Watch the Supercarlinbrothers video in it

Because that would be boring if it was a raven, and Ravenclaws are nothing if not interesting

Because Rowena is above bad puns.

Because Ravenclaw is a surname. But if you want to follow that logic then Gryffindor's symbol would be a griffin. And Hufflepuff's would be someone with asthma. But the founders chose the animals that best represented their core values. Ravenclaw is represented by the eagle who "soars higher than others" referencing high intelligence and thinking outside of the box. And each house represents one of the four elements, this one air. Finally the colors blue and bronze represent the sky and the eagle's feathers.

Because it represents the founders personality not animals lol

Just like Gryffindor's symbol is a lion not a gryffin