Tract morphological characteristics of four passerine birds were observed.Specimens were live-trapped with net in Qiqihar City,Heilongjiang Province during May and June,2004.All specimens were kept laboratory with mean temperature was 21℃(15-29℃)under natural photoperiod before the examination was conducted.Food and water were supplied ad lib.Sex of each specimen was recorded and body weight was taken.The entire digestive tract of each bird was removed carefully and separated from the connective tissues and lipids.The lengths of stomach,small intestine and rectum were scaled to the nearest 1 mm and the weights of each part of a tract were measured to the nearest 0.1 mg.In order to remove the effect of body mass,analysis of covariance was used to analyze the data,using body mass as the covariate,and followed by least significant difference multiple comparisons.The results showed that the total length,total empty weight and total dry weight of alimentary,stomach empty weight and stomach dry weight,small intestine length,small intestine empty weight and small intestine dry weight,and rectum length,rectum empty weight and rectum dry weight among these species had significant different.The granivorous,Carpodacus erythrinus,had the longest length of digestive tract(the length of stomach excluded).The tracts of the other three omnivorous/insectivorous species(Emberiza rutila,Luscinia calliope and Ficedula parva)varied.The insectivorous species(L.calliope and F.parva)had relative heavy digestive tracts among the four species.The results show that the different features of gut morphology among these species are a functional adaptation of the different food habits.