So I had a Great Blue show up on my property for the first time in the 4 years I've been working with ponds outdoors. It cleaned most of the goldfish out of my goldfish pond and was watching the koi pond. I'm still not sure if it got any, but it is what it is. I have not seen it for the past three weeks now. Could it just have been migrating through my area? If so, will it come back next year on its migration path, or do they change migration paths?