Hybridization, the interbreeding of different species, is the object of much research and great interest (Mallet 2007, Abbott et al. 2013). As in many taxa (even humans; early modern humans hybridized with Neanderthals and Denisovans (Pääbo 2015)), hybridization is widespread in birds (Randler 2004, McCarthy 2006). According to the most updated literature mining, hybridization has been recorded in 2204 species from 30 bird orders in nature and/or in captivity (Ottenburghs et al. 2015). It presents various challenges to the definitions of species, studies of the process of speciation, reconstructions of phylogenies and strategies of conservation (Grant & Grant 1992). Birds and flowers are important components in traditional Chinese paintings. A masterpiece of Gongbi painting attributed to Emperor Huizong of the Song Dynasty, or Ji Zhao (reigned 1100–1125 AD), depicts a male pheasant resting on a hibiscus branch, his head turned to gaze at hovering butterflies (Fig. 1a). This pheasant shows chimeric characteristics from two species of pheasant (genus Chrysolophus), both of which occur in China (Lei et al. 2002): the Golden Pheasant Chrysolophus pictus (Fig. 1b) and Lady Amherst's Pheasant Chrysolophus amherstiae (Fig. 1c). The latter species has black and silver cape-like feathers on the sides of the neck and this pattern is clear in the painting. However, other characteristics of the pheasant in the painting are typical of the Golden Pheasant. The painting may represent artistic licence, or a nearly 900-year-old depiction of a hybrid bird. More than seven centuries after the painting was created, both the Golden Pheasant and Lady Amherst's Pheasant were exported to Europe. Hybridization between these birds was first described in 1872 (Elliot 1872). Subsequently, a natural male hybrid pheasant was captured in Sichuan, China, in 1964 and another was reported in 1974 (Deng 1974). This specimen closely matched the bird in the Song Dynasty painting. Additional reports of natural hybrids exist (He et al. 1993) and one hybrid bird also matches the painting (Fig. 1d). Thus, the earliest record of an avian hybrid can be traced back nearly 900 years. The hybrid pheasant in the ancient painting raises an interesting possibility. The massive number of centuries-old bird and flower paintings in various collections may serve to document the biodiversity of ancient China, even to the extent of revealing species lost forever. It is possible that more interesting findings will be made through collaborations between art collectors and connoisseurs and biologists in the future. We thank Xuan Guo, Li-Wei Li and Ming Zhang for providing the photographs of Chrysolophus pictus, Chrysolophus amherstiae and the hybrid, respectively. We also thank Dr Leslie Anthony for editorial feedback. This work was supported by the Chinese Academy of Sciences (CAS) ‘Light of West China’ programme. M.-S.P. thanks the Youth Innovation Promotion Association, CAS, for its support.
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