Lost ability to hear the bird calls!

I have a brand new iPhone 4s and I installed the California Birds app. The app worked like a charm and all of the sudden it stopped playing the bird calls/sounds. I checked the settings and the "on" for sounds is on.
Wondering if anybody else has encounter the same issue and/or can help me find a solution.

Thank you,

Santiago

I figure it out -I guess there is a price to pay for using a new device!!!
Chao for now,

S