The unsteady comeback of the California condor

Californian condors are a species of vulture; they feed on dead animals. Adults can have a wingspan of up to three metres, making them the largest land bird in North America. As America’s population grew in the 19th and 20th centuries, the birds’ numbers plummeted. They were placed on the federal endangered-species list in 1967, but they continued to die off. Their near-demise, and recent comeback, provide a study in unintended consequences.