Squirrels will chew through anything but metal; fabric or plastic may not work unless it totally disguises the planting.

I pretty much gave up on growing tulips in PNW. I live next to woods and with abundance of moles, squirrels, deer, rabbits and slugs something always eats my tulips and other susceptible bulbs. Now I grow most of them in pots and that seems to work best. I realize your tulips are already in the ground. I would place either chicken wire or plastic netting (sturdy) over the planted area to prevent squirrels from digging them out. I have no idea however how to protect emerging tulips in Spring. Maybe build a little tripod tents with plastic net?

We found the biggest threat to tulips in our garden was the voles, but virtually any hungry rodent will find them if they are hungry enough. Putting chicken wire over or around them may keep some of the squirrels out of them but it won't deter the burrowers.

Voles (field mice) don't hibernate and if you have tulips, they have a ready made food supply. We also found the solar powered rodent repellers helpful as well, although not 100% effective and triple the density that the manufacturer recommends. (If they say one every 75 feet, put one every 25 feet.)

After losing 3000 tulips that served as the winter buffet for a variety of critters, it wasn't lost on us that no one bothered the daffodils. When we replanted, we planted a mix of daffodils and tulips and that has worked quite well for us. We plant in clumps of mixed tulips and daffs throughout all of our beds. So far, we have lost precious few.