The best thing to do is to place chicken wire over the area where you planted the bulbls. The foliage will grow through, but the squirrels won't be able to get the bulbs.

I got a cat. That works quite well. While they don't catch the squirrels, they keep them away. But small mesh chicken wire doesn't require feeding, so that's probably better.

Around here I have moles- which also eat the roots off plants. So when I built my last raised bed, I laid out several layers of newspaper, then staked rat wire down over it. You might try staking down rat wire or something similar over your bulbs.