On 11/07/2015 6:02 AM, Adam Funk wrote:
We've had a mouse living in our worm bin for a few weeks (I've seen it
dancing around on top of the heap when I tip stuff in).

The bin is the open-bottomed "dalek" type. I have one of those oblong
metal box mousetraps with two one-way gates one side & two spring
traps inside, arranged so that a "flag" is visible through the top
when a trap's been sprung. I originally put this down under a nearby
wall of the shed (the shed walls have ventilation gaps of 40 to 50
mm), assuming that the mouse would run that way; after a while, I
moved it under the wall closest to the worm bin.

I now wonder if the mouse is living more or less permanently inside
the bin --- is that possible?

Yes. Mice burrow in and under my kitchen compost type bin which looks
like one of these:
http://www.gardensonline.com.au/Shop...Show_5049.aspx

I suspect your worm bin might be similar to my kitchen waste compost bin.

Since I live on a farm I have mice burrowing in lots of places Like
under my big square bin compost heaps and in and around anywhere that
there is any sort of animal feed. Mice are more active in Spring and
Autumn and they never disappear. It's just a matter of constant war and
reducing numbers.

I actually like having mice in my Gedye bins as they are great turners
over of stuff that goes in there and there constant turning works to
reduce stuff into good garden bed additive. I only do something about
mice in my bins when the numbers build up too much.

I'm reluctant to put any kind of poison in the worm bin since I use
the output in the garden & (when I'm lucky) grow something edible.

I'm seriously considering setting the trap-box on the top of the
contents of the worm bin. Is that a smart or stupid idea?

It's a smart move. I've used one of these, baited with a glob of peanut
butter, placed on top of the detritus in my bin and caught 8 mice in one
night:
http://www.sound-ai.com/Small-Multi-.../pd_1_4529.htm

The problem with mice is that they are smart and once you catch a lot of
them in the trap and dispose of them, the next lot won't be caught again
by the same trap for a few years so varying traps used is a good idea.

The only way I've found of excluding mice form worm bins is to use the
closed system worm bins that are not open in any way and which have a
lid. Even then I've found mouse gnawing marks on spots where mice ahve
been able to get a purchase and they've clearly tried (but thankfully
failed) to get in.

These are the worm bins keep mice out:
http://esvc001654.wic004ty.server-we...es/Page600.htm