The global diversification of songbirds (Oscines) and the build-up of the Sino-Himalayan diversity hotspot

An adult Asian Open-billed Stork (Anastomus oscitans) was observed in the Longjing reservoir of Baise City, northwestern Guangxi Zhuang Autonomous Region on 3 October 2010. It is the first record of this big stork in Guangxi, southwestern China. The Longjing reservoir is located in the Youjiang district of Baise, with a total area of about 200 ha. This reservoir, surrounded by Masson pines (Pinus massoniana), is also a fishpond for local people. The reservoir was draining water to net fishes when we detected this stork. The stork foraged snails and fishes at the edge of the reservoir every noon. It also picked up dead fishes from the net. Sometimes it even bit at the dobbers of fishing nets. Many waterbirds, including the Little Egret (Egretta garzetta), the Chinese Pond-Heron (Ardeola bacchus) and the Grey-headed Lapwing (Vanellus cinereus) foraged for food with this stork. It was the most cautious among these waterbirds. It often stayed on high branches of Pinus massoniana trees. Only after other birds foraged for a long time, did it came down to the reservoir. This stork stayed in the Longjing reservoir for about three days and we never saw it after 6 October.

The Asian Open-billed Stork is a waterbird not difficult to identify, commonly appearing in southeastern Asia, in countries such as Bangladesh, Myanmar, Laos, Cambodia, Thailand, Vietnam and India (Zheng et al., 2002; Robson, 2005; BirdLife International, 2009). The first record of the Asia Open-billed Stork was prepared by a Chinese birdwatcher, Yitian Wang, in Xihu lake, Dali City, Yunnan Province in October 2006. Since its first occurrence in China, the Asian Open-billed Stork had not been recorded during the following four years. The stork has, since then, been recorded three times in southwestern China this year. Six Asia Open-billed Storks appeared in Jinggu County, southwestern Yunnan Province in July 2010 and two were observed in Anshun County, southwestern Guizhou Province in September 2010. Baise City is adjacent to China's Guizhou and Yunnan provinces and Vietnam. The distance from Baise City to Anshun County is about 300 km, as the stork flies. Although the Asian Open-billed Stork is a colonial breeder, resident in India, it usually leaves its breeding place every December (Pramanik et al., 2009). Is it an occasional event for the Asia Open-billed Stork to migrate in exceptional weather, or is southwestern China a potential overwintering area? The questions need more surveys of this bird to be answered.