| Summary: | The whooping crane (Grus americana) is one of the most threatened crane species in the world and has been identified as an endangered species since 1967. The last wild-population of the whooping crane, the Aransas-Wood Buffalo Population (AWBP), breeds in Wood Buffalo National Park and surrounding areas in the Northwest Territories of Canada and migrates 2,500 km through the Central Flyway to their wintering grounds within the Aransas National Wildlife Refuge and surrounding areas on the Texas Coast. The Endangered Species Act (ESA) recovery plan for this species outlines objectives to down-list the species from endangered to threatened status, including an objective for a self-sustaining wild population size of at least 1,000 individuals, including 250 breeding pairs. However, the feasibility of meeting this objective requires an assessment of space-use by wintering whooping cranes and of the amount of available habitat within the winter range to support the recovery goal population size. Historic location data for 42 color-banded whooping crane individuals were used to analyze space-use strategies by three identified classes of cranes during the winter season; i.e., subadult (immature), associated (non-mating pair), and paired/family (mating pair). Space-use was analyzed by estimating winter whooping crane home range and core area extents from kernel density estimators. The resulting home range estimates supported previous descriptions based on observation data of the distribution of the three identified classes on the wintering grounds. The resulting core area estimates yielded a similar spatial distribution as winter territories identified by U.S. Fish and Wildlife Service annual winter monitoring, and identified a positive relationship between core area size and land cover diversity. To further evaluate the suitability of habitat for winter whooping cranes, Maxent software was used to create a winter whooping crane distribution model. The species distribution model was developed from over 5,000 whooping ...
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