This is a vintage mid 20th century, dated 1957, limited edition en grisaille palette signed and numbered print featuring 6 Adelie penguins by the artist Roger Tory Peterson (1908-1996). Peterson was not only an artist but a teacher, naturalist and ornithologist. He is known for publishing the first modern field guide, 'Guide to the Birds' in 1938. This print was printed in an edition of 950 copies. It is triple signed on the front: in plate, meaning the signature is part of the print, by hand in pencil with the limited edition numbers and also by hand in fountain pen. There is an additional signature on the backside too. The estimate is based on actual recent past recorded auction sales of comparables. Retail 'asking prices' can be higher and vary.