Norfolk boobook morepork, being a small brown hawk owl with mottled plumage. It was smaller, darker and more reddish in colouring than the Australian subspecies, with much spotting. However, it was slightly larger than the nominate subspecies from New Zealand; female boobooks are larger than the males, with New Zealand females comparable in size to Norfolk Island males, a factor which gave rise to sexing difficulties with hybrid birds in the conservation management program. The owl inhabited the island's subtropical rainforest, which was largely cleared in the 19th century following human settlement. Most of the remaining forest lies within the small (4.65
Failure to refer Failure to refer Failure to refer, also reference failure or failure of reference, is the concept that names can fail to name a real object. According to Bertrand Russell's theory of truth, there is only one actual world, and a statement's truth value depends on whether the statement obtains in the actual world. Continuing the tradition of Gottlob Frege, Bertrand Russell posited that a name picks out, or refers to, a real object in the world (Russell's correspondence theory of truth). The name "Genghis Khan" thus picks out the 12th and 13th century Mongol leader we know by that name.