Migrating And Overwintering Ecology Of Black Stork (Ciconia Nigar) In Shidu Nature Reserve, Beijing

Black stork (Ciconia nigra) belongs to the genus Ciconia, the family Ciconiidae, the order Ciconiformes and the class Aves. Studies carried out so far were focused mainly on breeding ecology, population structure, behavior features, and so on, and were centralized at provinces such as Xinjiang and Shanxi. Little was known on its ecology in Beijing. In the present study, the populations, feeding habits, behavior and habitat characters of black stork in Shidu Nature Reserve were obersed and analized, hoping to offer basic methods and data for more in-depth research and fill the gap of researches on this bird species in Beijing. The main results are showed as following:1 The number of black stork population changed with a "low-high-low" pattern between September 2008 and February 2009. It was found that the feeding activities and habitat of black stork were seriously influenced because September and October are tourist season in Shidu Nature Reserve, that is to say that the black stork had to feed at the morning and the evening in order to avoid disturbance from the tourists. The number of the black stork increased in November, because the black stork gathered for migrating to the south. The population became the lowest at the end of November. In December, the number increased again, because some black stork migrated from the nourth for overwintering here, and some stoped here to feed themselves for further migration to the south. The black stork began to emigrate and the number declined again from February, because the water level of Juma River became lower and lower and the food available for black stork became less and less at this season. 2 By watching the foraging behaviour of black stork and investigating of samples in foraging area, it was showed that fishes were main foods of the bird, and some molluscs like gastropod could be subsidiary food. Black stork has two foraging behaviors:one is standing to watch and pecking it suddenly, and the other is walking and seeking with vigilance for a while.3 The daily activies and behavior characteristics of black stork were also observed. The behaviors included foraging, standing, moving, preening and resting, and so on. Foraging and resting were the main behaviors of black stork, which took, among all the activities, the longest time within a day. Furthermore, the behaviors differed in different phase. Forating was the major activity both in the mornig and the evening, and resting and preening were in the major one at noon. The difference was also affected by changes in foods and weather.4 The habitat of black stork was evaluated by habitat selection index. Accoding to the environmental characteristics of the Shidu Nature Reserve, the habitat of black stork was classified into 5 types, namely, bushes, marsh, fishpond, river and lake. It showed that the black stork preferred bushes and marsh for resting, avoiding fishpond, river and lake. Factors such as plant, warning, human disturbance, terrain, water source, and soil showed correlation to the habitat selection index for foraging of black stork. The open areas, less human disturbance, higher herbaceous vegetation with high water quality were suitable to black stork.