Field-Feeding Ecology of Waterfowl Wintering on the Southern High Plains of Texas

Abstract

The ecology of field-feeding dabbling ducks wintering on the Southern High Plains was investigated on a 50-km2 study area in Castro County, Texas, from Sept.-March 1980-1982. Most ducks participated in 2 feeding flights/day to harvested cornfields, which occupied about 45% of the study area. The average morning flight was initiated 52 .+-. 1.5 min before sunrise and terminated 23 .+-. 1.4 min later. Evening flights began 25 .+-. 2.0 min after sunset and ended 37 .+-. 4.2 min later. The duration of evening flights increased as the season progressed, and birds fed longer and participated more in the evening flight compared to the morning flight of the same day. Colder temperatures and snowfall were associated with longer evening, but not morning, flights. Feeding flocks selected fields based on an abundance-availability hierarchy, apparently attempting to minimize foraging time. Burned fields were preferred when available, followed by disked fields, especially those containing > 60 kg waste corn/ha.