Check the area where you planted the bulbs. If your bulbs are no longer in the ground, they may have been eaten by gophers. Look for mounds of soil that have been offset at an angle from a hole. Gophers make short, inclined tunnels to the surface. They will eat tulip bulbs from underground or take them to their storage areas in their tunnel system.
Gophers are vegetarians and will eat bulbs, grasses, roots, seeds and tubers. They are most active during the spring and fall seasons and may consume up to 75 percent of their body weight in plant matter each day.
Prevent gophers from eating your bulbs by planting the bulbs in chicken-wire cages under ground. The cages will deter the gophers from getting at the bulbs but won't prohibit plant growth. Also consider planting daffodil bulbs, which most animals find inedible, near your tulips.