Wildlife will always find a balance...when an area has too many of one thing then they will either move on or not breed so much. What is the point of bringing young into the world if they have nothing to feed on.
The trouble with man is he is driven by wealth, hen harriers kill game and that is money to estate owners. I had a conversation with a landowner down here in Cornwall who was trying to keep me off his land, even though a footpath ran right through the middle of it, At one point he started telling me about all the buzzards he had killed because they were taking the pheasants...Buzzards had nearly been wiped out in Cornwall by the end of the great war...at the time rabbits were a valuable food source....now we rarely eat rabbit, there are plenty of buzzards, there are plenty of rabbits and nobody cares because money is not involved...whereas with game birds...£1000s can be spent in one day by rangerover owning tossers just out for a days sport....we can't have one hen harrier getting in the way can we?

Mr H