I love the first post and think it would also do well in Black and white.
I know ime daft but still following the Tamron 150-600,while looking through flickr i found this from a D750 @ ISO 9000,dont think ime ready to go that high for birds but you never know.
https://www.flickr.com/photos/126499587@N03/20174226924/in/pool-2470447@N21/