The problem is that you can't look at a God as an equivalent of a person with a distinct and very limited identity. The gods we more fluid in how they were represented and worshipped and during the time in which they were worshipped. When simply enumerating that Hera's sacred birds are a Cuckoo, Peacock, etc., you lose that people living in one community may have had a lot of Peacocks but had never seen a Cuckoo before, so they naturally revered the Peacock instead.
> Priest: And Hera's sacred bird is the Cuckoo
>
> Worshiper: Ohh. What's a "Cuckoo"?
>
> Priest: Uhm, [ _looks around frantically_ ] ... that bird over there!
>
> Worshiper: ...Looks kind of like a Peacock to me.
>
> Priest: Well, it would. That is why I am a priest. Now kneel before the goddess and pray or I will give you such a pinch!!