Birds can drop fish after they've captured them. Not longer than a year now, we were visiting my wife's family, and me and my father in law got to Walmart there was a dead fish in the front, but when we mentioned it to my wife who got there before us (separate cars) she said it was struggling for life when they saw it, I don't think there was a lake nearby enough, but I wouldn't be surprised if birds have accidentally introduced life into new bodies of water.
More likely is that birds move fish between bodies of water because of fish eggs they carry on their bodies. This is how most bodies of water become supremely populated in Texas. In Texas all ground water sources, other than 1 lake on the far east side, are created by people in recent decades and almost all of these bodies are full of fish that did not get there on their own.
" This is how most bodies of water become supremely populated in Texas. In Texas all ground water sources, other than 1 lake on the far east side, are created by people in recent decades and almost all of these bodies are full of fish that did not get there on their own."
I see Texas multiple times and Norway zero times. What is the confusion causing your question?
Yeah, but at least two live fish (a male and female) being dropped into the same remote lake, then finding each other at spawning time seems increasing implausible. Never say never, but ...
Apparently some fish species do have small sticky eggs that can stick to the legs of water fowl, or even (with very small probability) pass through them intact, so this seems much more likely. Maybe a group of ducks feeding in one place then flying off to another?
"Yeah, but at least two live fish (a male and female) being dropped into the same remote lake, then finding each other at spawning time seems increasing implausible. Never say never, but ..."
It just needs to be one pregnant fish. (or many eggs)
Interestingly, it is not always the case that birds can drop what they catch. I never knew this until I watched an eagle struggle to shore after it caught a fish that turned out to be too large for it to fly off with or do what it needed to do to be able to release the fish until it got to land. I have no idea about the swimming ability of an eagle but they certainly can't swim when they have a large fish in their claws, it was quite the struggle for that eagle to get to shore.
They don't need to be on the ground to release as a rule, there are just situations which make it very difficult or impossible for them to release without being on the ground. The bald eagle courtship would be suicide if they could not release while in the air. For light loads they are quite good at releasing stuff in the air and will pass nesting materials and food to each other while in flight.
