I too have never shot a bird photo at iso 100. As I invariably use iso 640 or higher, on FF, APS-C and 5DSr, all of my photos must be unacceptable to Talys. Using the sunny 16 rule for exposure, a fully illuminated bird on a bright sunny day at f/16 at iso 100 would require an exposure of 1/100s, or 1/400s at f/8. A top bird photographer like Ari Hazeghi uses exposures of 1/2500s or faster at f/8, which requires an iso of usually more than 800 (see eg http://arihazeghiphotography.com/blog/how-to-set-exposure-in-bird-photography/) and goes up to 3200 or so on FF in poorer light. His work must be unacceptable too.
In fairness to Talys, he said *on the 80D*. But even so, I would push a camera like that to 3200 with no qualms.
Which is why I wrote I use 640 or more on APS-C and 5DSr. You can use high iso if you know how to remove noise with the right software and settings. If I use DPP or PS with bulk standard settings for noise then my 7DII and M5 are noisy at 640 iso, but there is no obtrusive noise when processed properly. If I was restricted to iso 100 I would have to give up bird photography. Base DR has never worried me because i am rarely down there.