Zhenniao (Chinese: 鴆鳥; pinyin: zhènniǎo) or sometimes translated as Zhen or Poisonfeather Birds, is a name given to poisonous birds that is said to have existed in what is now present-day Southern China during ancient times and is referenced in many Chinese myths, annals and poetry. The Shanhaijing Chapter 5: Classic of the Mountains: Central describes the Zhen as resembling an eagle living in Girl's Tabletop Mountain, Lutemute Mountain and Jade Mountain in Southern China.
Existence
Wild Zhenniao were supposedly last seen in the Song dynasty, when many farming Han Chinese moved to Guangdong and Guangxi. Humans are supposed to have killed them all. Chinese ornithologists have often theorized that the Zhen was similar to the secretary bird or the crested serpent eagle (which happens to live in Southern China) and gained their toxicity from ingesting poisonous snakes, similar to how the poison dart frogs produce poison by ingesting poisonous insects. As a consequence, in some illustrated books, pictures very similar to these two birds have been used to depict the Zhen.
However, throughout most modern history, zoologists knew of no poisonous birds and presumed the Zhen to be a fabulous invention of the mind. But in 1992, an article was published in Science reporting that the hooded pitohui of New Guinea has poisonous feathers, and since then a few other species of similarly poisonous birds have been discovered. A recent article in China has been published bringing up the question if the Zhen bird could have really existed.