The copyeditor frequently has to explain her spelling or style choices. In this case, it was prompted by the confusion between Canadian and US spelling.
The Royal Canadian Geographical Society’s choice of the grey jay, also called the whisky jack, as Canada’s new national bird has ruffled some feathers — and the correct spelling of the bird’s name has provoked confused and angry comments from CBC readers.
Source: CBC’s spelling of grey jay/whisky jack is not for the birds