Evaluations of Duck Habitat and Estimation of Duck Population Sizes with a Remote-Sensing-Based System.
Biological science rept. no. 2,
NATIONAL BIOLOGICAL SERVICE FORT COLLINS CO MIDCONTINENT ECOLOGICAL SCIENCE C ENTER
Pagination or Media Count:
During 1987-90, we used high-altitude photography, aerial videography, counts, and models to estimate sizes of breeding populations of dabbling ducks Anatinae and duck production and to identify duck habitat on U.S. Fish and Wildlife Service land and easements and on private land pothole region of the United States. in the prairie km2. Wetland area ha per km2 The study area contained about 3.1 million wetland basins 28,490 was highest on service-owned land wetland-basin density was greatest on service easements. Temporary and seasonal wetlands were underrepresented and lakes were overrepresented on service-owned land. Seventy-eight percent of all basins were less than 0.41 ha. Cropland dominated private land. Pond density decreased from 4.4km2 in 1987 to 3.4km2 in 1990 and pond area, from 7.2 hakm2 to 2.7 hakm2. The density of the blue-winged teal was greatest 3.4 pairskm and was followed in magnitude by those of the mallard 2.1 pairskm2, the gadwall 1.8 pairskm2, the northern pintail 0.8 pairskm , and the redhead 0.8 pairskm2. Duck density was consistently highest on service-owned land. The decline of breeding-population sizes in 1987-90 closely corresponded to losses of pond numbers and pond area. The density of breeding pairs per pond was inversely related to pond density, suggesting that breeding ducks tended to concentrate on the remaining ponds as drought intensified. The production of recruits followed the same pattern as breeding-population sizes. We estimated that 2.5 of the ducklings hatched on service-owned land, which was 1.3 of the study area 19.6 hatched on service easements, which were 14.2 of the study area and 77.9 hatched on private land, which was 84.6 of the study area.
- Acoustic Detection and Detectors