I think 99.9999% of fish swim their way into new ponds instead being delivered by air.
I think you probably right. However, the other .0001% can be a serious problem to pond owners that don't want bull heads.
I think incidental fish transferrals are ucommon to rare. Nevertheless, they are inevitable over time. Here's 1 of the most rare vectors, depending where you live. http://youtube.com/watch?v=cnweu5imNwE
I can't believe nobody has see 1 bird dive bomb another bird and force it into releasing it's fish. It happens millions of times a day, and I'm sure it happens while flying over unstocked ponds a few times a day.
Some ponds are so iolated they could go 100 years without being stocked. Yet I have seen 1 year old stump holes 300 feet from any water (or any possibility of flooding) with minnows in it.
