"Birds" was the embryonic "Chuncho!" (Forest Creatures).  Because of the extraordinary popularity of "Birds" with audiences in 1951 and 1952, a gradual expansion of the piece took place and around 1953, "Chuncho!" sprang into being.  By the time Inca Taqui was recorded, the expansion had been completed.

Blues and jazz effects are more prominant in "Birds" than in "Chuncho!"  This is program music of an unsettling nature.  There is no melody to speak of but rather a sequence of loosely connected phrases.

Superbly sung, Yma provides myriad sounds, many of which were new to record groves at the time: whispers, 1/4 tones, growls, emphatic register breaks, birdcalls, insect sounds, as well as sudden changes in vocal placement, and variations of resonance and vibrato.  Listeners of the day must have been amazed at such sounds coming from their record players.  Although short, the piece is extremely well-judged and builds to a fine climax.  For this Yma chromatically rises to a pure, flute-like, F above high C and then descends with a glistening glissando to the contralto region.  (Later, when "Chuncho!" was recorded, this would be discarded for more outrè singing.)  The piece ends with Yma providing lip-flutters and whispers.