Green Heron Found

I think you almost had a very nice shot of this bird. The light is soft, the habitat is good, you got a good pose just about everything works nicely except for the missed focus. You would improve your odds of getting a sharp picture big time by using a tripod or monpod and if handholding follow the shutter speed/lens mm formula that Rich mentioned. Personally I still have yet to see a green heron much less get a good photo of one.

A touch soft here as noted, good luck in Arizona Byron

Byron,

I usually saw Green Herons a bit away from the coast when I lived in FL, they seem to prefer fresh water to salt. Because of their coloration they can be challenging to see at times.

Your image is a touch soft some of that may be due to the slow shutter speed and handholding. In this case I would have bumped my ISO up to get a faster shutter speed with the camera set to auto WB and using aperture priority.

I don't use just one specific ISO or aperture when I am photographing bird instead I take the information in front of me, judge the available light, pay attention the bird's behavior (static or active) and determine what shutter speed I'd need to capture the bird in focus. Obviously with a subject that is still or slow moving you won't need an extremely high shutter speed (unless the bird is on a moving object of course).

The other issue I see here is the proximity of the vegetation to the bird, the mangroves are touching the heron and occupy a great deal of the frame. If the heron and mangroves would have had space between them f5.6 might provide a nice background with the mangroves sufficiently oof.

Since the mangrove leaves are so close to the heron in this image you would want to get the majority of the mangrove leaves in focus by using f9 to f10 (use the depth of field preview button on your camera to check), that would drop your shutter speed even lower, so bump the ISO up until you get enough shutter speed.

Have fun in AZ, looking forward to seeing the images you get there.