I've heard of both.
Some people poo poo the idea of the wx radar and lights, but as you inject a flock of canadian geese at 200' after takeoff you'd probably try yelling out the window at them!
I haven't heard of any official theories but with modern radars the output is a lot lower than that of the older technology radars, so I doubt whether it really does anything much.
Just found this which pretty much answer the question.
Bird laughs in the face of wx radar....