Abstract: The weight, length and other four indexes of 131 artificially fed blackheaded seagulls that were captured on Haigeng Dam of the Dianchi Lake in January of 2011 were measured, and the data were respectively compared to those measured from the specimen collected from different parts of Yunnan Province during the 1960s and 1980s. The results showed that there were no significant differences in the adult bird′s weight and tail length between the naturally and artificially fed birds (P>005), but there were extremely significant differences in the total length, wing length, instep length and the bill length of the two groups (P<001). The total length and the bill length of the artificially fed blackheaded seagull were extremely shorter than those of the naturally fed birds (P<001). Whereas the wing length and the instep length of the artificially fed blackheaded seagull were extremely longer than those of the naturally fed birds. There were no significant differences in the weight, wing length and the instep length of the subadult birds of the two groups. However, the total length, tail length and the bill length of the artificially fed subadult seagulls were significantly shorter than those measured from the naturally fed ones.