Document Type

Thesis - Open Access

Award Date

1966

Degree Name

Master of Science (MS)

Department

Wildlife Management

Abstract

Population distribution and mobility of deer were studied intensively along a 15-mile stretch of the Big Sioux River, and less intensively on an expanse of 1400 square miles in central eastern South Dakota. Objectives were to determine relative population numbers and distribution of deer, the extent of their daily and seasonal movements, and the principal factors influencing these populations and movements, and to test winter hard counts as a population index. Deer were captured in Clover traps or with a Cap-Chur gun and were marked individually with ear tags, ear streamers, and collars. Some deer were tracked by radio telemetry. Deer were most widely distributed during the summer. Ranges of many animals during this season were restricted o a few favored bedding and feeding sites, but some young animals wandered up to 20 miles. During the summer-fall transition, deer remained widely distributed but gathered in sloughs and thickets after cover in fields of corn and other crops was reduced by harvest. Fall ranges were restricted until the rut and hunting seasons scattered deer during November and December. Some herds started to form in early December but were broken up by hunters. Deer scattered until the end of the hunting seasons on December 31. In early January discrete herds of up to 80 animals began to form, but true yarding did not occur. Some herds wintered in fairly well-defined areas, but as much as 30 percent of the deer population remained widely scattered through the winter. Winter herds maintained fairly stable numbers, but some deer moved up to 12 miles between herds. Sloughs and wooded areas in draws or along stream bottoms with unused or washed out section-line roads creating 2- or 3-section blocks were favored as wintering areas. Some herds remained within these blocks, whereas other herds roamed over as much as 6 sections of land. Some wintering areas were used in more than one year. Herds generally remained distinct until the spring thaw. Some herds broke up immediately, but others broke up gradually. Animals moved out in several directions and at varying rates, but a definite predominance of northward movements along the Big Sioux River and its tributaries was noted. Cattle reduced the potential value of some areas as deer habitat. When cover conditions were optimum, as in summer, deer movemetns tended to be restricted. When cover was sparse, deer movements tended to be restricted. When cover was sparse, deer often traversed wide expanses of open fields between patches of heavy cover. During the fall, hunting influenced deer movements and distribution more than any other factor. The deer population in this study was partially migratory in that it used all of the study area for summer range but withdrew to a small part of it for the winter. The home range pattern of deer included one or more sub-areas which provided the total deer habitat requirements. When these requirements were disturbed, depleted, or changed, der moved to a new sub-area. Because of the nature of the habitat, movements between sub-areas were sometimes extensive and produced a multiple home range. Data from this study indicated that deer management units, if they could be administered effectively, might better be based on natural drainages than on counties as is now the case. Instability of winter herds ruled out the use of winter herd counts as an accurate population index. Since agricultural interests control the level at which deer populations may be maintained, a greater annual reduction in population size may soon be necessary to maintain deer at a level acceptable to farmers. Preserving natural vegetation and establishing artificial plantings that benefit other wildlife species will also benefit deer. 41. Introduction: Knowledge of the age of individuals comprising populations of fish is essential to the fishery biologist. From such information he is able to calculate the rate of growth, determine the age at which sexual maturity is attained and the longevity of the species. These calculations and determinations can be applied in the management of populations and in setting fishery regulations. There are numerous methods being used to determine the age of an individual fish. Of these, the scale method is the most important means of age determination being utilized with species of fish possessing scales (Cooper, 1951). This method assumes that the ratio of body length to scale length is constant for all sizes of fish. As the fish grows, the scale increases in size proportionally and lays down concentric ridges called circuli. If growth of the fish is uninterrupted, no change will occur in the growth pattern of the scale. However, in areas that experience seasonal changes in temperature, the rate of metabolism will decrease in this rate of growth during periods of cold weather. The decrease in the rate of growth results in a corresponding period of interrupted growth of the scale and is recognized by the spacing of the circuli. The circuli tend to be more widely spaced during the summer’s growth and more closely spaced during the winter’s growth. Another growth characteristic of the scale is that with a decrease in the growth rate the circuli will be interrupted and will end at different places along the lateral margin. Then, with the resumption of growth, the new ridges parallel the entire scale margin and hence out across the unfinished circuli previously formed. This phenomenon is called “cutting over” and is very useful in determining the yearmark or “annulus”. In the analysis of a scale for age determination of cutting over and the spacing of the circuli are utilized to locate the annulus. The age of the fish is then determined by counting the number of annuli. The first annulus is measured from the center (focus) of the scale to the outer margin of the first closely spaced circuli encountered and/or to where the cutting-over effects are observed. The other annuli present are measured form the outer margin of the previous year’s growth to the next outer margin where the annular characteristics are located. Then, by measuring the distance between annuli, the rate of growth can be calculated for each year group with this assumption that the distance between the annuli is in direct proportion to the growth in length of the fish for that period (Lagler, 1956). (See more in Text)

Library of Congress Subject Headings

Deer
Deer -- South Dakota

Description

Includes bibliographical references (pages 78-81)

Format

application/pdf

Number of Pages

91

Publisher

South Dakota State University

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