Guessing it was a shutter click while rotating the zoom. I have a buddy that does some similar abstract stuff.

Ducks are tricky, but quail can be down right hard. They are a quick bird and hard to grab a focus on. Fast shutter with multiple bursts is a must. Quail like to stay low too, so pick your background (wisely and safely) before the dog/hunter goes to flush. Ducks are downright fun. A good 70-200 is a good choice for them in a blind. Watch the position of the sun. The hunters will get upset if the reflection off your lens starts flaring birds. If you are a Facebooker, I highly recommend checking out Ted Wells, Luke Cruze and Nicole Belke. Excellent waterfowl photographers.

FYI...Right now, the G2 Tamron 150-600 is $1099 and includes the tap-in console with free shipping. Both Canon and Nikon mounts. Buydig on Ebay