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Location India, Tamil Nadu
Central coordinates 78o 52.00' East  9o 22.00' North
IBA criteria A1, A4iii
Area 2,541 ha
Year of IBA assessment 2004

Bombay Natural History Society

Site description Big Tank or Peria Kanmai (System Tank) (891 ha) and Sakkarakottai Kanmai (Non-system Tank) (1,650 ha) are twin wetlands of great importance for bird conservation, although they were initially built to provide irrigation and drinking water. Peria Kanmai is fed by the River Vaigai and Sakkarakottai Kanmai is rainfed. These wetlands are located 5 km north of the district headquarters at Ramanathapuram. The wetlands are rich in aquatic flora, especially Scirpus, Cyperus pygmaeus, Cyperus difformis and Cynodon dactylon. Ipomea carnea can be seen in dense stands on the periphery.

Key Biodiversity 

AVIFAUNA: This site has been selected as an IBA based on the large numbers of congregatory waterfowl, and especially as a nesting site for the globally threatened Spot-billed Pelican Pelecanus philippensis. The wetlands have attracted waterfowl immediately after the completion of the dams. Many birds started nesting on the numerous Acacia nilotica trees found inside the tank. Significant numbers of heronry species such as the Grey Heron Ardea cinerea, Purple Heron Ardea purpurea, cormorants Phalacrocorax spp., Cattle Egret Bubulcus ibis, Little Egret Egretta garzetta and Large or Great Egret Casmerodius albus nest there. Coot Fulica atra is also found breeding on these wetlands. Recently small numbers (35-40) of Spotbilled Pelican were found breeding. Balachandran (pers. comm. 2003) has found that the pelicans shift their nesting site between these two wetlands, depending upon availability of water. The Big Tank (Peria Kanmai) is close to the Gulf of Mannar, from where Greater Flamingos Phoenicopterus ruber frequent this lake in thousands when the water level is low (S. Balachandran, per. comm. 2002). During the Annual Waterfowl Count in 2002, nearly 1,600 were sighted. A very large congregation of ducks is also seen. At a time, there may not be as much as 20,000 birds (A4iii criteria), but in a year more than 20,000 birds use these wetlands. These tanks also attract many species listed as Near Threatened. On 25 April, 2002, 1,800 White Ibis Threskiornis melanocephalus, 250 Black Ibis Pseudibis papillosa, 1,300 Glossy Ibis Plegadis falcinellus, 1,500 Painted Stork Mycteria leucocephala and 2000 Little Egret Egretta garzetta were seen, along with other waterbirds (S. Balachandran pers. comm. 2003). The numbers were much more than the 1% mentioned by Wetlands International (2002).

OTHER KEY FAUNA: As these wetlands are surrounded by human habitation, there is not much large terrestrial fauna.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Spot-billed Pelican Pelecanus philippensis resident  2004  present  A1  Near Threatened 
A4iii Species group - waterbirds unknown  2004  20,000 individuals  unknown  A4iii   

IBA Monitoring

2003 low not assessed not assessed
Good - based on reliable and complete / representative data

Biological resource use hunting & collecting terrestrial animals - intentional use (species being assessed is the target) happening now small area/few individuals (<10%) no or imperceptible deterioration low
Biological resource use logging & wood harvesting - unintentional effects: subsistence/small scale happening now small area/few individuals (<10%) slow but significant deterioration low
Pollution industrial & military effluents - type unknown/unrecorded happening now small area/few individuals (<10%) slow but significant deterioration low


IUCN habitat Habitat detail Extent (% of site)
Coastline   -
Artificial - aquatic   -

Land use

Land-use Extent (% of site)
agriculture -
Notes: Cultivation of vegetables on the banks
fisheries/aquaculture -
Notes: Fishing

Acknowledgements Key contributors: S. Balachandran, S. S. Ramchandran Raja and V. Kannan.


Wetlands International (2002) Waterbirds Population Estimates: Third Edition. Wetlands International Global Series No. 12. Wageningen, the Netherlands.

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Big Tank (Peria Kanmai) and Sakkarakotai Kanmai. Downloaded from on 26/10/2016

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