eggs in nests where clutches hatched was 96 percent. Hatching success …

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Food Habits Of Young-Of-The-Year Fishes In Abbey Pond, South Dakota, Randall D. Radant Jan 1975

Food Habits Of Young-Of-The-Year Fishes In Abbey Pond, South Dakota, Randall D. Radant

Electronic Theses and Dissertations

Food habits of young-of-the-year largemouth bass (Micropterus salmoides), bluegill (Lepomis macrochirus), black crappie (Pomoxis nigromaculatus), yellow bullhead (Ictalurus natalis), and yellow perch (Perca flavescens) were studied during 1973 and 1974 in Abbey Pond, South Dakota. Organisms found in young-of-the-year fish stomachs and in plankton samples were identified and counted in the laboratory. Zooplankton, aquatic insects and fish were the most important food organisms consumed by young fishes. Using Ivlev’s electivity index food electivity by the fishes for zooplankton was calculated. The size-specific food habits of young-of-the-year largemouth bass progressed from entomostracans to aquatic insects to fish. In most cases zooplanktons …

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Distribution And Importance Of Stockdams, Dugouts, And Natural Wetlands To Breeding Waterfowl In South Dakota, James J. Ruwaldt Jan 1975

Distribution And Importance Of Stockdams, Dugouts, And Natural Wetlands To Breeding Waterfowl In South Dakota, James J. Ruwaldt

Electronic Theses and Dissertations

Wetland distribution and utilization by breeding waterfowl of stockdams, dugouts, and natural wetlands were investigated in South Dakota during 1973 and 1974. Wetlands in South Dakota were estimated to encompass 590,499 ha and to total 631,557 basins. Natural ponds and lakes comprised 74.7 percent of the wetland area and 46.0 percent of the total number. Stockdams composed 13.9 percent of the wetland area and 14.0 percent of the number, and dugouts 0.3 percent and 8.1 percent of the state’s wetland area and number respectively. Ninety-one percent of the ponds and lakes were found east of the Missouri River and 86.7 …

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Results And Evaluation Of An Aerial Creel Survey Technique On Lake Sharpe, South Dakota, Bruce R. Schmidt Jan 1975

Results And Evaluation Of An Aerial Creel Survey Technique On Lake Sharpe, South Dakota, Bruce R. Schmidt

Electronic Theses and Dissertations

A creel survey, consisting of two independent surveys, was conducted on Lake Sharpe, South Dakota from May, 1973, through May, 1974. An aerial fisherman count was used to estimate fishing pressure and an angler interview survey was used to estimate catch rates, mean party size, mean fisherman day, and residence of the anglers. The results of the two surveys were combined to estimate harvest. The separate surveys were combined to estimate harvest. The separate surveys allowed optimum stratification and allocation of sampling effort for each. Estimated fishing pressure was 32,643 fisherman-hours, ±9.60% at the 95% confidence level, and the total …

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Tetrazoline Chemistry, Norman Wallace Rokke Jan 1975

Tetrazoline Chemistry, Norman Wallace Rokke

Electronic Theses and Dissertations

It was of interest to investigate the chemistry of some tetrazolines since they might be sources of heteroatomic analogues of trimethylenemethane. In addition, they might provide alternate means of synthesis of small ring compounds such as diaziridinones and diaziridineimines. New compounds which were prepared are 1-(2,6-dimethylphenyl)­ tetrazoline-5-one, 1-(2,6-dimethylphenyl)-4-methyltetrazoline-5-one, l-phenyl-4-methyl-5-iminotetrazoline, l-phenyl-4-methyl-5- methyliminotetrazoline, and l-phenyl-4-methyl-5-methyliminotetrazoline methiodide. The mass spectra of the tetrazolines investigated are characterized by ring fragmentations which are helpful in determining their structure. In addition, fragmentation represents one of the few examples of a retro-1,3-dipolar cycloaddition reaction initiated by electron impact. The monosubstituted tetrazolines are thermally unstable. The course of …

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Interactions Of Rhenium(V) Chloride And Oxotrichlorobis(Triphenlyphosphine)Rhenium(V) With Selected Solvents, Paul Luther Holm Jan 1975

