Why is the mom always in a costume when the kid is around?

I'm pretty sure it's cause the mom is a guy

maybe the mom doesn't want to show his kid that he is actually a male. Maybe because he's afraid that the kid will reject him.

And the kid just accept it like that? That his mom in a bird costume? (￣∇￣")

True, but what would the others say, like kids at school. with the suit they can say she has a sun allergy or some kind of excuse. so far all we've seen is the family, not the environment, so they may be trying to protect him.

true but you know this is just a manga. i don't what kind of fantazies the author has ....but yeah anything is here possbile(￣∇￣")

*know

^^ Yep ^^ but, it makes it different and its fun to guess, so I guess its a bonus that hopefully will be explained later.