Some very nice shots Dave!
No one should be afraid to try wildlife at high ISO values. You can often get very nice shots even as high as 6400 if you need the speed to get them.
I shoot mostly Tav and find it perfect for getting the best speed in low light. It does tend to overexpose in Tav but you can back off the exposure by -1 and it is usually just right.
Almost all my bird shots are at high to very high ISO settings. Up to 3200 is typically no problem to process...beyond that it is iffy, but sometimes you get a really nice shot as high as 6400. It's always worth a try! If you don't try, you get nothing!
Birds...my yard and woods are dark, so high ISO is a must.
https://www.flickr.com/photos/129469263@N03/albums/72157651162955781
Regards!