Former Apple employee Richard Williamson has been hired by Facebook, reports Bloomberg. Williamson, who was in charge of Apple’s iOS mapping team, was fired in November after Apple Maps faced extensive criticism for its poor performance.Williamson joined Facebook in the past couple of weeks to be a manager within its expanding mobile-software group, said two of the people, who declined to be identified because the information isn’t public.Facebook has acquired several other Apple employees in an effort to improve and expand on its iOS app, which was updated today to add the Chat Heads feature.Other former Apple employees brought in by Zuckerberg include Greg Novick, a former iPhone manager who helped develop the device’s touch interface; Mike Matas and Kimon Tsinteris, software designers who joined when Facebook acquired their company Push Pop Press; and software engineers Scott Goodson, Tim Omernick and Chris Tremblay.Facebook has also reportedly hired former Twitter employee Loren Brichter, who designed Twitter’s original iPhone app and popular word game Letterpress. Brichter is a former member of Scott Forstall’s iPhone team.