Share's in Zynga have been hit by the firm's declining userbase on Facebook, with the number of daily average users (DAUs) playing its titles down almost 5 million in little over a month.

That's according to Cowen & Co.'s Doug Creutz, who claims a 10 percent drop in Zynga's share price is due to firm's inability to hold onto Facebook users increasingly drawn to mobile platforms.

Fading Facebook force?

Creutz suggests Zynga currently boasts 54.2 milion DAUs across Facebook, but that's down 4.8 million from the firm's total back on 1 May.

The biggest loser was Hidden Chronicles, which lost 1.8 million players to finish on 3.3 million DAUs. Creutz notes, however, that the launch of Bubble Safarai has so far proved successful, jumping to the #3 spot and acquiring 5.7 million DAUs.

"We believe that mobile devices may be siphoning off an accelerating number of gamers from Facebook," added Creutz.

"Facebook itself is increasingly being accessed by mobile devices, however it is not possible to play Facebook-native apps through Facebook on a smartphone.

"We believe that over the last two months, trends in the casual digital gaming space have swung decisively towards mobile and away from social, at least in Western markets."

[source: Barron's]