Warning: This is no National geographic video.
I suspect that many don't quite get this "whiffling" behaviour presented here
. ...and you still may not after viewing my poor video below.
for still photos and a description of whiffling. BTW ... quite a few folks here watch birds and ducks do this as well...they fly so damn fast though. Ill never photograph that.
At about 13 seconds in the video watch the goose in the upper left corner
. It will flip upside down and drop fast. Don't blink as you will miss it. Then right after that, two geese to the right of the first whiffler will do the same. It is fast.
Again, watch again that first bird at 13 seconds. See how fast it falls. But it is still in amid the flock so one wonders why they do this. Interesting that the first bird to do this ends up near the front of the pack.
BTW...Nothing else happens after 25 seconds in the video. ☺Brief description of what you are seeing (from my web page):
Ducks and geese will dropping into a pond by twisting and turning as they come down. This is called whiffling. When I first noticed whiffling, I assumed they were merely twisting sideways to lose "lift" and allow them to drop faster. I was surprised when I took some pictures a few years ago and saw that one or two birds were completely upside down. Interestingly, their heads were upright. When they slip sideways, they indeed lose lift, but when they turn upside down, there is actually a downward pull (Bernoulli in reverse) and they drop fast for a fraction of a second.