They like to "fish" for their food and often get wet which requires a lot of drying out time. Even so, at "still" they move frequently to shift the feather layers - I guess to even the drying. These were shot with the Sigma 70-300 with 2x at 500mm 5.6 at 1/500 ISO 320.
Not bad shots, but they don't hold a candle to what Steve is showing with his heron shots. Oh well, something else to save up for.