Rising temperatures mean that a large number of birds are no longer spending their winters in Shanghai. Last winter the average temperature in Shanghai was 8.1 degrees Celsius, the highest since record-keeping began in 1873. And according to ornithologist Yuan Xiao, that rise in temperature is the reason why the number of ducks and swans in Shanghai during the winter has dropped 90% in the past two years.
However, according to the Shanghai Daily, the number of bird species visiting Shanghai's wetlands has remained relatively stable over the past two years, and a Shanghai ornithologist's report stated that 117 species spent the winter in the wetlands, including 13 rare species.
Nations across the world regard Shanghai's wetlands as important habitats for water birds, and Chongming Dongtan is listed as a wetland of international importance in the Ramsar Convention on Wetlands, an international treaty for the conservation and sustainable utilization of wetlands. In order to be listed, a wetland must support 20,000 or more water birds on a regular basis and support 1 percent of the population of a single species or subspecies of a water bird.
But despite the number of birds at the wetlands, the ducks and swans have mostly disappeared, and likely won't return unless the temperatures dip again. The Shanghai Meterological Society says that the global warming is the cause behind the rising temperatures.
