Rats are very suspicious of new items in their environment. Many years ago
there was a long interesting article in National Geo about rats.

I'm not sure where I learned this technique but it REALLY works, my son says
it's not fair.

Whenever I've had to trap rats I used a spring trap (Victor).

The key is to bait the trap (I use peanut butter) but DON"T set it.

I do this for three or four nights. After giiving the rats 3 or 4 free meals,
I bait and SET the traps. By this time they are no longer wary of the traps.

The first time I used this method I caught four rats with six traps in one
night......the lot of them gone!

cheers
Bob