Of the 25 'threatened' species, three are listed as 'critically endangered', five as 'endangered', and 17 as 'vulnerable'. Eleven species are categorised as 'near threatened'.
A study by ZSI has revealed that there are as many as 78 bird species which are found only in India. There is a rich diversity of 10,906 bird species in the world, and of them, India is home to 1,353, Zoological Survey of India scientist Amitava Majumder said. These 1,353 bird species account for 12.4 per cent of the global avian diversity, he said.
According to the International Union for Conservation of Nature (IUCN) categorisation, 25 of the 78 bird species, which are found only in India, are classified as 'threatened', the scientist said.
"Seventy-eight bird species are found only in the country's geographical region. On the occasion of the 75th Independence year, we have focussed on 75 such species in the book, '75 Endemic Birds of India'," Majumder told PTI.
These selected winged species exhibit "remarkable distribution patterns" across various regions of the country, he said. Twenty-eight bird species are restricted to the Western Ghats, 25 to the Andaman and Nicobar Islands, four to the Eastern Himalayas and one each to the Southern Deccan plateau and Central Indian Forest, the scientist said.
Of the 25 'threatened' species, three are listed as 'critically endangered', five as 'endangered', and 17 as 'vulnerable'. Eleven species are categorised as 'near threatened'.
Majumder said three bird species - the Manipur Bush Quail (Perdicula manipurensis), listed as 'endangered' by IUCN, the Himalayan Quail (Ophrysia superciliosa), categorised as 'critically endangered', and the Jerdon's Courser (Rhinoptilus bitorquatus), classified as 'critically endangered', - have not been included in the ZSI publication.
According to records, the Manipur Bush Quail was last sighted in 1907, while the Himalayan Quail and the Jerdon's Courser were last seen in 1876 and 2009 respectively, he said.
Some researchers believe that the Mottled Wood Owl and the West Himalayan Bush Warbler are only available in India's geographical region but new records and distribution patterns indicate their existence in the nearby countries, Majumder said.
Malabar Grey Hornbill Ocyceros griseus, Malabar Parakeet from the Western Ghats and Nicobar Serpent Eagle Spilornis klossi, Andaman Barn Owl Tyto Deroepstorffi from the Andaman and Nicobar Islands among others have been featured in the ZSI publication.