The Aransas-Wood Buffalo population of whooping cranes (Grus americana) declined to near extinction by the 1940s. Starting in winter 1950-1951, annual aerial surveys were conducted to observe and record the number of whooping cranes wintering on Aransas National Wildlife Refuge and surrounding areas.
This effort resulted in 38,332 observations of whooping crane groups being marked on paper maps between winter 1950-1951 and winter 2010-2011. U.S. Fish and Wildlife Service staff recently digitized those locations and archived them in single file, “WHCR_Aerial_Observations_1950_2011.txt”, which is available for download at http://dx.doi.org/10.7944/W3RP4B. These data are freely available to the public. However, we caution that these data have quality issues and limitations (see documentation for additional details).
Taylor, L.N., L.P. Ketzler, D. Rousseau, B.N. Strobel, K.L. Metzger, and M.J. Butler. 2015. Observations of whooping cranes during winter aerial surveys: 1950-2011. Aransas National Wildlife Refuge, U.S. Fish and Wildlife Service, Austwell, Texas, USA. http://dx.doi.org/10.7944/W3RP4B.