My cats, while being allowed out, will actually come back in to use the litter trays; so I don't believe that cat shit in the area is by and large because of my cats. The number of birds in my garden would also suggest that the local wildlife isn't suffering too badly. I've had to put up with numerous complaints about my cats over the years, but it was amazing how they all but stopped when the Siamese who used to live down the street passed away.

By the way, as cats usually bury their crap it tends to be canine toxicara that is the problem.

Scott