Not exactly their niche. They might hunt for insects, but it won't be enough in terms of energy acquired. So probably they will reduce in population until rats'

Not exactly their niche. They might hunt for insects, but it won't be enough in terms of energy acquired. So probably they will reduce in population until rats' population will restore back. And its good to keep rats busy. They won't wander as freely as they do now and hence eat less insects.