At precisely 10:48 p.m., the coyote passed the Reconyx PC800 camera strapped to a ponderosa, snapping three portraits of her lit by infrared flash. It was among eight cameras I’d set for Snapshot USA, a nationwide census of mammals. For two months, 150 participants canvassed forests, wetlands, deserts, prairies, urban parks, figuring out where mammals live, where they’re going, and what drives them. Survey coordinator Brigit Rooney, who annually sets cameras on her family’s property near Whitefish, Montana, once checked her memory card and saw a photo of herself -- followed, eight minutes later, by a mountain lion. The project began in 2019 and is now jointly run by the Smithsonian’s Conservation Biology Institute and the North Carolina Museum of Natural Sciences. Cofounder Roland Kays, a North Carolina State University biologist, says it will eventually create a long-term data set showing regional and national trends.