Gary Krapu, PhD

We measured the effect of diet quality on variation in the seasonal pattern of Mallard (Anas platyrhynchos) reproduction. Twenty wild-strain hens, consisting of 10 sibling pairs, were maintained in captivity. One sib of each pair was fed an enriched diet, and the other was fed wheat. The wheat diet resulted in reduced clutch size, egg size, laying rate, number of nesting attempts, and total eggs l

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The number of cliff swallow (Petrochelidon pyrrhonata) nests at a farmstead in southeastern North Dakota increased at an average annual rate of 87% with house sparrow (Passer domesticus) removal during 1957-60 and 1970-72. Harassment of nesting cliff swallows by house sparrows, adult swallow mortality from cold weather in late May, and collapse of nests were the principal observed factors limiting

We studied the food habits of midcontinent sandhill cranes (Grus canadensis) during spring 1978 and 1979 at their primary staging area along the Platte River and compared population food and foraging habitat requirements with availability. Crane diets varied among the 3 principal foraging habitats, but not between sexes, ages, or years. Cranes feeding in cornfields ate >99% corn (total dry wt); th

Approximately 200 bald eagles wintered along a 370-km section of the Platte and North Platte rivers in Nebraska during the winters of 1978-79 and 1979-80. A preponderance of the wintering eagles were adults, with the adult:subadult ratio highest during the harsh winter of 1978-79. Nocturnal roosts were located primarily in tree plantings near the river, with mean tree age at the roosts ranging fro

A Lipid Index, the ratio of fat to fat-free dry weight, is proposed as a measure of fat stores in birds. The estimation of the index from field measurements of live birds is illustrated with data on the sandhill crane (Grus canadensis) and greater white-fronted goose (Anser albifrons). Of the various methods of assessing fat stores, lipid extraction is the most accurate but also the most involved.

Body weight, fat, and protein levels of arctic-nesting Sandhill Cranes (Grus canadensis) were measured at several locations during spring migration and on the breeding grounds. Body weights of adult males and females increased by about 34% (1,129 g) and 30% (953 g) from early March at the Platte River to late April at Last Mountain Lake, Saskatchewan; average fat content increased from about 250 t

The principal spring staging areas of the midcontinent population of sandhill cranes (Grus canadensis) are along the Platte and North Platte rivers in south-central Nebraska. Most of these lands are privately owned and managed for corn and cattle production. Diurnal habitat use by radio-tagged cranes was primarily in cropland (55%), native grassland (28%), and tame hayland (15%). Ninety-nine perce

Of about 140 extant species of waterfowl in the world, 54 occur in the western Pale- arctic. In this, his most recent book, Ogilvie introduces the reader to the waterfowl of Europe including occasional visitors and introduced species. Although written primarily for laymen, ornithologists will find the book informative but should not expect a major treatise on European waterfowl. The text is drawn

Abstract has not been submitted

Abstract has not been submitted