Pico, the youngest of the cats, has taken to bringing in fallen crabapples (from the World’s Tallest Crabapple Tree TM) and leaving them as presents for us, in the way that other cats bring dead birds/mice/etc. Our current theory is that she’s seen us eating apples, assumes that the apples she finds outside on the ground are of the same ilk, and is trying to give us something we’d like.
And on top of that, the one cat who does kill birds (Boingo) never brings them inside, but generally buries them out in the yard.
Weirdos.