Let's think about the riddle step by step:
1. The bird is larger than a duck.
2. It isn’t meek, which means it can be a bit bossy or grumpy.
3. It often gets grumpy and pinches with its beak.
What bird could this be? A goose! Geese are bigger than ducks and are known to be a bit grumpy sometimes, and they can pinch with their beaks.
So the answer to the riddle is: Goose.