Preparing pigeon message May 1917

Fixing message to the bird previous to leaving the trench. May, 1917.  

Credit: Canada. Dept. of National Defence/Library and Archives Canada/
Restrictions on use: Nil
Copyright: Expired 
Copy negative PA-001275
Item no. (creator) O-1415
Box (21)
Other accession no. 1964-114 NPC
Photographer: Castle, W.I. (William Ivor)
MIKAN no. 3381018