To mark the event philatelically a commemorative envelope was issued by the Royal Geographical Society of Australia (Queensland branch). Specially printed flimsies were also prepared for attaching to the legs of a flock of homing pigeons which made a special flight for the occasion.

The birds were released at 2.30 p.m. as the cairn was unveiled and the majority of the birds made it safely back to Mackay (on the mainland) at 3.30 p.m., although 13 birds fell victim to hawks.

Surviving records do not state how many pigeons or flimsies were involved. On arrival in Mackay the flimsies were collected and placed in the commemorative envelopes and were then mailed from Prosperpine, the nearest post office to Day Dream Island.

The flimsies were 2.25 cm x 6.25 cm printed in black on white paper with the following message:

QUEENSLAND'S FIRST PIGEONGRAM
Greetings of Goodwill
from
Day Dream Island
Barrier Reef.
9th June 1946
Carried by Homing Pigeon to the mainland on the occasion of the unveiling of a Cairn and Plaque, commemorating the 176th Anniversary of the Discovery and naming of Whitsunday Passage by Captain James Cook RN.

Each flimsie had a tag for sealing after the item was wrapped around the leg of the pigeon