Document Type

Thesis - Open Access

Award Date

1968

Degree Name

Master of Science (MS)

Department

Wildlife Management

Abstract

Ecology and behavior of breeding blue-winged teal (Anas discors) were studied in northeastern Day County, South Dakota in 1965 and 1966. Breeding pair use of the wetland habitat and importance of Type 1 ponds in the wetland complex were evaluated. Pair densities of 30.7 and 33.0 per square mile in 1965 and 1966, respectively, were above the 16-year average from 1950-66 and near maximum. Blue-winged teal comprised 46.7 percent of the waterfowl breeding population in 1965 and 51.7 percent in 1966. Number of water areas per square mile through mid-spring 1965 was comparable to the average for the 16-year period 1950-66, whereas during late spring 1965 and throughout the 1966 spring breeding seasons the number of water areas increased to near optimum conditions. Annual breeding-pair densities from 1950-66 appeared to be largely influenced by water conditions, and pair-density fluctuations resulted from changes in number of wet ponds from late April through mid-May. Variations in water conditions after this period did not appear to have as great an effect on teal numbers. Home ranges of 14 blue-winged teal pairs averaged 160 acres and ranged from 74 to 215 acres. Activity centers, the functional part of the home range, averaged 24 acres for 12 pairs, and ranged from 10 to 39 acres. Primary waiting areas of drakes were usually located on water closest to the nest. Use of wetland habitat by pairs changed throughout the spring breeding seasons. During the post-arrival period teal congregated on larger wetlands. With onset of egg-laying, pairs dispersed into ponds throughout the wetland complex to establish breeding home ranges. Other factors that influenced changes in habitat use included: 1) pond type and size, 2) availability of wet ponds, 3) breeding cycle phenology, and 4) land use, Number of blue-winged teal pairs per unit area of water was highest in 1965 and 1966 on Type 1B ponds, followed in decreasing order by Types 3, 1A, and 4 and 5. Greater use of Type 1B ponds was probably related to larger ratio of edge or shoreline to unit area of water. Interspersion of many small wetlands throughout the breeding habitat provided for maximum pair dispersal during egg-laying and early incubation stages of the reproductive cycle.

Library of Congress Subject Headings

Blue-winged teal
Wetland ecology -- South Dakota
Waterfowl -- Breeding -- South Dakota

Description

Includes bibliographical references (pages 95-98)

Format

application/pdf

Number of Pages

109

Publisher

South Dakota State University

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