Are Those Birds Best Friends?

At first we thought is was a mama robin with a baby robin in the front yard. Each move the mother made, the baby made in turn. But upon closer examination it appears that the baby robin is actually a full grown sparrow. Huh. Funny.

But then there they were the next day, doing the same thing. Big robin hops a few feet to the right, little sparrow hops a few feet to he right.

And then today there they are again only this time they are on a different street. As I stroll past, the big robin looks up and then the little sparrow looks up.

Are they friends?