ABUNDANCE AND DISTRIBUTION OF LESSER SNOW AND ROSS’S GEESE IN THE RAINWATER BASIN AND CENTRAL PLATTE RIVER VALLEY OF NEBRASKA

摘要

The number of lesser snow geese (Chen caerulescens) and Ross’s geese (C. rossii), hereinafter called “light geese,” staging during spring in the Rainwater Basin and Central Platte River Valley of south-central Nebraska has dramatically increased since the late 1980s. However, there has been no documentation of the abundance or distribution of light geese across the Rainwater Basin and Central Platte River Valley and the relationship of distribution to conservation-order activities. We used aerial transect surveys and distance sampling methodology to estimate abundance and distribution of light geese in the Rainwater Basin and Central Platte River Valley in the spring of 2001, 2002, and 2003. In 2001 at peak migration, we estimated approximately 7.3 million light geese in the Rainwater Basin and Central Platte River Valley. In 2002 and 2003 there were approximately 1.2 million and 1.6 million light geese at peak migration, respectively. Distribution did not appear to change in relation to light goose conservation-order activities. However, there was an increased use of the Central Platte River Valley during 2002 and 2003 due to dry conditions. The Rainwater Basin and Central Platte River Valley have become a major spring staging area for light geese. Abundance and distribution appear to be related to water conditions and migration chronology.