Bird diversity in historical paintings of the Song dynasty (960–1279)

Exploring past biodiversity is a fundamental step in understanding biodiversity change. However, ecologists are often impeded by a lack of evidence documenting past biodiversity (Guidetti & Micheli, 2011). Many ecologists have relied on tangible materials such as pollen, fossils, and specimens to identify species present in the past (Lister, 2011; Odgaard, 1999). In recent years, historic paintings are increasingly used in scientific studies, including tracking the evolution of shapes and colors in plant-based food (Vergauwen & Smet, 2020), capturing elements of air pollution (Albright & Huybers, 2023), and recording biodiversity (Davis et al., 2025; Tribot et al., 2021). For example, prehistorical paintings depicted endemic megafauna such as dwarf bovids (Bubalus sp.), and some of these paintings can be dated back to 43.9 thousand years ago (Aubert et al., 2019). However, most of these studies focus only on one or a few species, lacking a comprehensive understanding of biodiversity during that time. Bird-and-flower paintings from the Song dynasty in China (960–1279) contain species identifiable to the species level, providing an opportunity to explore bird diversity nearly 1000 years ago (Chen, 2024). Following the aesthetic ideas of Confucianism that strive to pursue knowledge through the investigation of things, artists of the Song dynasty created detailed and realistic depictions by observing wild species (Tucker & Berthrong, 1998). The realistic style of bird-and-flower paintings fully reached its peak during the Song dynasty with an astonishingly high degree of natural accuracy, especially when it was promoted by Emperor Huizong of the Song dynasty (reigned 1100–1126 AD), who was particularly strict with painters in the realistic style. One notable example of realistic Song paintings is the vivid depiction of predation by the Eurasian Goshawk (Astur gentilis) on the Common Pheasant (Phasianus colchicus) (Figure 1A). To investigate bird diversity depicted in 174 bird-and-flower paintings from the Song dynasty, we sourced examples from the book “The complete collection of Song dynasty paintings” (Song Painting Compilation Committee, 2008). We explored the diversity of bird species in these paintings and asked what types of bird species are more likely to be depicted. We found that historical paintings from the Song dynasty recorded a high diversity of bird species, which are predominantly common species. Among the 174 bird-and-flower paintings from the Song dynasty that we assessed, 90.8% featured bird figures that can be identified to species level (n = 158; Appendix S1: Section S1 and Table S1). There are 16 paintings depicting birds that could not be identified to species level, mainly geese and ducks. These species are not colorful, and artists preferred to depict them in a freehand style with ink and brush pen, rather than in a realistic style, to express emotions and feelings (e.g., inner peace and love). Therefore, these species cannot be identified to species level. From the remaining paintings, we identified bird figures to the species level based on their morphological traits, such as body size and color, as well as foraging attributes, social behavior, and habitats. As a result, a total of 67 species from 30 families were depicted (Appendix S1: Table S2). The Eurasian Tree Sparrow (Passer montanus) appeared most frequently in historic paintings (17 paintings), followed by the Eurasian Magpie (Pica pica; 13 paintings), the Mandarin Duck (Aix galericulata; 12 paintings), and the Chinese Starling (Acridotheres cristatellus; 10 paintings). Eighteen species were represented in more than five paintings, and 14 of these 18 species were among the currently most commonly encountered bird species in China (Appendix S1: Table S2). Our results align with discoveries of prehistorical art documenting past biodiversity. For example, commonly encountered species in southeast Asia, such as wild pigs and dwarf bovids, were painted in the earliest hunting scene in caves of Sulawesi (Aubert et al., 2019). Similarly, ancient cave paintings in Western Europe, dating back to at least 15,000 years, portray two now-extinct megafauna species like woolly mammoths and rhinoceros that were common during that era (Gross, 2020). Ancient artists preferred local and commonly encountered species because they were more likely to be observed and received more attention from early artists in their respective regions (Robinson, 2019). Species depicted in Song paintings were mainly distributed in eastern China, the main territory of the Song dynasty (Appendix S1: Figure S1). Henan and Zhejiang were the capital provinces of Northern Song and Southern Song, and our results showed that nearly half of the top 50 most commonly encountered bird species in Henan (23 species) and Zhejiang (24 species) were depicted in these paintings (Appendix S1: Section S2). As the most frequently depicted species in Song paintings, the Eurasian Tree Sparrow is frequently encountered by humans because of its large