As we all know, Pinkerton had no intention of catching and/or devouring the kitten. He was only watching out for it's safety.
Although it may be too big, you never know how nasty a magpie might be. One could fly through the door at any moment and swoop the little critter away.
Pinkerton quickly directed the baby back to its hay bed and asked it to stay hidden for a few more weeks.
Good boy, Pinkerton! :)