The use of US Army Corps of Engineers reservoirs as stopover sites for the Aransas–Wood Buffalo population of whooping crane

Abstract

This technical report summarizes the use of US Army Corps of Engineers (USACE) reservoirs as spring and fall migration stopover sites for the endangered Aransas–Wood Buffalo population of whooping cranes (WHCR), which proved much greater than previously known. We assessed stopover use within the migration flyway with satellite transmitter data on 68 WHCR during 2009–2018 from a study by the US Geological Survey (USGS) and collaborators, resulting in over 165,000 location records, supplemented by incidental observations from the US Fish and Wildlife Ser-vice (USFWS) and the USGS Biodiversity Information Serving Our Nation (BISON) databases. Significant stopover use was observed during both spring and fall migration, and one reservoir served as a wintering location in multiple years. Future efforts should include (a) continued monitoring for WHCR at USACE reservoirs within the flyway; (b) reservoir-specific management plans at all projects with significant WHCR stopover; (c) a USACE-specific and range-wide Endangered Species Act Section 7(a)(1) conservation plan that specifies proactive conservation actions; (d) habitat management plans that include potential pool-level modifications during spring and fall to optimize stopover habitat conditions; and (e) continued evaluation of habitat conditions at USACE reservoirs.