It's not just Apple's iPhone that's threatening the strength of the BlackBerry in North America, but the growing popularity of Android smartphones among consumers, analysts say.

North American consumers are still key for Research In Motion (TSX:RIM), even though the BlackBerry maker is expected to post continued international growth on Thursday when it releases its first-quarter results.

"There's more competition on the smartphone front in North America than there ever has been," said IDC senior analyst Kevin Restivo.

Restivo said RIM and Apple were still No. 1 and 2 in North America, but that gap is narrowing and the appeal of Android-powered smartphones is growing.

"Android and the devices that Google's partners are making have very quickly become hot commodities in the United States," Restivo said from Toronto.

HTC and Motorola are among handset makers helping to popularize Google's open-source Android operating system in their smartphones.

But, RIM has made the Asia-Pacific region and Latin America priorities as those regions are quickly adopting smartphones, said Restivo, of IDC's worldwide mobile phone tracker unit.

The average analyst estimate for RIM's earnings per share for the company's first quarter of 2011 is US$1.33 and revenues are expected to be US$4.3 billion, according to those surveyed by Thomson Reuters.

Technology analyst Nick Agostino said he expects that RIM has likely lost consumer market share in North America and that trend will eventually spill beyond its borders.

"Where Android and iPhone and RIM are really starting to butt heads is in North America and that's going to spread to a more international level," Agostino of Toronto's Mackie Research Capital.

He said the North American market is important because it's considered the home of smartphone adoption. Smartphones allow users to surf the Internet, watch video, listen to music and install applications that let them do everything from find restaurants to read books.

"The North American consumer tends to be more high end and, therefore, it gives you a sense of who is going to control the high end of the market."

But, Agostino said, he believes the Waterloo, Ont.,-based company will be able to maintain its share of the business market in Canada and the United States.

Scotia Capital analyst Gus Papageorgiou said in a note to clients he's looking for RIM to have revenues of US$4.4 billion and earnings of US$1.34 per share.

"The Street is clearly concerned about RIM's competitive position and future in the smartphone market, concerns we believe are almost entirely without merit," he wrote in a recent note.

RIM co-CEO Jim Balsillie has said RIM will continue its global expansion, but still has to compete in North America, a market he has described as "hotly contested.''

To appeal to more consumers, RIM is expected to introduce a touchscreen phone with a pullout keyboard. It is also rumoured to be working on a tablet device that would work with a BlackBerry.

Citi Group analyst Jim Suva said RIM will be challenged in both the consumer and business market, in which RIM is known for its secure delivery of email.

"While RIM’s growth has been fuelled by international and consumer growth, we see increasing challenges on these fronts as Android adoption continues at brisk pace," he wrote in a note.

Suva noted RIM's North American market share has declined to 41 per cent since the launch of Motorola's Android device, Droid, on U.S. carrier Verizon.

However, Restivo said, concerns about RIM's growth are largely unfounded.

"RIM's problem is that it's No. 1. Everyone looks to see the top dog falter in some way, shape or form."