For birders, researchers, and conservationists alike, the Cornell Lab of Ornithology’s eBird platform has been a game changer. Not only can its crowdsourced data help you locate rare birds and hotspots, but its collection of more than 1.5 billion records contributed over the past 20 years has also proven a vital resource for science and conservation. For example, the Cornell Lab’s Migration Dashboard, part of the BirdCast tool, uses historic eBird observations for a given date and location to let users see what birds might be flying overhead in spring and fall. eBird data submitted by community scientists have also revealed migration pathways and underscored how vulnerable migratory birds are to light pollution. For birders, eBird offers two main functions. You can explore a vast trove of data shared by other birders, helping you learn about species within a particular area and find new places to bird. And you can submit your observations to track your life list and...