Is this a mom cat behavior?

Recently Mellie has been doing something that I've been wondering about. She has two toys that she does this with. One is an old sock with catnip in the stuffing, and the other is a little cloth-covered fish with catnip stuffing. She'll carry these things around in her mouth, and she'll make a sound that I can only describe as "keening." What comes across is a picture of a mother cat carrying around a dead kitten in her mouth, and mourning for it.

I was just wondering if this is a mother cat behavior? Or just one of those things that cats do that have no explanation?

I've always thought of it as announcing "this is my kill" to the other cats.

Could very well be. Hadn't thought of that. Thanks....

My Male cat carries his toys up the steps, he makes a mixed yowling/meow sound when he is doing this, hard to describe.

Is this the same thing you described with your female cat?

Yes, I think so. Must not be a mom cat behavior then, eh? Sorry for the delay in responding. Been very busy.