Very efficient about it, was our Toshi. Five seconds of scuffling in the frozen twilight, max, and then Tosh bounded onto the back porch to deposit a still-warm (but, thankfully, no longer twitching) full-grown rabbit at my feet. If I hadn't slammed the door fast, he would have carried his trophy inside to decorate the house.
ICK ICK ICK ICK ICK ICK
On the other hand, I can't help being impressed by the skill it takes for a spoiled couch potato of a dachshund-mix to (a) sneak up on and (b) execute a rabbit half his own size. If I met a rabbit half my own size, I doubt that I would decide to, you know, attack it. ;-)