range size and population size, as well as its close associations with human habitations. In addition, many of these depicted species had associations with humans. According to the IUCN Red List, 58 out of 67 bird species depicted can use artificial habitats such as farmlands (IUCN, 2022), and early artists often depicted species vividly by using captive birds (Chen, 2024). In fact, 59 of these species are potentially traded as pets. For example, the Eurasian Tree Sparrow (Figure 1B) and the White Wagtail (Motacilla alba) (Figure 1C) were illustrated while tied with thin threads for observation. We also found that artists preferred rare bird species with cultural symbolism. In traditional Chinese culture, the Mandarin Duck, the Common Quail (Coturnix japonica), the Red-crowned Crane (Grus japonensis) and the Amur Paradise Flycatcher (Terpsiphone incei) are species representing love, peace, loyalty, and longevity, respectively (Appendix S1: Table S3). Although they are not all common species, they were frequently depicted. In addition, colorful species such as the Golden Pheasant (Chrysolophus pictus) and the Green Peafowl (Pavo muticus), even if rare, are depicted twice. Indeed, the cultural significance of species contributed to their popularity in artworks. Many bird species painted serve as “mascots” symbolizing auspicious meanings or scholarly virtues. For example, the Mandarin Duck represents peace, prosperity, and loyalty, making it a valued motif in Chinese textiles and interior furnishings (Zapolska, 2020). Similarly, the Eurasian Magpie (Figure 1D), symbolizing joy and good fortune (Chen, 2024), is also frequently depicted in bird-and-flower paintings. Our finding is consistent with a study on birds of North America, where species of high cultural value exhibited higher human interest (Schuetz & Johnston, 2019). Importantly, birds depicted in historic paintings provide valuable information on biodiversity change over time. Six species depicted in these ancient paintings are threatened now (Appendix S1: Table S2). Specifically, some of the formerly abundant and widely distributed species depicted in these paintings, such as the Yellow-breasted Bunting (Emberiza aureola) and the Blue-crowned Laughingthrush (Pterorhinus courtoisi) (Kamp et al., 2015; Li et al., 2021), are now critically endangered. The Yellow-breasted Bunting used to be one of the most abundant songbirds, with hundreds of millions of individuals during the 1980s (Kamp et al., 2015), and this species was depicted in Song dynasty paintings (Figure 1E). However, its population has become greatly reduced by 84.3%–94.7% between 1980 and 2013 due to illegal trapping, leading to its current classification as a critically endangered species by the IUCN Red List (Kamp et al., 2015). Similarly, the Blue-crowned Laughingthrush, another critically endangered species with fewer than 250 individuals in the wild today (Li et al., 2021), was also depicted in paintings (Figure 1F), implying that it was once encountered frequently during the Song dynasty. The Green Peafowl, once widespread and common throughout Southeast Asia at the start of the 20th century, is now classified as endangered due to habitat loss and excessive hunting (Brickle, 2002). Therefore, although our study includes a small number of bird species from the Song dynasty, these paintings provide information indicating that some endangered species in modern times were once abundant and widely distributed, and can increase our conservation awareness to reverse these declines. Interestingly, Song dynasty paintings also served as natural history records, for example, providing the earliest known depiction of an avian hybrid between the Golden Pheasant and the Lady Amherst's Pheasant (Chrysolophus amherstiae), which can be traced back nearly 900 years ago (Peng et al., 2016). Finally, the use of data from ancient artworks should be approached with caution due to the preferences of ancient artists. For example, a study showed that paintings by Turner and Monet captured changes in the optical environment associated with increased air pollution (Albright & Huybers, 2023), yet the conclusion was argued because the pattern probably only represents a change in painting style over time, not changes in pollution (Marmor, 2023). Therefore, biodiversity recorded in historical art paintings should be identified carefully and the information interpreted properly. Jiajia Liu conceived of the idea for the paper. Shuihua Chen identified the species in the paintings. Qianyu Chen conducted data collection and performed data analyses. All authors contributed to the final manuscript. We thank all contributors to the book “The collection of Song dynasty paintings,” and Sichuan Museum for granting permission to use photograph of Calyx Canthus and Dual Birds. We also thank Tiantian Zhang and Jiawei Li for visualization suggestions. This work was supported by the National Key Research and Development Program of China (2022YFF0802400). The authors declare no conflicts of interest. Appendix S1. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.