Number and distribution of Black-necked Cranes wintering in Zhigatse Prefecture, Tibet

We surveyed all known wintering areas of the Black-necked Crane (Grus nigricollis) in Zhigatse Prefecture of the Tibet Autonomous Region during three winters. Our surveys confirm that Zhigatse Prefecture is the most important wintering area for the species, accounting in some years for as much as 39% of the estimated world population. Counts ranged from a high of 4240 cranes in January 2007 to a low of 2636 in February 2009. Chick recruitment (chicks/100 cranes) ranged from 8.2 (January 2010) to 11.3 (January 2007). The highest concentration of cranes during all three surveys occurred on the 60 km stretch of the Yarlung Tsangpo (River) between Lhaze and Phuntsoling. To evaluate potential impacts of the Xietongmen Copper Mine, we monitored wintering crane numbers prior to mine installation in an intensive study area located between the Shab Chu Valley and the city of Zhigatse. Our surveys recorded on average 820±83 cranes (SE; n=8) in this area. With the installation of the mine at a location~50 km west of Zhigatse, increased traffic and development on the north side of the Yarlung River will likely result in a shift in crane distribution away from the north side, to nearby suitable habitats. Based on our survey results, we recommend three areas hosting high numbers of cranes in the vicinity of the mine be added to the Yarlung Tsangpo Middle Reaches Blacknecked Crane Nature Reserve. These areas are Nierixiong and Jiaqingze Villages in Nierixiong Xiang and the Shab Chu Valley.