More than a century ago, Audubon pioneered the idea of citizen science with the first Christmas Bird Count. Today the longest-running wildlife census in the world continues to shape and inform our approach to conservation, providing vital information about bird populations and trends, data that alerts us to environmental threats not only to birds but to the larger ecosystems we all depend on. As partners with the Cornell Lab of Ornithology in ebird.org, Audubon helped transform citizen science into an everyday activity for tens of thousands of birders- community science. Their observations, reported online anytime and from anywhere throughout North America, provide an ongoing assessment of bird populations that is fast becoming an invaluable resource for conservation.