From: Popular Backyard Birds Identification Ringtones Vol 1 »

This compilation of backyard bird sounds has a variety of familiar songs. With these high quality bird calls and songs as ringtones, callers to your cell phone can help you with bird call identification. Most of these tracks include several different sounds made by each bird so the longer your phone rings, the more you learn! Assign different bird calls or songs to different callers and put your iPhone to work as a bird call identification tool. 

Each identification ringtone is $2.99