Feel like I'm starting to lose my mind with this one.

I'm regularly hearing a noise in at least two rooms of the house, which I can best describe as a creaking or clicking. I've listened to recordings of deathwatch beetles and it's definitely not that. It sounds almost exactly like a door creaking gently except very faint.

When present, this noise repeats in intervals of about 5 seconds. It's barely audible, just on the edge of hearing – so much so that it's almost impossible to pinpoint it to one place. I've tracked it down to above one of the cupboards in the kitchen, behind a set of shelves in the study (possibly IN the shelf) and bizarrely, an old box of tea bags.

That last one is what really throws me, but I'm 100% sure. The box was on the counter, and I was able to put my ear right up to it, and the sound was very pronounced. I was sure it was some kind of audible woodworm or something, but now that I've found it in a tea bag box I'm unsure. I emptied that tea bag box and found no bugs or insects.

The sound appears to be organic in nature, because if I make a disturbance in the area, the sound stops. In the case of the cupboard and shelves a sharp bang or shake, in the case of the tea bags I just lifted the box.

I have quite sensitive hearing and my wife can't hear the noise. She's starting to look at me funny when I talk about it. The only recording equipment I have is my phone, and that's not sensitive enough to pick it up.

I'm going to see if I can find an old laptop with a mic port and record it next time I hear it, but until then has anyone got any ideas what this could be?

NOTE:

It's definitely NOT a mouse. I know what a mouse sounds like, and there was no mouse in my box of tea-bags. This is something much, much smaller. Something small enough to live inside cardboard.

Update

finally managed to capture the noise on my phone. apologies for the low sound quality. There's a lot of background noise from just the electronics in the phone. The house was completely silent last night.

https://soundcloud.com/roryok/weird-noise

You'll hear it four times in all. I've edited the track to reduce the waiting time, but the sounds were about 20-30 seconds apart

Update 2

I've since found out the bugs are called "paper-lice" and are quite fond of eating cardboard / paper (hence the name). No idea how to get rid of the little buggers but at least I know I'm not going crazy.

Here are two photos of the bugs in question:

The two giant yellow things are popcorn kernels!

zoomed out slightly, so you can see the scale properly. These guys are tiny