After finding, what turned out to be squirrel scat in my attic, I set a live a trap to catch the animal in question. I didn't know if they were caused by rats or squirrels, but my suspension was squirrels (I do research on rodents for a living). I will note that there wasn't a lot of scat, and I couldn't find a nest to speak of.
I have no problem setting killing traps, and I will set some out, but I'm wondering if any one has had any experience using the same live rodent trap in the same area with presumably the same population of animals? I'm wondering if the other squirrel stuck in the cage and therefore avoid it.
The reason I used a live cage this time was to have a fresher specimen to sac and preform a necropsy on (to check for pathogens I should care about for my family). I've already appropriately cleaned the scat where I found it with bleach. My reason for setting it a second time would most be to have one more trap up there (though I might do another necropsy). I would also vote up any experience with rats or mice.