Quiet Ornithopter Drones

Clear surveillance will take a different angle soon.   Their use of 'biomimicry' uses birds to some degree.   Differences are interesting, they can point to changes that would be useful. Biomimicry for emergent tech is often covered here.

High Performance Ornithopter Drone Is Quiet, Efficient, and Safe

Flapping wings instead of propellers help this bird-inspired drone hold its own against quadrotors By Evan Ackerman in IEEE Spectrum

The vast majority of drones are rotary-wing systems (like quadrotors), and for good reason: They’re cheap, they’re easy, they scale up and down well, and we’re getting quite good at controlling them, even in very challenging environments. For most applications, though, drones lose out to birds and their flapping wings in almost every way—flapping wings are very efficient, enable astonishing agility, and are much safer, able to make compliant contact with surfaces rather than shredding them like a rotor system does. But flapping wing have their challenges too: Making flapping-wing robots is so much more difficult than just duct taping spinning motors to a frame that, with a few exceptions, we haven’t seen nearly as much improvement as we have in more conventional drones. .... "