The astonishment expressed by so experienced an observer as John James Audubon as he described a flock of passenger pigeons darkening the Kentucky sky for three days finds it tragic counterbalance in the seemingly inexplicable extinction of Ectopistes migratorius just over a century later. How did this happen so quickly to what was once the most abundant bird in North America? And what could we have done differently?
Here, the author marks the centenary of the last bird’s demise in a Cincinnati zoo with a comprehensive reconstruction of its rapid decline and loss as well as a retrospective IUCN Red List assessment. GBIF-mediated specimen records contribute to the breeding habitat portion of a highly detailed model, which also accounts for the passenger pigeon’s erratic migrations, habitat loss and nesting collapses. The results not only resolve the central mystery, attributing primary responsibility to decades of commercial overharvesting, but also suggest that regular Red Listing would likely have unmasked the rising extinction risk—thereby signaling the present-day importance of species monitoring strategies in an era of rapid environmental change.