I have never used the commercial scents and although they have their uses, I don't see my ever carrying any in my BoB.

I trapped Nutrea Rats when I was younger, using single and double spring traps. Scent was never a problem in that environment but killing the animal without cutting the skin was a sometimes laughable scene to watch. I usually ended up half wet from trying to hit the water type creature with the flat side of an axe, usually getting a lot of water on me (in the wintertime).

I have trapped birds using the old cardboard box, bait, and string system. If I were in the woods, I would fashion a latticework box of branches, probably use bread or cracker crumbs to get the birds into the trap.

You can use a similar, more complicated version for trapping fish in streams. The trick with a fish trap is to fashion a conical entrance that will prevent the fish from finding their way out of the trap. Then check the trap daily. If after a day, you don't have fish, recheck the entrance to the trap, if that still looks good, then move the trap to another location. You have to make some latticework "walls" to run from the trap entrance outward for the fish coming by to see the wall and then they follow it to the entrance, go inside of the trap and then they fail to find their way out of the trap. Seine netting is often used to form the walls on "Buffalo Hoop Nets" and they run 20-30 feet out from the "Buffalo Hoop Nets".

That's been my experience, except for using crab and crawfish traps which are much like the fish traps except for shape and mesh sizes required to hold the crabs and crawfish.