The trees in the wetlands of Tirunavaya are chock-a-block with nesting colonies of migrant birds that reach there from different parts of the country. The Asian openbill stork, the most predominant species found at Tirunavaya, has conquered most of the tree canopies in the midst of the wetlands in such a way as to drive away several other migrant species.
A study conducted among the Asian openbill at Tirunavaya shows that the population of the species doubled over a year, kicking out species like Black-headed ibis, Oriental darter, Black-crowned night heron, Little cormorant, and Purple heron.
The permanent wetlands in Pallar region of Tirunavaya spread over 25 hectares, where lotus cultivation takes places on a commercial basis, are a safe breeding ground for several local migrant birds. The availability of trees such as screwpine and Pride of India or Poomaruthu in the midst of the wetlands with little access for people has enticed the migrant birds to Pallar.
