Here in Chicago, two municipal solutions to the city-wide rat problem are (I am not making this up):

1. Coyotes, which are now a protected species in the city.

2. Installing a large colony of alley cats in your back yard. The city has a program to supply them ready-made.

Perhaps there is a charm to attract rat predators.

I know there are rats in the neighborhood, but they seem content with chewing open and raiding our trash bins.