Sky whales...fun idea. Whales need literally tons of food to survive and when you add flight to their energy requirements, well that's a lot of birds!
Anyhoo, you already know everything that's good about this painting - and once again, props for working with traditional materials - so let's get on to the other stuff.
You could do more with atmospheric perspective. When I saw the thumbnail, all three whales looked like they were in the foreground. The sky looks flat too. Some sort of color shift will probably help, along with changes in the size and texture of the clouds.
That's it. Keep 'em flying!
First off, thank you SO much for taking the time to critique!! I really appreciate that! (:
Thanks for bringing the depth perception issue to my attention--I need a lot more work with that. The clouds are pretty flat, too. I think some skyscape practice is in order.
That would be a lot of birds! If you're curious on their diet, Asera is a mostly insect-based world, most of which are on a slightly larger scale than earth insects. Baleen sky whales feed primarily on insect swarms. Prehistoric sky whales like these, however, are the only sky whales which feed primarily on other sky whales (or people and livestock, on the rare occasion).