Numerical response of wintering waterfowl to macrohabitat in the southern High Plains of Texas

Populations of pintails (Anas acuta), American wigeon (A. americana) , mallards (A. platyrhynchos) , and green-winged teal (A. crecca) were studied on 10 23.04-km^2 plots in the Southern High Plains of Texas during September-March 1980-1981 and 1981-1982. Peak total populations occurred in November and February, largely because of massive influxes of pintails during these months. Mallard and wigeon populations were relatively stable after peak numbers arrived on the wintering areas and before spring migration. Sex ratios observed in this study were similar to those reported in other portions of the Southern High Plains. The estimated percentage of males was similar (P>0.05) each month during October-March for mallards and wigeon but was lower (P< 0.05) in December 1981 (58%) than in January 1982 (70%) for pintails and in October-November 1980 (47-49%) than in December-March 1980-1981 (72-80%) for green-winged teal. Availability of waste corn in disced fields was relatively constant throughout the winter because as fields were plowed the stubble in other fields was disced. Less than 3% of the corn stubble was burned. Multiple regression models that predicted monthly waterfowl use of plots based on hectares of macrohabitat were acceptable for total ducks, wigeon, and pintails but were not acceptable for mallards and green-winged teal. Hectares of water, corn, and wheat positively affected waterfowl use whereas hectares of sorghum, cotton, and other land uses negatively affected waterfowl use. The models can be used to determine the most effective and cost-efficient management measures to increase or decrease waterfowl populations on wintering areas in the Southern High Plains of Texas.