EOS R5 Birds in canopy — blurry!

[catsongs]

Aloha from Honolulu,

Upgraded from a Canon 80D to an R5 to capture white terns in flight.

The R5 can take some mind-blowingly brilliant shots.

But...

But when the terns fly in and dance about above my head in the canopy, I get hundreds of well-composed blurry photos. Very frustrating.

I'm shooting TV with 1/1250 to 1/1600 shutter speed. Using the 70-200mm lens.

The problem is clearly the focusing. The R5 can't find something in the terns' plumage to focus on.

I've tried a variety of AF options, but no luck so far.

I'm attaching a typical (screenshot) of the type of photo that gets trashed!

Honestly, I think I did better under the canopy with the 80D.

Any thoughts would be gratefully received!

Cat

[catsongs]

Aloha,

Still curious what your approach might be to "keeping it simple" in complex shooting situations. 

Example: fast moving object, busy background, lighting issues, etc.

Mahalo!

Cat