You can always focus on the squirrel-resistant types of bulbs - narcissus, alliums, fritillaria, winter aconite and hyacinths are all toxic to some degree or another and squirrels avoid them. If you like crocuses, the tommies (C. tommasinianus) have a reputation for being squirrel-proof also. Otherwise, it may be beneficial to cage your bulbs before planting - just layer the planting hole with a fine gauge chickenwire, place the bulbs and draw the excess up and over. The bulbs will grow through the wire but be protected from critters.

Daylilies are not a bulb but a fleshy rooted perennial - I've never had squirrels bother them before. Are they eating the flowers (very tasty, btw) or digging and eating the roots? I've not had squirrels bother true lilies, either.

Squirrels are especially nosy in my gardens. They would dig up anything newly planted and bite off the bulbs...daff, tulips, colchicum...as well as anything green that comes through in spring. Rabbits also bite off green shoots. Caging is not an option because my garden it tightly planted. I usually cover newly planted areas with chicken wire. It can be removed after the soil has settled or frozen. Bloodmeal also deters these rodents. I sprinkle it around new shoots in spring. So far, it has worked well for me.

Covering with the chicken wire does keep squirrels out after planting. I always remove the chicken wire in early spring. I guess I have found my squirrels don't bother the bulbs once they have been in the ground for awhile & the soil hardens over them. If planting just a few bulbs I will sit a 5 gal bucket filled with water over the planting & once the soil hardens the squirrels will leave the area alone. I have seen squirrels watching me plant the bulbs so I always cover. I say the squirrels in my yard are stupid because of the crazy things they get into but I have found that after bulbs sit in the soil & the soil hardens the squirrels go on to other things. One thing in my favor is my yard is filled with old nut trees that where here when we moved in so the nuts keep them busy.

I did the chicken wire thing today for some tulips I planted but mostly I put rocks over where I plant the bulbs. This does seem to keep them from digging them up and also reminds me where I have planted. I remove the rocks when the ground starts to freeze (or next spring for those I forgot). I admit this might be just an easy solution for someone a ton of rocks like me. I have also brushed leaves over where I planted some and that seemed to hide the newly disturbed dirt. I think maybe watering the ground to give it the appearance of being undisturbed might also help. I agree with mamoo....they are watching me in the fall. Such little jerks.

We use blood meal. Works like a charm. We sprinkle it lightly a second time after a rain or watering. We don't find that 'squirrels' are a problem (we like them) as much as every so often an individual squirrel seems to be a bulb nut. If one of these 'delinquent' squirrels is about we sometimes cover the planting with an overturned plant saucer for a couple of days to add further deterence.

I agree with an above comment that 'disturbed' dirt is a big variable. Perhaps squirrels associate disturbed dirt with another squirrel or other animal having buried a tasty treat.