Indigo Bunting
There is something irrepressibly cheery about the song of an Indigo Bunting. The male’s paired notes ring out from a high perch, where this unbelievably blue bird positively sparkles in the sunlight. According to Cornell’s “All About Birds” site, the male sings as many as 200 songs per hour at dawn and for the rest of the day averages a song per minute. To hear an indigo bunting sing, go to http://www.allaboutbirds.org/guide/Indigo_Bunting/sounds .
Song Sparrows
The return of song sparrows and their energetic songs tells us spring has definitely arrived. The males sing a sequence of notes, including clear whistles and buzzy sounds. According to nature recordist Lang Elliott, each male has about ten songs in its repertoire and tends to repeat one pattern for several minutes before changing to another. Although other birds may produce more musical songs, you’d have to search far and wide for more enthusiastic outbursts than those of a song sparrow.
Naturally Curious with Mary Holland 
What Other Naturally Curious People Are Saying