Perhaps they do it because they're lonely, or because they're bragging about their "kill," or some other reason. To me, it sounds as though she's telling her pooky something Very Important.
I was thinking recently that it's all pretty amusing, and then I had a thought: don't I sing to my pooky? To all my pookies? Also known as my cats. I call them and hold them and tell them silly sweet nothings, often for no reason at all. Someone who didn't know my language might think it pretty amusing when I scoop up Greykin and cuddle him, asking him if he's my "best boy." What about when Dorian and I have a mewing and squeaking conversation back and forth? Pretty silly stuff.
And yet, it's such a good thing. We're telling them we love them. It feels good, both to express that love and fondness, and to hear it, even if the words aren't fully understood. And when our pooky is someone who can understand us, our spouse, our children, our family, what warmth and blessing and grace it brings to both lives.
Recently Death has reared his dark head again over our extended SCA family. Tragedies can be so sudden, so unpredictable, and take away loved ones without a moment's notice. Nothing will change the pain that those who have lost their loved ones go through, but we can all try to spend our finite time together in as rewarding a way as possible.
So, sing to your pooky. Tell your spouse, your friends, your children, your furry friends, how much you love them. Say silly meaningless things while you clasp them close, and never feel silly about it.
I'm singing to you, my friends, and I hope you all know how much joy, laughter, and wonder you all bring to my life. Be well!