The competition is heating up for mobile operating systems and manufacturers alike. Android had the mobile market on lockdown for the better part of 2011, but the iPhone 4S launch helped Apple make a surprise comeback towards the end of the year. According to US market watcher Nielsen, Q4 of 2011 saw Android’s share of the smartphone OS market drop from 61.6 percent to 46.9 percent. That’s still ahead of iOS, but Apple’s market share rose from 25.1 percent to 44.5 percent during this time frame. There’s no telling if Apple will be able to continue encroaching on Android’s share of the market, but the timely launch of the iPhone 4S proved to be a smart move.

Competition amongst Android handset makers

Apple’s intent on ruling the consumer market only fans the flames of competition amongst Android handset makers. Samsung’s been the dominant manufacturer in the Android camp, edging out HTC which saw losses last year. Sony Ericsson is having a tough time as well, reporting a 20 percent decrease year-on-year for handset sales. The company cites growing competition and price erosion as reasons for their slipping profit, with a net loss for Q4 amounting to $267 million. Sony Ericsson’s loss only emphasizes the woes Android handset makers face in relying on the open source operating system as their primary entrant into the mobile market.

Sony Ericsson’s hoping to turn things around with refreshed focus, thanks to Sony’s acquisition of the Ericsson branch. The deal, expected to be finalized in February at the latest, will centralize Sony’s efforts. “It allows us even deeper integration with Sony offering. Our focus on Android, our focus on smartphones will not be different,” CFO Bill Glaser told Reuters in an interview.

Instagram skipping Android for Windows Phone?

Android’s become a highly relevant OS on a global scale, but it’s not the only platform in town. Rumors of Instagram heading to Android have been on the rise these past few weeks, and Instagram CEO Kevin Systrom has even promised an Android app in the future. But the latest rumblings indicate that Instagram may hit Windows Phone first. The unconfirmed rumor says that the Windows Phone team’s been working with Instagram on creating an app, and should Instagram hit Microsoft’s devices next, plenty of Android fans could feel slightly miffed.