I am cleaning out Hard Drives making room for new images and I came across some images from years ago when I was practicing a “panning effect” with a cooperative Great Blue Heron. These were taken early in the evening before sundown. The featured image and the one below were taken @ 1/50th sec. to get an interesting Blur Effect on mostly the water & some on the wings to show some movement on the subject bird, but more streaking on the water or background. Here I was using f/13 @ ISO 400. You basically follow along with the Heron and try to be as steady as possible to get a streaking effect in the water as you shoot at a slower shutter speed. This effect gives the image more of a “moving” look to the bird in the image and makes the background more interesting looking. You have to practice and see what shutter speed / f/stop works best for your use. It also depends on how fast the subject is moving. You basically set an f/stop that gives you a longer shutter speed, and still keep the subject bird somewhat sharp. You can look at your preview and adjust from there to vary the effect to your liking. It is also a matter of personal taste as to how much or how little the blurring effect you like. But on quiet days looking for subjects to photograph it can be fun to experiment!
25 minutes earlier than above images with a little faster shutter speed did not give as much streaking movement in the water.