He said that the number of birds in the sanctuary has decreased due to filling of wetlands and settlement within the sanctuary, severe spread of invasive species of Valletta in sanctuary and pollution of the water systems such as Bolgoda canal and Katu canal flowing across the sanctuary due to the disposal of chemicals by the near by factories.
This sanctuary is home to not only migrant birds but also native birds. In addition to birds such as Heen Gembithuruwa, Ambala Koka, Mal Seruwa, Wee Kukula and Palal Sera native birds such as Gira Maliththa and Dumburu Demalichcha cannot be found inside the sanctuary today.
It is said that the area around the sanctuary has been rapidly urbanized which has been identified as another reason for the reduction in number of birds.
A number of different types of fish in the waterways of the region are also reported to be at the risk of extinction.