In reply to Ben87:
Langholm is an anomalous example. In addition, diversionary feeding remains a controversial side of this management. Is it really right to leave out food for a wild bird, which by definition, normally, hunts for its prey? However, in the bigger picture, it is better to be arguing about this, rather than the unknown causes for the disappearance of 5 male Hen Harriers this year.
I have no idea if it is the actions of a minority of gamekeepers or common practice, but a number of examples could be given which paint a different picture to yours. When Hen Harriers were showing signs of nesting on a Cumbrian estate this year, the gamekeepers were reported to be out firing propane gas guns to discourage the birds from nesting on the land. Not conservation by any stretch of the imagination. Given the number of cases in recent years of poisoned Golden Eagles, shot Hen Harriers, buzzard trapping, we should ask why does this continue? I suspect the answer is similar to your response of "pressure from above". At the end of the day, as you point out, it is a business (which I acknowledge, helps local communities from an economic point of view), so if estates have to rear twice as many Grouse because they get eaten by predators, this is reducing profit. But also, probably another answer is it seems to be a crime that doesn't carry a heavy penalty, so the consequence if caught, appears to be not that great.
http://www.theguardian.com/uk/2007/nov/07/monarchy.wildlife
In Bowland, there always seems to be a new hut or grouse butt being made and the tracks continue to get better. Hardly something I call natural or wild. I also believe that pheasants get burnt rather than eaten on many Bowland estates, not taken "...home to share with family and friends". I should also add I'm not vegetarian and have enjoyed Red Grouse when I have bought it on the odd occasion.
However, I also realise that many arguments can be turned around. The RSPB feed Bitterns fish at times during winter. At Leighton Moss there was a deer cull this year to control the population. All this is management of the land to encourage certain species and discourage others, the same as gamekeepers are doing.
So, I acknowledge that this is an incredibly complex topic, I haven't really decided where my answers are. I also think that more examples like Langholm are needed, showing that estates can support Hen Harriers. Instead we have Ian Botham and the RSPB constantly arguing.
I think it is time to look at if it is best to drive up a moorland on a newly made track, shoot 200 Grouse, then go home?