Pete Wentz Bronx Mowgli Studio City

Pete Wentz and his adorable son Bronx went on an errand run in Studio City on Saturday, and the week before that the 4-year-old traveled with mom Ashlee Simpson and the rest of her family to Hawaii for Christmas.

Ash is back in New York City, and we know she's working on her upcoming fourth album, but since she's split from beau Vincent Piazza, we have to wonder why she's so far away from her little boy! Why not move back to Los Angeles? We know Pete loves being on daddy duty when he's not hanging out with his hot young girlfriend, but we're guessing Bronx misses mommy!