info from 1906 advertising from The American Stationer, Volume 60 by Howard Lockwood, 1906 which states SINGING THROUGH THE YEAR. A NOVELTY CALENDAR, CONSISTING OF THE REPRESENTATION OF A BIRD CAGE WITH BIRDS INSIDE. THE CAGE IS SIX-SIDED, AND THE CALENDARS ARE UPON FOUR OF THE SIX SIDES. THE DECORATIONS AND COLORING MAKE THE CALENDAR EXTREMELY ATTRACTIVE. info from Vintagepopupbooks.com
