The poem tells about the month May where all birds come home from winter and build a bridal bed. Only for the I-figure spring gives only tears.
This song is based on the fourth motive in the first song (m. 7-9). just transpose the fourth motive a third, and adjust it to the scale of song 5, and you have the main line of the start of the theme of song 5. Also the characteristic rhythm of this song is derived from the first half of m. 8 of the first song.
The rough structure of the song is again very simple: Intro-A-A-A-coda. The song is in C, but at the start of the song the suggestion is towards G as a tonic. The introduction of the seventh in the G chord in m. 4 is the first point where the real tonic is suggested. The introduction is full of bird songs. The first three measures, including the trill at the end, are a beautiful representation of bird song, as are the eight notes in the Adagio, and the trills in m. 7 and 8 combined with the eight notes. Also the right hand piano in m. 9 is obviously a bird, as is the melody in m. 12 (G-F-D-F).
The piano introduces the melody of the voice in m. 13. It is a very playful and fluid melody with only small steps, first going downwards from G to G and then rising and falling between A and D. The bass is very basic with only G and C. The 1/8-1/8-1/4 rhythm is very pronounced and only stops at the end of sentences. In the last beat of m. 18 the harmony becomes a minor. This is made explicit by the Gis in m. 19.
The piano interlude in m. 21 brings back the birds, where the harmony moves towards F major (E-a-F). Then the second half of the theme starts in F and transforms through the D7 and G back to C in m. 26. This excursion in harmony is consistent with the text, where the swallow comes back home and love will live in his nest. Recognize that the melody in the last part, on "die Liebe soll wohnen da drinnen", is build around triads instead of scales, making the melody more static, i.e. giving the feeling of being home. The line of the main beats in this part of the theme is D-E-F-E-D-C, giving also stability. The same is true for the use of the G7 chords to confirm the C major tonality. The upward movement in the bass gives also the feeling of coming home. Recognize also that the second "die Liebe..." is a variation on the first one.
The piano interlude shows again the birds, and then the whole theme is repeated exactly, even the piano accompaniment. The third repetition starts with a piano interlude that repeats the longer trill of the start of the piano prelude and varies the introduction of the song by using triplets in the right hand. But when the voice starts, the first half of the theme is again an exact repetition of the first theme.
At the moment the text tells that the happiness of spring is not for the I-figure, the piano changes. A ritardando gives more accent on the minor tonality, where in m. 56 a Gis is added to the chord to accentuate the a minor tonality. And the piano interlude has a melancholic melody instead of the bird song. When the voice starts with the second half of the them, the piano has a little bit fuller chords, and when the text is about tears the piano has full chords with silence in between. Also the motive E-Fis-G in m. 63 represents the bitterness of the situation. The adagio in the postlude is full of lamentation.