Cockatiel with yellow crest, orange cheeks, blue leg band

I lost my cockatiel yesterday around 3pm near the Starbucks on Main Street in downtown Chico. He's a small gray bird with a bright yellow crest, orange cheek patches, and a blue leg band marked A12. You'll notice a tiny white feather on his left wing, and he tends to chatter when he’s excited. This bird has sentimental value to my family—it was a gift from my grandmother, and we’re really hoping to have him back.