Interactions Of Rhenium(V) Chloride And Oxotrichlorobis(Triphenlyphosphine)Rhenium(V) With Selected Solvents, Paul Luther Holm

Electronic Theses and Dissertations

The purpose of this study was to examine the solution interactions of rhenium(V) chloride and oxotrichlorobis(triphenylphosphine)rhenium(V) in a continuation of studies of rhenium(V) chemistry. These goals were accomplished using vacuum line and Schlenk tube techniques. As a result of this work, rhenium(V) chloride was found to dissolve with reaction in 1, 4-dioxane, diethyl ether and acetone. There was only a very small amount of rhenium(V) chloride which dissolved in carbon tetrachloride, chloroform and cyclohexane. Part of what did dissolve was shown by electronic and infrared spectroscopy to be oxotetrachlororhenium(VI) which was present as an impurity in small amounts. Oxotetrachlororhenium(VI) reacts …

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Nucleophilic Substitution At Phosphorus: Phosphate Thioesters, Ronnie L. Wilde Jan 1975

Nucleophilic Substitution At Phosphorus: Phosphate Thioesters, Ronnie L. Wilde

Electronic Theses and Dissertations

It was my objective to try to determine the mechanism of nucleophilic substitution at phosphorus in monothiophosphate triesters and to apply what I learn to the other phosphate systems. I also tried to obtain more data to show that the Lewis acid-base type complex through the phosphoryl oxygen is existent and does influence the reaction.

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Breeding Waterfowl Populations In South Dakota, Wayne G. Brewster Jan 1975

Breeding Waterfowl Populations In South Dakota, Wayne G. Brewster

Electronic Theses and Dissertations

Breeding waterfowl in South Dakota were censused on 500 legal quarter sections within 125 clusters representing a proportional stratified random sample of 0.16 percent of the state area. Two breeding pair counts, one in May and second in June, were conducted each year on the sample units in 1973 and 1974. Densities of total breeding pairs averaged 5.58 and 2.30 pairs per km2 in 1973 and 1974, respectively. Estimated populations based upon these densities were 1,067,500 breeding pairs in 1973 and 439,600 breeding pairs in 1974. The 58.8 percent decrease in the population occurred concurrently with intensification of drought conditions …

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Food Habits, Growth, And Production Of Young-Of-The-Year Walleyes, Stizostedion Vitreum Vitreum (Mitchell), In A South Dakota Pond, Ronne E. Walker Jan 1975

Food Habits, Growth, And Production Of Young-Of-The-Year Walleyes, Stizostedion Vitreum Vitreum (Mitchell), In A South Dakota Pond, Ronne E. Walker

Electronic Theses and Dissertations

A 12.45 hectare South Dakota pond was stocked with 25,000 walleye, Stizostedion vitreum vitreum (Mitichell), fingerling on 13 June, 1973. Walleyes were monitored for growth rate and food habits until 13 September, 1973. Walleyes were removed from the pond using various methods in order to evaluate the efficiency of removal methods. The average total length and average weight of walleyes in the pond increased from 43.5 mm and 0.50 g on 13 June to 167.1 mm and 41.25 g on 13 September. This was a gain of 123. 6 mm and 40.75 g or an average daily increase of 1.34 …

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Pheasant Reproduction And Survival As Related To Agricultural Fertilizer Use, Lawrence Francis Fredrickson Jan 1974

Pheasant Reproduction And Survival As Related To Agricultural Fertilizer Use, Lawrence Francis Fredrickson

Electronic Theses and Dissertations

Wing-clipped wild pheasants (Phasianus colchicus) were stocked in 1-acre and 0.5-acre pens having oat and bromegrass cover in 1972 and 1973 to test effects of fertilizer (Formulations: 34-0-0, 18-46-0, 0-46- 0, and 0-0-60) on pheasant reproduction and survival. One-half of the pens were fertilized with the recommended rate of pelleted fertilizer and the other half without fertilizer. Complete nest searches in July showed that nesting success was not significantly different (P>0.05) between treatments for both years. No significant difference (P>0.05) was found in clutch size or in number of ovulated follicles from control and experimental hens. Significantly more …

