Lost brown and white gerbil named Nibbles that escaped into a neighbor's yard in Green Bay.

I lost my little gerbil, named Nibbles, while taking him out for some fresh air in the backyard. He escaped from his ball and went under the fence into the neighbor's yard. We’ve been searching for him all afternoon and I'm really worried. He’s mostly brown with a white underbelly and very friendly. Please help me find him!