Hitting a single bird can take down a plane. Here's some cockpit footage:

https://www.youtube.com/watch?v=rNqU8jfAJMQ

Here's that didn't take down the plane, but made a big hole in the canopy spewing blood and guts all over the person in the back seat with the body hitting them in the shoulder.

https://www.youtube.com/watch?v=XAn6yBJjC8g