Gary Krapu, PhD (Former Employee)

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...

Abstract has not been submitted

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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...

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...

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...