Major opted to grab a couple of pieces of jerky-ed mystery meat, which he rips a piece off of and begins to chew as he draws closer just in time to see her cross out a doodle of what appears to be a birthday cake. He chews thoughtfully for a couple of moments while his brain catches up with everything, eyes slowly going wide like that sloth in the Zootopia DMV scene (which Major's never seen in its entirety; he'd only seen previews for it).

He points to the birthday cake doodle and taps it a few times with his finger.

"Wait a second! Is it your birthday today?!"