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Feeding Of Hatchery-Reared Brown Trout (Salmo Trutta L.) In Relation To The Diet In A South Dakota Stream, Richard W. Mccoy Jan 1974

Feeding Of Hatchery-Reared Brown Trout (Salmo Trutta L.) In Relation To The Diet In A South Dakota Stream, Richard W. Mccoy

Electronic Theses and Dissertations

One thousand five hundred catchable brown trout (17-26 cm) were stocked into the South Fork of the Yellowbank River May 17, 1973. Samples were taken one month apart from May 22, 1973, through October 29, 1973. Fifteen-minute drift samples were collected every hour for 24 hours and trout were captured every 4 hours. Trout captured ruing the study varied in condition ® from 1.34 to 2.55. Condition progressively decreased through August, rose in September, and decreased again by the October sample. The average weight of brown trout increased through the September sample and decreased in October. Two peaks in number …

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Studies Of The White Pelican In South Dakota: Reproductive Biology Of Wild Populations And Effects Of Polychlorinated Biphenyls And Ddt On The Behavior Of Penned Birds, Vernon Pat Mccrow Jan 1974

Studies Of The White Pelican In South Dakota: Reproductive Biology Of Wild Populations And Effects Of Polychlorinated Biphenyls And Ddt On The Behavior Of Penned Birds, Vernon Pat Mccrow

Electronic Theses and Dissertations

The learning behavior of penned white pelicans (Pelecanus erythrorhynchos) was studies 2 August to 5 October 1972 using a swimming pool – Y-maze apparatus in an operant conditioning experiment. The experiment consisted of three consecutive phases: trial-and-error learning, extinction, and relearning. Three groups of nine pelicans each were studied: a polychlorinated biphenyl (PCE) treated group, a DDT, DDD, DDE treated group, and a Control group. The object of this study was to determine the effect of PCB and DDT, DDD, DDE on the learning ability of penned white pelicans. Control, PCB, and DDT groups of penned white pelicans learned to …

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Habitat Preferences And Food Habits Of Striped Skunks In Eastern South Dakota, Melvin S. Moe Jan 1974

Habitat Preferences And Food Habits Of Striped Skunks In Eastern South Dakota, Melvin S. Moe

Electronic Theses and Dissertations

Habitat preferences of striped skunks (Mephitis mephitis) in Brookings County, South Dakota, were determined rom the relationship of nighttime roadside indices to 25 habitat variables of 277, 1-square mile plots. Winter tracking was also conducted. Skunks were collected on the study area in 1972-1972, and contents of 59 stomachs and 63 colons were studied to determine food habits. Indices of prey abundance in different habitat types were obtained from snap-trap surveys. The 25 variables accounted for 14.9 percent of the variation in skunk numbers. The relationships of three of these variables to skunk numbers were significant (P<0.05). The significant variables and the variation accounted for by each were: (a) number of areas of idle grassland, 6.3 percent; (b) number of rockplies, 1.5 percent; and (c) acreage of idle grassland, 1.3 percent. Idle grasslands were the main activity centers of skunks tracked during the winter. Food habits were analyzed for the periods March-April, May-June, July-August, and September-November. Insects were the most frequently found food item in al time periods except March-April, during which mammals occurred more frequently. Mammals made up the largest volume of food in March-April and May-June. Amphibians made up the greatest volume in July-August, while amphibians, mammals, and insects were found in nearly equal volumes in September-November. Bird remains occurred during all time periods. Eggs were found in May-June and July-August. Meadow voles (Microtus spp.), the most frequent mammalian food item during all time periods, were common only in habitat types having heavy residual cover. Idle grassland is an important nestling cover for gamebirds and waterfowl. Since the number of areas of this cover type apparently has a stronger relationship with skunk numbers than its total acreage, grassland nesting cover might best be managed in large, homogeneous blocks. Areas managed in this way would probably support lower skunk densities than more diverse areas containing equal acreages of idle grassland, thus reducing nest predation by skunks. Skunk control programs should be most efficient when centered around idle grassland and rockplies.

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