I found a slight (OK, considerable) increase in rabbits when I put down alfalfa. We don't have deer reincursing around here just yet, but that shouldn't take long. I expect to see a few when they do.

On the other hand, I live right in the midst of the third-largest citified area in PA. Our critter count isn't that high.

You should notice an increase in birds, lizards, and toads. Maybe they'll scare the deer away???

It seem intuitive that you would have an increase in pests, but usually it doesn't happen. We had rats, tree rats (squirrels), possums, raccoons, and skunks when I first started using corn meal, and there was no apparent increase in their population, nor any inordinate attraction to our yard. Now we have cats so there are no more rats or squirrels, but unfortunately there are no more birds, lizards, geckos, or toads either. Give and take.