Date of this Version
PROCEEDINGS OF THE NORTH AMERICAN CRANE WORKSHOP 13:1-12
We used compositional analysis to describe habitat use for a dense population of breeding sandhill cranes (Grus canadensis tabida) in central Wisconsin at 2 spatial scales: selection of home range within a study area and selection of habitats within the home range. Habitat use and home range size were estimated from radio-telemetry data from 12 breeding sandhill crane pairs. Research in Wisconsin that was performed on the landscape level suggests that breeding cranes depend on wetlands and do not select upland habitats. Evaluating habitat selection at different spatial levels, such as during different stages of the breeding season, can better illustrate the hierarchical nature of selection by breeding sandhill cranes. In establishing home ranges, breeding cranes selected wetland habitat over all other land-use categories. Within home ranges, breeding cranes still selected wetland habitat above all other habitat types; however, row crops and tall grass were also important. During daylight hours, habitats that were used consisted primarily of wetland (38.7% ± 4.5 [mean ± 1 SE]), row crop (24.3% ± 5.7), and short crop (14.0% ± 4.6). Home range size as well as the selection of habitat type was not constant during the breeding season. On average, home range size during the post-fledging stage was 3 times greater than pre-fledging stage. Wetlands were used daily (97.4% of all days) throughout the breeding season but for a greater percentage of each day when chicks were small than when large. Wetland accounted for 50.1% of all locations during the pre-fledging stage and for 30.6% of all locations during the post-fledging stage. The knowledge that breeding cranes require emergent wetlands at all spatial and temporal scales, but that the presence of both upland and wetland habitat within a home range is important, provides a greater refinement to the understanding of habitat needs of breeding sandhill cranes in Wisconsin.