No one covers it because there's no transparency so reporters can't find out anything.  City doesn't keep detailed enough records of its finances.  It needs to have the Council pay for an independent auditor, and the zoo is politically protected from that happening through its wealthy and politically well connected benefactors.  Used to be that the zoo keepers would talk, but don't know if that's the case anymore, especially now Santos is in charge.  It's much easier to keep doing fluff pieces when the zoo publicizes something, so that's the vast majority of their news coverage.