'Gallowayfarm' who writes the excellent Working for Grouse blog has paid a visit to Geltsdale - and his comments make interesting reading.
"Birches and alders had been totally overgrown and killed by dense forests of ferns, and several young trees looked decidedly weak and ill, having been smothered by previous years of bracken growth," he writes.
"When compared to the hills around Teesdale, Geltsdale is utterly devoid of birds... It clearly is an excellent place to be a raptor, and it was hardly surprising to see that black grouse numbers were recently described as being less than a third of those found on neighbouring estates."
I'm sure there will be plenty of people telling me he's got it all wrong. But it's worth remembering, before we can judge the results of conservation work (or the lack of it) we need to decide what "success" will look like.
And whether you're a grouse keeper or the RSPB, it seems that predator control is a vital management tool.