Condolences on loosing Kassie Girl. They really do become not just part of the family but a huge part of us. Cockatiels are great birds .. and they interact with their "parents" like many youngsters almost. And they love to be handled... really
So far we still have Woodstock and Flip - a mated pair of Cockatiels. We have had them oh probably 10 years now at least. No younguns though - cage isn't big enough. They are a part of the family. I know how we felt when we lost our cats Black Paws and White Paws and then when we lost Spook. They truly are members of the family and their loss is profound.
Unfortunately, we have to find a new home for our birds. With my COPD and PF the docs say we can no longer keep them if I want to keep my health up. That is going to be hard. Like your Kassie Girl, Flip and Woodstock have taken over from Spook and are now our intruder alarm ...
Half the time we are not sure who/what/where that intruder might be
but they sure do let us know something is fishy in their world
Not sure how we will cope with that, but at least we will make sure that they find a loving home.
Time heals all wounds thankfully. Be well