This reminds me, I've seen crows divebombing eagles in mid-air. I've also witnessed smaller birds (starlings, I think) divebombing crows in mid-air. Why is this? And why do the larger birds seemingly tolerate it without counter attacking?

The smaller birds drive larger predator birds away from nesting territory. The larger birds can’t attack in flight.

It is fascinating to watch, but also a little disturbing because it appears that it's done with intent to injure at times.

Cool

Do they carry a camera everywhere? How many pics have they taken to date? Do they have other amazing shots?

They wait a lot, and they take a lot of pictures.

And after all that, there's luck.

I have asked people who are nature guides (and spend all day out in nature) if they've ever seen certain birding behaviors- and they've only heard of them.

I had no idea there was a competition like that. Jack Black was a delight.