This book summarizes the evidence from 47 years (1967-2014) of Audubon Christmas Bird Counts and finds that bird populations and winter ranges have changed for many species in the Great Plains states (the Dakotas, Nebraska, Kansas, Oklahoma, and the Texas panhandle). The book offers quantitative descriptions of the winter abundance for 147 of the most commonly encountered regional species, illustrating their changes in geographic distributions and relative abundance between 1967 and 2014. As winters have become progressively warmer, the winter distributions of many birds have moved northward, by as much as two states for some species. Birds are responding to milder temperatures and longer periods of ice-free water and snow-free foraging sites in the Great Plains, and the shifts in their distribution provide critical indicators of the acceleration of global warming.