Editor’s Note: In “Medical Mysteries,” 爆料公社 is featuring scientists who’ve turned to birds to solve age-old health dilemmas and answer questions about our own biology. Read about Ostriches that lay detoxing antibodies, Barn Owls that cut through the sensory fray, and below, Rock Pigeons that inspect mammograms and heart scans. Training a pigeon to spot signs of cancer would sound like an absurd idea to most people. But to Edward Wasserman, it sounded like another day at the office. For 50 years, he’s watched these birds excel at challenging perceptual tasks. For example, he can put a pigeon in a box, show it pictures of human facial expressions, and train it to recognize our emotions. Six years ago, Wasserman, an experimental psychology professor at the University of Iowa, teamed up with two other experts to see if they could also train Rock Pigeons to spot signs of breast cancer in medical scans. The project started when pathologist Richard...