PATTERNS OF HABITAT USE BY WHOOPING CRANES DURING MIGRATION: SUMMARY FROM 1977–1999 SITE EVALUATION DATA

• Main Authors: Austin, Jane E., RICHERT, AMY L.
• Format: Text
• Language: unknown
• Published: DigitalCommons@University of Nebraska - Lincoln 2005
• Subjects: Grus americana; habitat use; migration; whooping crane; Animal Sciences; Behavior and Ethology; Biodiversity; Ornithology; Population Biology; Terrestrial and Aquatic Ecology; Wood Buffalo
• Online Access: https://digitalcommons.unl.edu/nacwgproc/8; https://digitalcommons.unl.edu/context/nacwgproc/article/1001/viewcontent/Austin____Pattersn_of_Habitat_use.pdf

We used site evaluation data collected during 1977–1999 to examine patterns of habitat use by whooping cranes (Grus americana) during migration through the United States portion of the Wood Buffalo–Aransas flyway. We examined characteristics of 3 types of stopover habitats: 1) roost sites (n = 141 records), 2) feeding sites (n = 306), and 3) dual-use sites (i.e., where observer recorded cranes as using a site for both roosting and feeding (n = 248). Results in spring were influenced by the large number of records from Nebraska (> 67% of spring records) and in fall by frequent observations on Salt Plains and Quivera National Wildlife Refuges and Cheyenne Bottoms State Wildlife Area. Palustrine wetlands were the most commonly recorded wetland system (68.8%) used by whooping cranes; riverine wetlands accounted for 21.6% and lacustrine wetlands 9.6% of site evaluation records. Riverine sites were common only in Nebraska, where they accounted for 59.0% of roost sites. All social groupings of whooping cranes used palustrine wetlands for both roosting and feeding, whereas most of the whooping cranes found on riverine roosts were single cranes or nonfamily groups. Most wetlands used by cranes were seasonally or semipermanently flooded. Observers found whooping cranes on a wide range of wetland sizes. River widths ranged from 36 to 457 m and averaged 227 ± 88 (SD) m. Maximum depths of wetlands on which observers saw cranes ranged from 3 to 305 cm and averaged 51 ± 41 cm. Specific sites within wetlands where observers recorded cranes feeding or roosting averaged 18 ± 11 cm (range 3-61 cm). Observers described most wetlands as having soft substrates, low shoreline slope (< 5%), and clear or turbid water. Riverine roost sites and dual-use sites were consistent in their lack of vegetation, but palustrine sites varied in types of emergent vegetation and their distribution. Feeding sites were largely upland crops, with lower occurrence of seasonal or permanent wetlands, or upland perennial cover. At dual-use sites, ...