LONDON — The chief Angry Bird is leaving the nest.

Rovio, the Finnish gaming company behind the popular Angry Birds franchise, said on Friday that its chief executive, Mikael Hed, would step down by the end of the year as the company struggles financially.

Rovio has struggled recently after quickly rising to prominence in 2009 when Angry Birds became a global phenomenon. The company has failed to respond to more recent trends in gaming, and the announcement highlighted once again the precarious situation of many mobile gaming companies, whose fortunes often rely on a single franchise or technology.

Gaming companies are often dependent on a sole blockbuster franchise like Clash of Clans, a game produced by the Finnish company Supercell. Others, including Zynga, also have faced difficulties in reducing their reliance on social networks like Facebook, which were instrumental in promoting the games when they were first introduced.

But people’s online habits change quickly — and franchises like Angry Birds can lose their popularity as quickly as they gained it. Analysts question whether Rovio and its rivals have the staying power to meet people’s fast-changing interests. And creating a second big hit has often proved elusive.