For two consecutive years, population estimates of avifauna were carried out. Simultaneously hydrological analysis of surface water of Mangla wetland was also conducted. Bird census was carried out in the months of January and February for both years (2010 and 2011) when a large number of migratory birds visit the Mangla Wetland. The birds were counted by the Point Count Method from a fixed point and for a fixed time period in such a way that the Sun was always behind the observer. A total of 37,082 birds belonging to eight orders, 11 families, 28 genera and 37 species visited the wetland in 2010, whereas in 2011, 21,302 birds belonging to six orders, nine families, 20 genera, and 28 species. Twenty two bird species were observed to be common in both years. The most abundant species were the Black-headed gull and the great cormorant in both years. The density of population was higher in 2010 (139.93 / km²) than in 2011(80.38 / km²). The level of Co2+, Cu2+, Fe2+, Mg2+, Mn2+ and Zn2+ in the surface water were within the permissible limits. However, the levels of Cr2+, Pb2+ and Cd2+ were higher than safe limits. The concentration of these metals showed variation in different months of the year. An extensive monitoring of the lake and catchment area is suggested in order to address the threats posed by heavy metals.