Dumb driver or bird???

As I cruising down the road at 70km/h, is a 3 lane roads, so is 6 lane all together on both side. is at about 7:45pm.... cruising slowly, is quite dark, so all cars with headlight ON. Paying attention on the road, suddenly saw something small moving from far left. As I get closer, and is too late, one of the bird is gliding crossing the roads. what the.... and I think it did not manage to react fast enough, it hit the top of my car windscreen as it trying to pull up.... Don have a chance to see if it been hit and swing away or the flying action just suddenly went tripped over and make a few rolling before resume the flying or land on the grass....
Whose fault??? Bird or driver?