The food impact on the wintering Black-headed Gull(Larus ridibundus) in the region of Lake Dianchi,Southwest China,became a serious issue.In order to find their food selection,18 Black-headed Gulls were fed with 2-6 kinds of food during the 4 experimental stages in 2 large cages for 28 days and returned to the wildness.The results indicated that ① the Black-headed Gull preferred to feed on fresh loach,small fish and shrimp,but also took dry fish,bread,special food and cabbage;② the food consumption,62.67±30.10 g/d averagely and changing from 14.4 g/d to 118.6 g/d,increased when more kinds of food supplied but influenced by the foraging behavior and food edibility;③ the colony forage behavior was usually induced by few individuals,resulting in the increase of some kinds or total food consumption;④ the Black-headed Gull fed less food for 1 or 2 days before regularly forage when food composition changed,which was weaken if they suffered from 24 hour hunger;⑤ the body weight of caged Black-headed Gull decreased while that of wild ones increased during the experiment period, which implied that food supply was only one of factors influencing body weight growth.The authors argued that the wintering Black-headed Gull in the region of Lake Dianchi was forced to take a large amount of bread and special food provided by human beings to meet the lack of animal food in wildness.