Gray cockatiel with yellow crest

Hey, I lost my gray cockatiel yesterday around 5pm. He has a bright yellow crest, orange cheeks, and a gray body with a white-tipped tail. There's a small red leg band with the code A12 and a tiny white patch on his left wing when spread. He’s a friendly little guy who loves sunflower seeds and mimicry; he often responds to his name and will step onto a finger if you coax him. I last saw him along the Missouri Riverfront walking trail behind the South Dakota State Capitol on Capitol Avenue, near the Pierre Historical Museum and the pedestrian bridge by East Dakota Avenue. If you find him, he’ll probably chirp at you and come closer for a snack. This bird means a lot to me—it was a gift from my sister and I’m really hoping to get him back!