Here are a couple sketches I did after practicing sparrow skulls and skeletons. These are from reference pictures. Learning the skeleton first allows me to learn where the skeleton fits underneath skin, muscle and hair/feathers. Then I practice, and I start to naturally memorise where everything goes. I have some anchor creatures from which. I base everything else. Humans are my anchor for mammals, so I just learn where everything is in relation to where it would be on a human. Birds are too different from mammals, so I need an anchor that is a bird