Dry stone walls

We're deep in dry stone wall territory here. Dry stone walls are the main field boundaries, and I love them.  

Good job really, as we have rather a lot. 

The one above belongs to a neighbour, and I noticed today that it seems to have been repaired recently. Ours, on the other hand, are looking a little worse for wear. 

This one is next to our drive, in what I'm now thinking of as the veg field, and it collapsed this week. We've also had a couple of collapses onto a nearby green lane.

This must have only happened in the last week or two as well. I wonder if it's partly the weather, and the sheer amount of snow that has been blown into drifts up against them. But they're also just old, and looking round I'm starting to see the places that are likely to go next. 

I've had a go at walling before, a long time ago. I can't even remember why now - I think I was doing some conservation volunteering at the time, and maybe it was part of a job, or perhaps there was a training course. At any rate, I have a (very) vague idea of what goes into building a wall. 

From what I can gather, it's basically a really big, heavy jigsaw, where you're not sure whether you've got all the pieces. 

I've ordered a book, and if that doesn't illuminate things enough, there are a couple of local courses I can go on in April. 

In the meantime, I was out until it went dark last night, stripping back enough of the collapsed stone so the wall feels stable again, and therefore is unlikely to fall on a passing rambler.