Most mobile developers prefer the Android OS over the Apple iOS for iPhones and iPads, despite Apple being first to market, says analyst Forrester.

Although the two OSes are pretty much tied in terms of popularity among developers in the US for phones and tablets, elsewhere, including Europe, Android is well ahead.

Forrester said: "Apple's first-to-market iPad tablet in 2010 allowed the company to build an early lead with mobile developers, but that margin appears to have vanished.

"For the second year in a row, we see more mobile developers in our survey targeting Android tablets than iPads, at 54 percent to 48 percent respectively."

But developer support for tablets varies significantly by region, Forrester said. Android and iOS tablet support is a dead heat in North America at 62 percent, while developer support for the iPad barely makes it past 40 percent in every other survey region.

Developer support of Android tablets is stronger than iOS in Europe, Asia Pacific, and especially in Brazil, where 59 percent of developers surveyed indicated support for Android tablets.

Forrester questioned over 500 mobile developers around the world about their chosen OSes and found that in some markets, like Brazil, the Windows Phone OS was making some headway, helping it it to take third place overall in the world market.

Interestingly, the new Mozilla Firefox OS was well ahead of the likes of the BlackBerry Phone and BlackBerry 10 systems, despite the fact there were currently barely any devices using the Firefox OS. Firefox was also ahead of the likes of the Tizen and Samsung Bada OSes.

Few carriers were so far showing much interest in the Firefox OS said Forrester, although a large number of developers in the likes of India were giving the OS a good position in the overall market, helped by Firefox's backers to develop a $25 smartphone for the lower end of the market.

Forrester said developers should not treat the mobile space as a two-horse race between Android and iOS though, and prepare for the emergence of new or emerging OS', particularly if they are active in multiple countries.