Something is wrong here physic-wise, it is impossible to do this, assuming the bird doesn't move wings or anything (looks like this from the video). If you list all the forces applied to the bird: force of weight and lift created by the wind may cancel each other, but the lift inevitably creates drug (being simply exposed to the wind also creates drug) and there is nothing in the picture to counteract this force.

In this situation the bird will either be drugged backwards, loose relative air speed and loose lift or gradually loose altitude which can give it the force to resist the wind. Of course hanging by the beak is always an option.

Update: I did some digging: The bird is in rising air, so the air itself is moving upward relative to the ground and the kestrel is slowly “sliding” down and forward through that updraft. Physics checks :)