Frowning: One moment baby can appear content, and then loses eye contact with you and looks away. There may be a definite frown over the forehead and eyes.
Clenched fists: Baby’s hands are no longer open and relaxed but are clenched and tightly closed
Hand to mout action: Baby can end up scratching his/her cheeks or eyes, when what he/she is attempting to do is suck on a finger or thumb in order to comfort himself.
Jerky movements: Especially with arms.
Yawning: This is the most obvious tired sign. If baby yawns then baby needs to go straight to bed. Yawning is the result of a low oxygen intake and the body responds to this by yawning.
Grizzling: This starts out on a low scale and then proceeds to full on crying. This cry can sound like a growl.