Two short stanzas, and a surprising amount happening in them. The first line describes someone splitting their labor between a nest and a lily. That could be a bird dividing its attention between home and food, or it could be the speaker imagining a creature in nature as a kind of worker with a schedule. Either way, the natural world is given the language of jobs and duties.
The second stanza turns that idea into a joke with a slight sting. The speaker fears a "head tax" on the new moon, as if even the moon were property that could be counted, charged, and collected on. A head tax is charged per person, so the phrase makes the moon feel almost like a citizen or a household.
The mood is wry and gently anxious. The speaker seems to feel that the pressures of money and obligation reach even into quiet, natural things. The poem is playful, but it hints at a worry that nothing stays free of being measured and billed.