Breeding Birds of the Platte River Valley
Abstract
The Platte River Valley in central Nebraska is known throughout North America for its concentrations of sandhill cranes and waterfowl during spring migration. Fully three-quarters of the world's population of lesser sandhill cranes (Grus canadensis), nearly all of the Central Flyway population of greater white-fronted goose (Anser albifrons), and over one million Canada geese (Branta canadensis) spend most of the period from mid-February to early April along the Platte River. The yearly spectacle makes the Platte River a birdwatcher's paradise.
The habitats native to the area, along with the status and distribution of breeding species occupying the region, have changed considerably in the last hundred years. Alteration of the central Nebraska landscape began with the arrival of the first European settlers in the mid 19th century. Agricultural irrigation projects were initiated that ultimately altered the dynamics of the Platte River system. Once described as "a mile wide and a foot deep," annual flows in the Platte River had been reduced to about 32% of their pristine levels by 1978. Several development projects proposed within the Platte River system in Colorado, Nebraska, and Wyoming currently threaten to degrade further the existing natural habitats. Expanded withdrawal of Platte River water will not only impact riparian habitats, but will contribute to additional degradation of native upland habitats. Our work provides baseline data on the current status of the habitats and their breeding birds within the Platte River Valley that can be used to evaluate water development and human impacts in the future.
Most ornithological interest in the Platte River system has centered on birds using the area during spring migration. The breeding avifauna of the area is large and diverse, including about three-fourths of all bird species known to nest in Nebraska. Included in this total are two bird species recently listed as endangered or threatened by the U.S. Fish and Wildlife Service, and several other species that are fast approaching endangered status. During 1978-1980, we conducted extensive surveys of the breeding bird population occupying the Platte River Valley from Central City west to Colorado on the South Platte River, and to the Garden - Morrill County line on the North Platte River. During 1981-1988, we continued to study the breeding birds of the eastern third of our area. The main objective of our field research was to determine the numbers and kinds of bird species nesting in the area, their populations, habitat preferences, and the geographical distribution of each species across the area.
We include information about species status (including nests, fledglings, and nesting attempts), distribution, habitat use during the breeding season, the effect of habitat alteration on species distribution and abundance.
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