Gary Krapu, PhD (Former Employee)

Sex and age ratios, habitat selection, spatial characteristics, and time budgets of Mallards (Anas platyrhynchos) wintering on the Platte River in south central Nebraska were studied from mid-December to early April 1978-1980. The proportion of females and subadults in the population increased substantially from a cold to a mild winter. Radio-tagged Mallards shifted from riverine to...

Food use by mallards (Anas platyrhynchos) wintering on the Platte River in south central Nebraska was determined from mid-December to early March 1978-80. Mallards foraged in river channels, irrigation drainage canals, and agricultural areas. Plant matter formed 97% of the diet (dry weight) and diets did not vary between sexes (P > 0.05). Waste corn was the principal food consumed and...

Mallard (Anas platyrhynchos) breeding densities in the prairie pothole habitat of eastern North Dakota during 1961-1980 varied from 2.28 birds/km2 in 1977 to 9.47 birds/km2 in 1963 and were correlated with pond abundance (r = 0.543, P 0.05). The number of basins used by pairs declined with drought, as did home-range size. Nesting activity also varied with the number of ponds holding...

This book is a compilation of papers from the extensive and varied published literature on the ecology and management of waterfowl. The 125 technical papers reprinted in this book are arranged in eight major sections and are from 21 journals, government reports, several books, and proceedings of symposia and annual conferences. The most frequent sources of papers are The Journal of...

This is the 3rd edition of the classic work "The Ducks, Geese and Swans of North America," which was first published in December 1942. The original edition was authored by Francis C. Kortright with color plates by T. M. Shortt. An authoritative reference on North American waterfowl for many years, the book had become outdated as a result of major advances in the field of waterfowl...

Mallard (Anas platyrhynchos) populations breeding in temperate North America obtain a significant part of the energy and lipid requirements of reproduction at sites occupied prior to arrival on the breeding grounds. Protein for egg formation, however, is obtained principally from the diet during the nesting period. Both sexes arrive heavy and fat in North Dakota but experience...

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Detailed information on the use by mallards (Anas platyrhynchos) of prairie pothole habitat during the nesting season is necessary to interpret habitat needs of the species during the breeding period. Many data have been collected and published relating pair counts to habitat use and water conditions (e.g., Evans and Black 1956; Smith 1971; Stoudt 1971; Stewart and Kantrud 1973, 1974)...

A technique for distinguishing adult from yearling wild mallards (Anas platyrhynchos), from late winter through the nesting season, was developed by applying discriminant analysis procedures to selected wing feather characters of 126 yearlings and 76 adults (2-year-olds) hand-reared from wild eggs during 1974, 1975, and 1977. Average values for feather characters generally increased as...

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