Baer's pochard females of Baer's pochard and the ferruginous duck are quite similar, but that holds true for the females of almost all "Aythya" species. Eclipse males resemble females, but retain the white eye. Formerly classified as a vulnerable species by the IUCN, recent research shows that its numbers are decreasing more and more rapidly. It was consequently uplisted to endangered status in 2008. In 2012, it was further uplisted to critically endangered. Between 1987 and 2007, there were only eleven reports of groups of 100+ birds in mainland China. A recent census by World Wildlife Fund (WWF) China of Hubei province
What is a Masterpiece? confluence of memories and emotions forming a single idea", that it has "a power of recreating traditional forms so that they become expressive of an artist's own epoch and yet keep a relationship to the past". The highest masterpieces are said to be "illustrations of great themes." Clark also implicitly excluded the erotic from considerations of what constituted a masterpiece, based on his perspective that a necessary condition is the balance between sense and form (works that are too sensual are, therefore, unbalanced and not to be categorised at masterpiece level). What is a Masterpiece? What is a Masterpiece? is