Culprit - mice or crows?

Today I noticed a group of crocus all nipped off just above the bulb. Very annoying as they were quite robust. Even though the bulbs apparently haven't been dug out, I'd blame mice. I don't think crows are stupid enough to repeatedly do something when there was no food resulting from it. Any opinions? And do you think putting grit would be enough to foil the culprit next time I plant crocus?

 

Voles......

 

@shiney - hmm, don't think it's rabbits, as they'd have to cross a stream to get into my garden from the nearest field. I thought voles are carnivorous @infradig ?

 

Oh dear @shiney !!!

 

I gave up trying to grow crocus some years ago. A combination of mice or squirrels thieving the bulbs, and sparrows or bluetits pecking the flowers made them a waste of time. It's a shame as they are a wonderful splash of colour at a dreary time of year, but unless they're planted in fine mesh baskets with a moggy in constant attendance, it's a no-hoper

 

Sparrow chicks get mine, but only the yellow ones. Blues are left alone.

 

Nope, just grasses and stems, normally just chomp out a piece and move on to the next. Particularly frustrating when they tunnel through a forest of bedding plants in trays, leaving 11 in a dozen.
They have little fear of humans, often sitting silently watching while you work, until one senses one is not alone.....

 

@infradig ah yes, I was thinking of shrews. I certainly have mice in the greenhouse, as they pinched the berries off the holly stems I left in there ready for Christmas. I'm afraid last year I trapped and killed quite few in there because they were damaging lots of young plants. But I'm sure there are voles around too as my garden backs onto fields and woods via the stream.

 

If the bulbs are intact and it's just digging it could be foxes or squirrels.
I have both digging holes in my garden, I think the foxes are looking for worms etc. and the squirrels just seem to dig for the fun of it.

 

It was too sludgy to check for the bulbs. It was just the neat way the leaves had been nipped off...