Interlake movements of wintering waterfowl on the Southern High Plains
A 2-year study was initiated on the Southern High Plains (SHP) of Texas and eastern New Mexico to determine distances moved by mallards (Anas platyrhynchos), wigeons (A. americana), green-winged teals (A. crecca), and northern pintails (A. acuta) from lakes in which epizootics of avian cholera have occurred. During the winters 1984-85 and 1985-86, 4,044 ducks were banded and marked with patagial tags. A total of 1,651 tagged ducks was sighted on surveys, of which 1,016 were identified by tag number. A total of 315 ducks was recaptured during the same winter as tagged. Of these, 80 individuals also were observed on surveys. One hundred forty-seven ducks were recovered, of which 28 also were observed on surveys prior to being recovered. Comparisons were made to determine if each species was reobserved in the same proportion as tagged, mallards were observed less often than expected, whereas wigeons and green-winged teals were observed more than expected. Pintails were observed in proportion to numbers tagged the first winter and observed less often than expected the second winter. Green-winged teals were observed close to their original capture site and had longer elapsed time intervals from tagging to observation. With several exceptions, mallards tended to be observed away from their original trap site and had relatively short elapsed time intervals. Pintails typically were observed the farthest from the original trap site and had the shortest elapsed time from tagging to observation. Wigeons appeared to be intermediate between green-winged teals and pintails. Within species, age and sex class was not generally related to distances observed or the elapsed time from tagging. Comparisons between numbers tagged and numbers subsequently reobserved found differences between months in 3 of 4 species during the winter 1984-85 and 1 of 4 species during the winter 1985-86, possibly reflecting differential migration and emigration patterns. In most cases, distances ducks were observed from the trap site within the study area were not related to elapsed time from tagging to observation. To determine if waterfowl return to the same wintering areas in succeeding years, 4,7 68 waterfowl were captured, banded and/or patagially tagged during the winters 1983-84 and 1984-85. Subsequent returns and recoveries within the study area during the winters 1984-85 and 1985-86 were used to determine minimum homing rates. Seventy-six ducks were known to return to lakes within 100 km^ of their original capture site. Ducks returning the succeeding winter, based on returns and recoveries, were highest in cinnamon teals (A. cyanoptera; 6.5%), mallards (1.7%) and wigeons (1.7%), followed by green-winged teals (1.3%) and pintails (< 0.1%).