How long from the time the pond had water in it until it was stocked? That bass went 3 pounds....how large would it have been to be physically carried by a kingfisher? I think that bass was already good sized when it arrived.
Accidental drops of a small, impaled fish that probably didn't survive....I can see that.
Pond started filling up in November and it was stocked late May.
Then the question is: can a small fish that can be carried by a Kingfisher grow enough from November to May (without any available food) to be able to spawn?
I do believe that a kingfisher could transport a small fish. I have seen them carry one away many times from my pond. Not that they knowingly stock a pond, but more like if one grabbed it from a pond, then flew to a tree over another pond to eat it and dropped it (Dang gone it! Now I have to go get another one...)
