The author died in 1921, so this work is in the public domain in its country of origin and other countries and areas where the copyright term is the author's life plus 100 years or fewer.
{{Information |Description ={{en|1=A photograph of two model ducks, the right countershaded and camouflaged and the left just camouflaged.}} |Source =Thayer G.H 1908 The concealing colouration of animals: new light on an old subject. Century...
