"I'm obviously very pleased," Bircham told the club's official website.
"The last few months have been a bit up and down for me, but this is a huge pick-me-up.
"I've always stated I don't want to leave the club. I'm happy with my form but there is still a lot more to come from both myself and the rest of the lads."
"The buzz is back at QPR," added Bircham. "We have won two on the bounce since the gaffer has come in and the future suddenly seems a lot brighter.
"Success breeds confidence and the atmosphere in the squad is fantastic. We are determined to put our poor start to the season behind us and Saturday's result speaks volumes for the amazing impact John has made since he came in.
"The lads are all pulling in the right direction, we are all buzzing in training, and, as the last two results prove, especially on match days."