Hi Pete,

I reckon that what you were hearing was a slow creaking. A creak is not just any old sound, but a (usually) super-rapid succession of pulses. Slow it down and it becomes a slow succession. Now, when you tighten a wire passing thriugh a number of staples in wood or the like, there is some slippage that causes creaking. It stops after the wire stops slipping intermittently over the wood.

In your current weather (funny! It's quite warm round HERE... Crazy Irish! Me, I just blame it on global warming... <mmbl... mmbl...>) the contraction of the wire as it cooled caused increased stress and creaking. No doubt had you been there when the temperature changed rapidly, you might have heard clear creaks. But, especially with so many posts having to accommodate to each other's stresses, it slowed down without actually finally resolving the situation, and you are hearing the residual adjustments.

Of course, not being there in person etc... YMMV and so on.

Cheers,

Jon

I suspect that Jon is correct but with a slight twist. The barbed wire is stranded and as it contracts the twisted strands will tend to untwist as the tension increases. A good way to investigate is to borrow some nail varnish from your wife and paint a line of it over the wire where it passes through a staple. Do this during the day and then take a look at it as it cools of at night. You will be able to see the varnish cracking and will be able to tell if the wire is either slipping through the staple or twisting.