Wintering ecology of the Black Stork (Ciconia nigra) in Beijing

The Black Stork (Ciconia nigra) is a new winter resident in Beijing due to temperature changes.To understand the wintering ecology of this species better, a field survey covering the number of birds of this population, habitat selection, feeding activity and grouping behavior was conducted at the Shidu Nature Reserve from January 2004 to March 2009. The results show that the Black Stork selected the Juma River at this nature reserve as their new winter habitat. The number of birds in this population decreased from 28 in the 2004/2005 winter to 17 in the 2007/2008 winter with a subsequent recovery to 23 the following year. The wintering flock was formed in mid-November and dispersed in mid-March, but the date changed with seasonal temperature fluctuations. The storks exhibited feeding habitat fidelity and the main food type was fish (＞ 92.4%). There was no significant variation in food composition between adults and sub-adults (Mann-Whitney U test, U = 1.00, p = 0.44). Feeding activity occurred in the morning and at noon during early winter, but concentrated in the afternoon during mid winter, divided into dawn and dusk in late winter. Daily fish intake was 538 g for adults and 449 g for sub-adults if the period of foraging reached six hours in the wild, which was similar to the level under artificial feeding. Agonistic behavior among feeding birds was observed among group members in late winter. The main negative factor for wintering Black Stork was a reduced feeding habitat resulting from increased water depth due to damming of the river to benefit tourism and to wetland exploitation.

Habitat utilization and resource partitioning of wintering Hooded Cranes and three goose species at Shengjin Lake

The loss and degradation of wetlands have adversely affected waterbirds, which depend on wetland habitats. Interspecific competition has an important effect on habitat utilization of wintering waterbirds. Resource utilization, including partitioning, in degraded wetlands has become a hot issue in ecological studies of wintering waterbirds. In order to have an insight into the habitat utilization and resource partitioning between a Hooded Crane(Grus monacha) population and the guild of three goose species, i.e., Anser fabalis, A. albifrons and A. erythropus wintering in lake wetlands, we carried out a study at Shengjin Lake National Nature Reserve from November 2011 to April 2012. We surveyed the Hooded Cranes and goose guild foraging in various habitats during the wintering periods with a combined method of fixed route searching and fixed site observations. Resource partitioning was studied by means of calculating habitat utilization rates and the width and overlap of spatial niches. The results showed that the habitat utilization rate and the width of spatial niches of the Hooded Crane population and goose guild shifted with the season. The habitat utilization rates of the cranes in grasslands were high at all three wintering stages. The habitat utilization rates were 0.454, 0.435 and 0.959 respectively for the Hooded Cranes and 0.627, 0.491 and 0.616 for the goose guild. This suggests that the overlap in grasslands was higher between cranes and goose guild. Most habitats were accessible at the middle stage, so the width of the spatial niche of the cranes(1.099) and goose guild(1.133) both reached their peak at this stage. The greatest niche overlap was 0.914 for these two groups at the late stage, followed by 0.906 at the middle stage and the smallest was 0.854 at the early stage. Ecological response to the changes in habitats of wintering waterbirds was clearly shown in the dynamic variations of the niche of both the Hooded Cranes and the three goose species. Coexistence among waterbirds was achieved by regulation of niche width to reduce niche overlap and relieve interspecific resource partitioning.

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 Black- necked Crane Nature Reserve.These areas are Nierixiong and Jiaqingze Villages in Nierixiong Xiang and the Shab Chu Valley.