Like the robotic Olympia who sang yesterday's Offenbach aria, Olivier Messiaen was very interested in birds. A lifelong amateur ornithologist, Messiaen had imitated the sound of birds in his early works. In his forties, however, the composer embarked on several large-scale projects based upon actual transcriptions of bird songs. The fourth of seven volumes, "The Reed Warbler," in actuality, contains the Warbler along with several other birds, as well as the sounds of their surrounding environment, in a half-hour-long movement representing an entire day from sunrise to sunset. Messiaen's desire to depict nature, along with his religiosity, often put him somewhat at odds with the musical avant-garde. A devout Roman Catholic, Messiaen was still very interested in the religious experiences of other cultures, particularly those of Japan and India.