Golden retriever mix, red collar, lost in Chautauqua

Hey there, I lost my dog yesterday around 3pm. He's a medium-sized golden retriever mix, about 55 pounds, with a fluffy coat and a small white heart-shaped patch on his chest. He wears a red nylon collar with a black tag that has my number, and his left ear tends to flop over when he's excited. I last saw him near the library steps on Park Street in Chautauqua; he dashed after a squirrel and slipped into the side alley behind the Chautauqua Bookshop. He's very friendly once he knows you, but he's anxious around strangers, and I really need him back home—he's been part of our family for years and means the world to us.