Mary wrote:
>  I thought only domesticated ones did it because they are not really hungry,
> they get their Friskies or if they are lucky, their paleodiet.

I think it is to hone their stalking and hunting skills. They give
every
appearance of enjoyment while allowing the mortally wounded prey to
think it has a chance of escape before catching it once more.
Adults seem to give "partially killed: prey to their kittens or to
humans if they seem to be less skilled at hunting [vegetarian owners
seem to get more 'presents' than meat eaters]

Alison