| Bar-headed Goose (Anser indicus) is a species endemic to Asia, which mainly distributes in plateau wetland and was not fully documented. Since 2005, the species had been involved in a number of HPAI outbreaks and resulted in mass death, which draw widely concern on its biology, ecology and the role in spread of avian influenza virus. From 2006 to 2009, studies on breeding movement and migration of Bar-headed Goose were conducted at Qinghai Lake, a former HPAI epidemic area, and spatial-temporal relationship between migration of waterbirds at Qinghai Lake and HPAI outbreaks was analyzed. The main results are as follows:1. Community structure and spatial-temporal variation of waterbirds at Qinghai Lake after HPAI outbreakTotally 74 waterbird species was recorded at 17 sites of Qinghai Lake from Apr. to Sep., 2006 and Jan., 2007, which included 12 species of new record and 28 species susceptible to H5N1. The waterbirds mainly comprised of shorebirds and Anatidaes, in which 61.9% were passage migrants. The hot sites for waterbird were not changed after the HPAI outbreak in 2005, and the breeding population of Bar-headed Goose and Brown-headed Gull (Larus brunnicephalus) maintained stable, with more than half population of the latter one changed its breeding sites. The population of Great Cormorant (Phalacrocorax carbo) and Great Black-headed Gull (Larus ichthyactus), however, decreased by 28.2% and 18.9%. The diversity, species and abundance differed significantly among survey sites and months. Desertification, livestock grazing disturbance, residential and highway had significant impact on waterbird distribution.2. Breeding movement of Bar-headed Goose at Qinghai LakeIn nesting (NP, late Mar. to Apr.), incubating (IP, May to mid Jun.), raising (RP, late Jun. to early Aug.) and early migration (EMP, mid Aug. to early Sep.) period, the encounter rate of Bar-headed Goose was highest at estuarine (49.2±35.7%) and lowest at lake (3.8±14.7%). Radio tracking showed that the home range and core area from Apr. to Sep. covered 122.38±107.54km2 and 15.20±8.00km2 by 95% kernel estimator, respectively. The home range size and core area size increased as IP, EMP and RP, without significant difference. The movement distance averaged 4.70±6.87km and maximized 29.16km, which increased as RP, IP and EMP with no significant difference. Satellite tracking revealed most geese had different moulting site and pre-fall migration fueling site, with the average distance of 44.2±44.5km (11.2-140.2km). The molting date ended at 29 Aug. (17 Aug. to 19 Sep.). Livestock grazing and tourism were the major reasons resulting in contact between Bar-headed Goose and human. The contact intensity differed significantly at spatial and temporal scale, maximizing at Heimahe, Quanwan and Dandao, and in May, Apr. and Aug., respectively.3. Migration of Bar-headed Goose at Qinghai LakeTotally 8 Geese were successfully satellite tracked, among which 7 migrated southwestern along Qinghai-Tibet-India flyway and 1 southeastern along Qinghai-Yunnan-Guizhou flyway. Bar-headed Goose initiated fall migration from 21 Aug. to 7 Oct. (averaged 13 Sep.), at an average temperature of 4.8±3.4℃. Sudden drop of temperature had significant impact on the onset of fall migration. The Geese arrived at wintering ground on 21 Nov. (12 Nov. to 4 Dec.), leaved from wintering ground on 22 Mar., and arrived at Qinghai lake on 26 Mar.During fall migration, Bar-headed Goose covered 1378.3±186.4km over 72.0±17.6d, with an average migration speed of 19.5±2.0km/d. The goose made an average of 3.7±0.6 stopovers, with the successive traveling distance of 293.8±239.8km and maximaized 897.2km, travel speed of 136.0±102.4km/d and maximized 376.0km/d. During spring migration, the goose completed the migration over 4.3d with the migration speed of 268.1km/d, which significantly faster than that of fall migration.During fall migration, important stopovers included Zhaling and Eling Lake, Donggeicuona Lake, Yellow River in Maduo, Muli, Dangqu, Yellow River in Maqu, Yamdrok Lake, Yarlung zangbo River, et al, and wintering ground included Lhasa River, Yarlung zangbo River in Tibet, China, and Kohima of India, with wintering home range of 122.22±124.94 km2 by 100%MCP and 120.29±151.84 km2 by 95%Kernel estimator. Totally 44657 Bar-headed geese were recorded in wintering ground of Yarlung zangbo River in January, 2009, which greatly exceeds 10081 Bar-headed geese surveyed in the same area in 1990s. Therefore, we estimated a current world population of at least 70000, comparing to 52000-60000 documented by the Wetlands International in 2002. The wintering flock size averaged 208±262, with 72.1% of the total observations recorded in winter idle cropland.4. Spatial-temporal relationship between HPAI outbreaks in Central Asia-India Flyway and migration of waterbirds at Qinghai LakeA significant spatial correlation was found between HPAI outbreaks in Central Asia-India Flyway and migration of waterbirds at Qinghai Lake. In the temporal aspect, however, an asynchrony was observed in the majority part of year. The number of HPAI outbreaks maximized in wintering season and minimized in fall migration season of waterbirds. More HPAI outbreaks observed than that of expected in wintering and spring migration season, as opposite in breeding and fall migration season. Logistic regression showed that HPAI outbreak negatively correlated with latitude, and positively correlated with poultry density. There was also a higher HPAI outbreak risk in waterbird migration corridor. Therefore, understanding waterbird migration pattern, conducting whole year surveillance, highlighting dense poultry area and cutting off contact between poultry were essential in HPAI prevention and control.During Jul. to Aug. of 2007, we obtained cloacal and tracheal swabs and blood samples of 23 waterbirds representing 4 species, and collected 587 droppings at Qinghai Lake. RT-PCR revealed that 23 birds and all dropping samples were negative for avian influenza virus. However, the ELISA test for AIV antibody showed one Bar-headed Goose and Brown-headed Gull positive. These results revealed no birds were actively affected by AIV, but 8.7% were prior exposure to AIV and got immunity.
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