Robot bird swims underwater then flies away

Watching a diving bird vanish beneath the water can feel almost unreal. One moment it cruises through the sky. Seconds later, it swims after prey before returning to the air. Around 100 bird species can move between those two environments. Engineers have found that natural ability incredibly difficult to recreate at a small scale.

Now, researchers at MIT and the Swiss Federal Institute of Technology Lausanne, known as EPFL, have built a robotic bird that can complete the entire journey. The 8.8-ounce robot flies...