In a lab filled with sensors, circuits, and cables, Alejandro Rico-Guevara has devised what may be the world’s strangest hummingbird feeder. Responding to timed lights and beeps, the hungry guests stick their beaks into a flower-shaped contraption and hover for a beat so a machine has time to gauge their oxygen intake. After, a tiny computer-controlled gate opens to a sugary reward. At least that’s the idea. Getting the setup right has taken months of tinkering, says the University of California, Berkeley evolutionary biologist. “The birds are hard-wired to be fast,” Rico-Guevara explains. “We are trying to reverse all these years of evolution with training.” Growing up in Colombia, Rico-Guevara never paid much attention to how gadgets worked; he was always more fascinated by the natural world. But these days, in his quest to better learn how hummingbirds consume and use energy, he’s as likely to play around with microcontrollers as traipse through a tropical...