You don't want them dead?
The only alternative to a cat and/or traps would be to wrap Wire mesh around the bulbs or plant them all in above ground pots.
At my house, voles also eat iris, beans, squash, watermelons, even pokeweed!
Also, Irish potatoes, sweet potatoes, and any vegetable seeds that I attempt to direct plant.
Personally, I do want those evil things to die!
And.... Apparently they taste so nasty that when the cats catch them.... They leave them lying around.
