JimmyM,
Could have been anything from a red tail to a coopers to a goshawk. Keep in mind it could have also been a great horned owl as well. Rabbits are easily handled by any of the above.
The crow is a different issue altogether, as I've seen them attack other raptors and then see the raptor catch it, almost accidentally, while flipping upside down to defend itself. With that being said, who knows, birds surprise us all by what they do each and every day.
Cases in point a great blue heron I saw fishing a drainage grate beside a frozen pond, and a kingfisher perched on a low bush/tree fishing a stretch of unfrozen river about 25ft long next to Pearson airport.