What is this wood stork doing?

Is he yawning?  Is he calling to a passing bird?  Is he about to cast a pellet?  Do wood storks even have pellets? 

I checked Cornell’s Birds of North America Online and they said of the wood stork, “No information on pellet-casting.”  However, wood storks eat fish so they might need to regurgitate fishbones.

I prefer to think he’s smiling for the camera. 😉

(photo by Chuck Tague)