I'll put it simple: let's say you have a drone that can fly for 30 minutes, but you want it to fly for 45 minutes. What should you do? You could land him on a tree branch to get some rest, save energy, and continue filming. To do this, Stanford University engineers studied the hawk to make a special landing gear.
Mark Cutkosky and David Lentink, these are the names of the researchers, invented a system of legs and claws called SNAG (Stereotyped Nature-inspired Aerial Grasper). They had initially tried to mimic the properties of a parrot in being able to stand on a perch: nothing could be more wrong. For the size of a four-engine drone we needed to be inspired by a bigger bird. Nothing better than the hawk, a perfect combination of strength and agility.


Strike like a hawk, fly like a drone (it could have been better).
Instead of bones, a 3D printed structure. Instead of muscles and tendons, motors and cables. What does the hawk drone lack to be efficient (and also awe-inspiring)? Nothing. Nada. Nothing.
In summary, this robot has paws with two motors: one moves the paw back and forth, the other makes sure that when the "hawk" lands, its grip is stronger so as not to fall. How? Using a mechanism similar to that of bird tendons, which move around the ankle. The result? The drone it has a strong and very fast grip (only 20 milliseconds). When its hawk claws wrap around a branch, an accelerometer signals that it has landed, and activates a balancing algorithm to keep its grip stable.
Take a look at how it works:
Robot birds (this is better, admit it)
And we come to practical applications, before some neo-Luddites rise up saying "spend this money to do serious things!". Roderick and the Stanford researchers hope that SNAG will help people who study the environment first. He and his team tested the hawk drone for microclimate analysis, for example.
If we can develop a bird robot like this, we will be able to collect data on the environment in a way never seen before, in unprecedented detail. Fly, friend! (But keep your claws three feet away from me).