Be interesting to know facts. There's very few where I am, infact your very lucky to see even one but in larger numbers I'd imagine they could make a dent in the rabbit population. They love a rabbit.
Never see them where I live mate, worked in Bracknell for 6 months and we would see them every day, a lovely looking bird... Never seen big numbers together and from what I understand the big gatherings you see are around he feeding stations... I'm sure they would take a few rabbits but couldn't see them making a big dent in the population.....
Maybe not... Someone surely knows. The only