Green budgie with yellow head; lost near El Paso Zoo

I let Pico, my green budgie with a bright yellow head, out for a little flutter yesterday around 3pm and he vanished. He's about 5 inches long with a tiny white patch on his left wing and a blue leg band labeled 42. I last saw him near the El Paso Zoo entrance on Paisano Drive, perched on a railing by the planters outside the gift shop before he darted toward the pedestrian bridge. He's a friendly bird and chirps when he sees people; I'm really hoping to get him back because he's been a gift from my daughter and he means a lot to us. If anyone spots him, please message me here; I will come right away.