An expanding range of Allen's Hummingbirds (Selasphorus sasin sedentarius) in California, large-scale movements of migratory birds following a "green wave" of vegetation across the landscape in spring and Tree Swallows (Tachycineta bicolor) packing themselves into fewer sites than traditionally thought during the non-breeding season...these are just a few findings from recently published studies that have enhanced our understanding of avian communities in North America. As you may have guessed, these studies involved a tremendous amount of data, all of which were gathered by birders and submitted through the portal eBird, an avian reporting network hosted by the Cornell Lab of Ornithology. Without this massive data set representing information collected over broad geographic regions by thousands of dedicated individuals, the pace of our discovery would slow to a trickle.
