When Anders Møller stumbled across a century-old paper describing sperm-milking techniques for artificially breeding budgies, he knew he was on to something good. Although sperm harvesting—which involves gently pressing on the muscles around a male bird’s cloaca, causing a contraction that triggers (nonconsensual) ejaculation—is practically an art among turkey and chicken farmers, it’s not a skill taught at ornithology school.As with any other skill, practice makes perfect, so Møller—an evolutionary biologist and research director of the French National Center for Scientific Research—began experimenting in the field with some very unhappy males. “In the early years, half of his attempts led to something other than semen being produced,” says Timothy Mousseau, a biologist at the University of South Carolina and Møller’s longtime collaborator. “The samples were just filled with shit.”Thousands of, er, massages later, Møller is now a pro. He recently put that...