I've used this a number of times and I feel it seems like a hit or miss. I have four bait stations distributed properly in a very small area and the varmints seem to avoid them because I check if they've eaten what's inside.
That being said, maybe they ate just enough because in the past few days I haven't seen them... Is it the heat or did they meet their demise?! I will listen for their chirp sound and if I don't hear it we will know their fate!
bought a canister at tractor supply yesterday and put some pellets around the burrows. they are eating this stuff up as fast as I can replace it. however, we'll monitor the the squirrel activity to see if it really puts an end to the squirrel problem.