I was breeding Rookidee for a shiny, and all of them have Drill Peck even though They’re level one. I know the dad Corviknight has the move. Could someone explain why?
My bet is that both Parents know the move Drill Peck. As Rookidee can learn Drill Peck at Level 28, it is possible for Rookidee to know Drill Peck at Level 1. How this works is that if both Parents know a move the child can learn via level up, it will know it.
* Exception being it learns 4 or more moves at level 1.
I believe it has something to do with breeding. So, since you may be breeding with another corviknight that knows drill peck, it got it. I have heard that only female corvinight can pass down egg moves, but this may be wrong so take this sentence with a grain of salt.
Drill Peck is an Egg Move for Rookidee. That means that a parent who knows the move will pass it to the offspring. This is also the only way to teach a Rookidee the move Roost, which is critical for any of the Brave Bird strategies.