Even if you did relocate/kill these animals as soon as the territory was free another preditor would take its place. I would be a never ending cycle. I have a similar problem with kookaburra's but after one or two fish were eaten they realised that they had to stay at the bottom of the pond unless I was feeding them, I also added more plant cover for the fish. I have not lost a fish in three years. I cannot believe that anyone who loves animals whether wet or dry would even consider killing another species. Protect your pond yes but their are other ways surely.
