Please answer a question about the following article about Chicago Cubs:

Another unofficial but much more well-known mascot is Ronnie "Woo Woo" Wickers who is a longtime fan and local celebrity in the Chicago area. He is known to Wrigley Field visitors for his idiosyncratic cheers at baseball games, generally punctuated with an exclamatory "Woo!" (e.g., "Cubs, woo! Cubs, woo! Big-Z, woo! Zambrano, woo! Cubs, woo!") Longtime Cubs announcer Harry Caray dubbed Wickers "Leather Lungs" for his ability to shout for hours at a time. He is not employed by the team, although the club has on two separate occasions allowed him into the broadcast booth and allow him some degree of freedom once he purchases or is given a ticket by fans to get into the games. He is largely allowed to roam the park and interact with fans by Wrigley Field security.

What is Ronnie known for to Wrigley Field visitors?
idiosyncratic cheers at baseball games