| Saunders' Gull (Larus Saundersi) is a rare species of Laridae in the world,which is mostly breeding in the eastem coast of China, such as Liaoning,Hebei, Shandong, and Jiangsu. In l999,24 breeding colony has beendiscovered in the Siwha Lake, near Anshan, Jingiidao, Korea. Very fewbreeding ecological research on the specie has been done in China. FromMarch to July in l999 and 2000, we have carried out fleld survey work onSaunders' Gull in Yancheng National Nature Reserve of Jiangsu Province.Using Multi-variable Statistical analysis methods, we are carrying outfurther research on the reproductivity and breeding habitat selection ofSaunders' Gull.1 The major behaviors of Saunders' Gull are feeding and resting during theprevious breeding period. Everyday there are two high feeding period,which are during 8-l0 and l4-l6. It drinks distinctly in the moming, noonand evening. The adult takes more time to rest and warn, less time to feedand move than the young bird. The successful feeding frequency of theadult is higher than that of the young bird. It takes more time to wam, lesstime to feed and rest in the artificial wetland than the original wetland.2 In l999, the Clutch of Saunders' Gull had no significance distinctionbetween Aleuropus littoralis and Suaeda yhaura habitats, but there aresignificance distinction between the length and fresh weight. In l999,there is a significance distinction for the fresh weight of Saunders' Gull indifferent breeding orders, but no significance distinction for the length andwidth of Saunders' Gull. The length and width of Saunders' Gull had nosignificance distinction between l999and 2000, but the fresh weight hadsignificance distinction. Nest spatial structure of Saunders' Gull isfollowed by the negative binomial distfibution in the Core area ofYanbheng N'NR.3.The dUraion of breeding season for SaUnders' Gul in Yancheng NNR isl25 days in l999 and l l l days in 2000. The date of laying the first egg istheCtCd by climatC, Watr sources, hUman ativihes, food sources. The aretwo peaks in the nesting time of laying the first egg, but uns can notilluIninthe that SMers' Gull hatCh two times in one hatehing season.4.There are no distinct significance of nest success, hatching success,nestling success bbeen twO habitas. There is no diStinct significance ofnest success, and distinc sighficance of hatching success and nestlingsuccess betWeen l999 and 2000.5. There are no distinct significance of laying mortality and nestlingmortality and distinct significance of hatching mortaJity in l999.Hatchingmortality has the greatest effect on insrteous mortality in AleuroPusIittoralis and Suaeda yhaura habitas in l999.The stUdy in 2000 sti1lshows that hatching mohality has the greatest effect on instamaneousmortality There are no distinct significance of laying mortality andnestling mortality and distinct significance of hatching mortality in l999and 2000.6. Egg loss caused by preying has the greatest effect on the tOtal lose rateand hUman fetching also contribllted a 1ot to the total lose rate betWeentWO habitats in l999.Egg loss caused by preying still has the greatesteffect on the total lose rate, and egg loss caused by the climatC and humanactivities also have much effeCt on it in the study of twO years. There areno distinct significance of egg loss caused by the flood, preying, fetchingand egg abandoning and significance of the tOtal loss fate, egg loss causedby the climate, hUman activities and ndown reason in two years.6. By Path Analysis of different mortaity nests and nestlings, disotanceand Water source distance, it showed that laying mohality hatchingmortality and nestling mortality produced great imPacts on theinstananeous mortality and among them, hatching mortality had thegreatCst influence on it. Human activities have the greatest effect on layingmortality There are Strong correlation betWen laying mortality andhaching mo... |
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