The Nikon D500 Does Tree Swallows! - 17 Jul 2016
Group Autofocus is supposed to help maintain tracking efficiency when birds pass into areas of busy backgrounds (foliage) and I have to say, it did very well once locked on. The trick is getting the birds locked in... It worked much better w/ larger subjects. But be forewarned, Group Autofocus focuses on the closest object, so its easy to lose eye-focus when a wing flap occurs. I noticed this yesterday when an Eastern Kingbird was perched on a tree - even though it was centered in the camera the focus was on a branch sticking forward. So, now I have the front camera function button set to Single-Point Autofocus for birds in denser foliage.
I can't believe how much fun I'm having w/ this camera...