I'm thinking that these tunnel traps are mainly in use during the nesting/rearing season when predator control is best practised. I only run my trap line from 1st March to 1st Sept, then traps are lifted, either this keeper has sprung them because he cannot inspect them every day through the winter or he's got a do gooder wandering aroung springing them .
think your right. will be the keeper we fired ours when we could not look every day