"jane" wrote in message
It's probably squirrels. They destroyed all my croci the first year I
was in the current house, and since then I've grown them in pots under
an inch-wide aluminium mesh. They don't get through that. Ditto for
tulips.
The pots of exhaused corms which I've buried in the garden to recover
in the past don't get noticed. I think they see freshly moved soil and
wonder what's buried there.

I do suffer predation by grey squirrels. They strip over 99% of my walnuts
while still green and growing in late summer and - more amusingly - after
the crows (jays) plant acorns in my lawns in early autumn - often grey
squirrels will come within minutes to a few hours afterwards and remove many
of the acorns recently planted by the jays ( thankfully reducing the number
I have to root out myself ).
However , the squirrels round here do not seem to appear at night-time and
certainly wouldn't get bulbs that have been buried under a 3ft x 4ft steel
sheet with 50+ lbs weight on top !

Although I have heard and seen badgers raiding my patio pots for tasty
extras, the current problem with crocus theft is evidently attributable to
small mice.

Last night I put a mouse trap in the most theft-prone area and was surprised
to find one dead mouse this morning. I would much rather train the mice
not to take my bulbs, but they seem undeterred by 'scent off pellets'
mustard powder or other deterrants so far tried.

Anthony