Joseph-Philippe-François Deleuze, History and description of the Royal Museum of natural history… (1823)
“ A great number of birds, especially those remarkable for the beauty of their colours, have a totally different plumage according to their age, and even sometimes according to the season. Thus the same bird has often been described and drawn several times under different names. It is only after many researches that the different varieties and the passage from one to the other can be determined. We frequently see ten or twelve individuals of one species, presenting the same essential characters, but whose colours are totally different. ”
