However from a conservation point of view putting this stuff down isn't always desirable (and sometimes they seem to be immune to it anyway!)
At one of our recent sites we have noticed some water voles. These are in decline in the UK and whilst have similar features to rats are no where near as prevalent and don't seem to cause the same problems.
Shooting at night here we have been careful to identify our targets, however there are so many rats that another method is needed.
This is a live capture trap designed specifically for rats. Should any other non pest get trapped, it will be released. Otherwise dispatch will be with a close range air pistol.
It is essential that a trap is checked everyday and is in fact against the law not to. It may surprise some to learn that it is also illegal to release a pest species once caught; you must humanely kill it. Releasing a pest in another area is not allowed and would cause issues.
At the same time it's important that your trapped pest must be dealt with humanely, drowning etc is not allowed.
https://basc.org. Have excellent advice on this.
Will report back on what we end up with.