Alexander Wetmore, Canaries: their care and management (1923)
“ The food requirements of canaries are simple. Canary seed to which have been added rape seed and a little hemp is a staple diet that persons who keep only a few birds usually purchase ready mixed. Canary seed alone does not furnish a balanced food, but forms a good combination with hemp and summer rape. Much of the rape seed in prepared seed sold in cartons is of a species that even wild birds do not eat, as it is pungent and bitter in flavor, but all relish the mild taste of true summer rape. Seed is given in little cups that are fastened between the wires of the cage. ”
