What has it taken down in real world? Russians claim their tech can shoot down anything but Israel has proven otherwise. Pantsir has problems telling difference between birds and drones, etc.
The flip side of it, that means the Pantsyr can detect, track and lock something with the RCS of a small bird with those mobile radars.
Real world seems to be telling different story than marketing people and fanboys.
Radar isn't like sight, there is no way for it to image the bird from a drone like optics. The radar needs to find a way to differentiate the backscatter of a bird versus a drone. Kind of like this. You have to take account of the wing beat, so the object reflects radar in a way that is not constant but fluctuates with the wing beat. With a drone, lets say, with propeller, that has a different backscatter, depending on how fast the propeller rotates, it also creates a weird reflecting signal that times with the rotation of the propeller. Same with helicopter type propellers.
With jet type drones its very easy. Because its moving much faster than a bird, so much faster, its easy for the fast mover to show up using Moving Target Indicator or Pulse Doppler. Bingo, you know that ain't a bird if its moving at 300 kph. Then you need to know if the drone or jet is friend or foe, so your IFF goes to work to interrogate the target. If the target fails to respond or sends the wrong code, it becomes literally a target.