What is the meaning of "Only lovebirds, not fairies"?

It means that we only envy the lovebirds who can grow old hand in hand and be together for life. The only way to do that is to be a god in the sky.

Ten Mile Pinghu Lake

The background song of The Secret Soul

Ten Mile Pinghu Lake is full of frost

Inch by inch, the silk is worried about the years of life

To the moon, single look at each other

Only envious of mandarin ducks, but not envious of the immortal

Added

There is no source of the poem, and it is a reference to the "Baiyi Qingxiang Poetry - Farewell to the thought of the" poem. If you want to say the author, it should be Ruan Jizhi, the scriptwriter or Tsui Hark, the producer of the movie "Sinister Souls", because this poem was first appeared in a painting in the movie "Sinister Souls" directed by Tsui Hark, and the original text should be as follows: "Frost fills the sky in the ten-mile flat lake, and the green threads of the silk are worried about the Chinese years. To the moon shape single look at each other to protect, only envious of mandarin ducks not envious of immortality", but before that, in 1959, Li Hanxiang director of the "Sinister Souls", there are: "Ten miles of flat lake green sky, jade hairpin secretly cherish the Chinese years. If the rain cover can protect each other, only envious of mandarin ducks, not envious of immortals", visible Xu version again changed from Li version.

Reference: read.net/cnread1/net/poems/b/baiyi/011.htm