The question was
" How do you pin point rats in creeks when not alot of signs are present? "
and you DON'T These sets are great sets for taking rats.Some another ones that I have used are.Setting a snare on a Log Toilet,The Artifical Feed Bed Set,The Artifical Slide Set.
But I took the question as if he was wanting to take rats in high numbers.To do that you nead a LOT of rats. And a LOT of rats make a LOT of sgin.