How do mice get the bulbs out so neatly?

Do they nibble them in situ?
Do they put the soil back to keep it nice and tidy?
The only clue I had that anything was amiss was small indentations in the soil.
Foxes and squirrels leave a mess so at least you know there's no hope.,

And why don't they eat th Spanish bluebells?

 

Because they are devious little so & so's

 

Bluebell bulbs are poisonous and bitter tasting, so generally avoided by mice. (They’d probably give up after the first couple of feet anyway .)

 

I give up when I get down to my elbow. @Plantminded

 

I think the mice get them out whole and take them elsewhere. I often find I have empty pots. But sometimes they replant - one year my broad beans turned up sprouting in the spring in arbitrary other pots!
My main complaint is when they nip off seedlings and just leave them when they don't like the taste.