Comparison of Fluctuation of Species Number and Population of Breeding Species of Birds in Lake Urumia in 1981 and 2011

Main factor for Lake Urumia stability is the amount of water that causes survival of Fauna and Flora. Birds fauna is one of the most important indicators of expression of ecological condition of Lake  Urumia, and for this reason, in this research, changes of number of species and population of breeding birds in Lake Urumia in 1981(in wet year) and in 2011(dry year, the two third of lake was dry) were compared. In 1981 at wet year the average depth of lake Urumia was 6 meter and was normal, at that time 41 species of waterfowl, 112 species of terresterial birds, 40 species of Waders and Wading birds have been recognized in 1981, but in 2011 when the average depth of lake reduced to 4 meters, only 20 species of waterfowl, 62 species of land birds, 10 species of waders and wadding birds were found. In 1981 in wet year 12 species of waterbirds had bred in Lake Urumia, but in 2011, in dry year, this number reduced to only 2 species of waterbirds. Population of five species of breeding bird in 1981 was considerable.The breeding population of 5 species were as follow: Phoenicopterus ruber 100000, Pelecanus onocrotalus 3500, Tadorna tadorna 1000, Larus genei 5000 and Larus argentatus 8000 pairs, but in 2011 only 2 species had bred. The larus argentatus were 100 and Tadorna tadorna were less than100 pairs. By reducing the depth of water and drying the two third of lake in 2011 the colonial breeding bird's population were disturbed. Drying of the lake caused reduction in the habitat of the lake for water and terresterial birds.