Seosan A, B area is located on 36˚ 42̍ of north parallel and 126˚ 27̍ of east longitude. It consisted of broad artificial lakes and reclaimed agricultural lands; there is Ganwalho lake in A area and Bunamho lake in B area. Total birds surveyed four times in 2001 at the A area are 105,580 of 11 orders, 28 families, 89 species. Among them, resident species were 21 species including Pica pica. Twenty species including Cuculus canorus were summer migrants, and 30 species including Platalea leucorodia were winter migrants. Seventeen species including Limosa limosa were occasionally species. And Rostratula benghalensis was an unconfirmed species. Species diversity index (H') was 0.72; species equally common index (eH') was 2.06. In January, maximum observed 102,121 individuals. However in July 52 species were observed most variously. There were total 81,152 birds observed with 11 orders, 22 families, and 71 species at the B area. Fifteen species including Falco tinnumculus were resident species. Summer migrants were 18 species including Ixobrychus sinensis. Winter migrants were 25 species including Ciconia boyciana. Thirteen species including Tringa glareola were occasionally species. Species diversity index (H') was 0.281; species equally common index (eH') was 1.325. In January, maximum observed 78,433 individuals. However in July 42 species were observed most variously.