I posted that without remembering that the poem goes on, through 5 tercets also in iambic tetrameter. (I apologise for wrongly introducing the word 'quatrameter' in the last post; I was distracted by thinking about quatrains.) The rhyme is now AAA per stanza. These 5 stanzas are the THRENOS, or *Threne* or threnody indicated at the end of the previous part. The different stanza size clearly marks this section off. The section is basically a funereal announcement of the death of the birds, and of the qualities 'Beautie, Truth, and Raritie'. It's not made clear why these abstract qualities should be finished along with the birds.
― the pinefox, Thursday, 22 April 2021 15:11 (three years ago) link