Some days we are ravens; other days, frogs

Ok . That's a new idiom and I'm not so sure what does it mean so be polite antimooners and could you help me to find our the meaning of that idiom.

That's one I've never heard! Where did you get that?

I've never heard that one either.

It was probably just made up.

No , no I have found it but I didn't make it up, I thought it could be mean something, but not so sure. http://palimpsest.typepad.com/frogsandravens/2004/11/index.html
So as I know we can learn so much from each other.

May be it doesn't mean nothing and I'm just trying to think what does it mean something which doesn't mean nothing. So how do we use our language? Do we know the meaning of so many meaningless words.

maybe it has some historical context and/or morals.
it might have meant something in a cultural story.

Yeah, I was trying to find out in Cambridge dictionary which Jim placed here one year ago, I was trying to google it ..and nothing, anyway, thank you.

It sounds like some kind of riddle.

I didn't say that YOU made it up; I meant whoever said it probably just made it up. The very few relevant google hits indicates that this is definitely not a well-known saying.

- Kef

It sounds like the summation of a longer parable or fable involving ravens and frogs, but it is probably specific to that particular context.

In other words, it isn't a popular fable or parable that most people know without having the story spelled out.