Where Ships of Purple gently toss — Sailor Beetle

Where Ships of Purple-gently toss-
On Seas of Daffodil-
Fantastic Sailors-mingle-
And then-the Wharf is still!
(F.296/J.265)
[1] Purple:: purple heron, a large bird with long legs and neck. toss:: to stir, disturb insects.
[2] Seas:: a great amount; ships, seas, and sailors are used to mislead our reading.
[3] Sailors:: sailor beetles, named after their bluish color (OED 3b). Fantastic:: quaint, fabulous of the blue beetles.
[4] Wharf:: the bank of a river. still:: quiet; herons fly away after feeding.

Sailor Beetles: "Certain red and blue beetles are known familiarly in Hants as Soldiers and Sailors." ─ Transactions of the Philological Society (1859)

"Purple Heron. General plumage reddish ash, inclining to purple: middle toe, claw included, as long as, or longer than the tarsus." ─ A Manual of British Vertebrate Animals (1835)