Climatic shifts drove major contractions in avian latitudinal distributions throughout the Cenozoic

The fossil record reveals evidence of dramatic distributional shifts through time for many groups of organisms. One striking example is the early fossil record of modern birds, which shows that many bird groups currently restricted to the tropics were formerly found at high latitudes in North America and Europe. Tracking potentially suitable habitat for these clades over the last 56 million years reveals that cooling trends throughout this period may have largely dictated the geographic distributions of these "tropical" groups, complicating our understanding of where on Earth many of these lineages originated.