Where are all the Leverets?

This spring Derek has been ploughing ground in preparation for planting peas over the next few weeks on the brash land at the top of Bredon hill. He commented to me earlier in the week that he hasn't seen many leverets (young hares) this year. Another comment he made was that he was ploughing in the warren field, which is about 50 acres and he was being followed by 21 Buzzards, yes you heard me correctly 21!! That is just over 1 buzzard to the hectare. I think that there might be a link between the two. Obviously the buzzards need to feed on something, were they being attracted by the thoughts of juicy worms, I suspect they were when we are ploughing but what about afterwards? We know that there are fewer rabbits this year, (myxomatosis has killed a lot) so what else do they feed on, the odd vole, or mouse maybe a rat or two but I suspect that a nice young leveret in the middle of an arable field makes a much tastier and easier snack. When do we draw a line under some of these species and say right, we need to start managing them before the balance is turned too far in one direction or another?