When will people ever learn that the answer to most problems with animal or insect pests is NOT to import some other species of animal or insect? (Haven't they listened to "There was an old lady who swallowed a fly"?)
Like many urban areas, Brooklyn had quite a problem with rats. Then someone had the bright idea of bringing in and releasing possums. This was based on the theory that the possums would eat the rats. Great solution, right?
Wrong! The possums didn't eat the rats. Instead, they settled in right alongside them and joined them in feeding on garbage. and on fruit trees. So now Brooklyn has a problem with rats and possums.