Helen Hays first saw fishermen wearing her bird-tracking bands as jewelry in 2002. The American ornithologist and conservationist flew down to Brazil’s northeastern corner after getting a call from Pedro Cerqueira Lima, a fellow ornithologist. He was worried about their research subjects. She and Lima, who is also a veterinarian in Brazil, had been partnering for almost 10 years, hoping to learn more about small, endangered seabirds called roseate terns (Sterna dougallii).