Target areas with a lot of bobcat sign like fresh scat and tracks. They sometimes will have a toilet area, usually in a sandy place, just like domestic cats use a litter box. if you find one of these and the scat is fresh its usually a good place to call. Here in southern AZ I find a lot of bobcat sign in sandy desert washes.
Most cats I've called have shown up around the 15-20 minute mark.
