Researchers at MIT and the Swiss Federal Institute of Technology Lausanne (EPFL) have built a small robotic bird capable of flying, diving into water, swimming beneath the surface and then launching itself back into the air, all using the same set of flapping wings. The team says this makes it the first bird-scale robot to complete a full air-to-water-to-air cycle without switching between separate propulsion systems, a feat that mirrors the natural abilities of roughly 100 real bird species but has long proved extremely difficult to replicate mechanically at small scale.

The robot weighs just 8.8 ounces (around 250g) and was reportedly built for about $300, making it a relatively cheap and lightweight platform compared with typical research drones. Engineers designed it to plunge beneath the water's surface, manoeuvre while submerged, and then use its wings to take off again from the water, replicating behaviour seen in diving birds that hunt underwater before returning to flight. The development is being framed as a significant engineering milestone with potential future applications in areas such as environmental monitoring or search-and-rescue, building on the wider trend of researchers looking to animal biomechanics for inspiration in robotics.