"Feathers of Vellayani", a publication of the Kerala State Biodiversity Board, says that the largest threat to Indian avian diversity was habitat destruction.
"The loss of forests, plains and other natural systems to agriculture, mines, urban development, draining of swamps and other wetlands reduce potential habitat for many species," says the 180-page book.
"Unfair alteration in habitat due to introduction and invasion of exotic species is also proving a threat to birds. Another is path-barriers that claim millions of migratory birds every year.
"Poaching, predation, weather and other natural and anthropogenic barriers prove devastating for birds... Bird populations are threatened as never before," the book says.
The well-produced book, costing Rs.250, is a rich collection of colour photographs of numerous birds, mainly those which populate the Vellayani Lake and adjoining wetlands in Thiruvananthapuram district.
Vellayani Kayal, as the lake is known in Malayalam, is a vast picturesque rain-fed lake surrounded by lush greenery and situated to the southeast of the Kerala capital.
The birds in the lake include Lesser Whistling Duck, Blue Rock Pigeon, Asian Koel, Indian Cuckoo, White Breasted Waterhen, Great Cormorant, Painted Stork, Indian Pond Heron, Cattle Egret, Pacific Golden Plover, Common Sandpiper, Greater Spotted Eagle, Brahminy Kite, Barn Owl, Small Bee-eater, Lesser Pied Kingfisher, Amur Falcon and Rose-ringed Parakeet.
Kerala is home to some 500 species of birds, 24 of them coming under the various threatened categories, the book says.
India itself has 1,168 bird species and has been ranked the ninth in the global list of bird wealth.
According to the book, the existence of such a large number of species of birds at Vellayani "will surely come as a surprise to many of the inhabitants of Thiruvananthapuram".
The book lists the birds seen in the area after observations over a period of over one year.
The topography of Vellayani is such that it is always water logged. The vast expanse of wetlands bordering the lake includes marsh, ponds, swamps and fields.
Experts estimate that more than 125 species of birds, including migratory ones, frequent the Vellayani lake and adjoining wetlands.
The book's authors are Oommen V. Oommen, an eminent zoologist and conservationist, K.P. Laladhas, an expert in the field, and Linda John, a bird watcher.
All three are attached to the Kerala State Biodiversity Board. (IANS)