Endemic Birds Day Special
"An endemic species is one that evolved in and has remained restricted to a particular place" (Quammen 1996). Rasmussen and Anderton (2005) say endemism means "Species restricted in global distribution to region". Raxworthy and Nussbaum (1996) mention that "Patterns of endemism are the product of historical events associated with speciation (e.g. time, place, and type of speciation event), as well as the responses of species to variable or changing ecological conditions (e.g. climatic change, competition)".
Very few studies have been carried out on the endemic birds of India. The preliminary information on the endemic birds in the Indian subcontinent was published by Ripley (1961), followed by Ali and Ripley (1974). Later, Grimmett et al. (1998), Kazmirzack and van Parlo (2000) have mentioned about the endemic birds in the Indian subcontinent. In addition to this, detailed study of endemic avifauna of the Andaman and Nicobar Islands was carried out by Vijayan and Sankaran (2000). In 2002, Zoological Survey of India published a book "Endemic Birds of India", covering 50 endemic bird species from India (Dasgupta et al. 2002). In this document they classified endemic birds based on the eight biogeographic zones in India.
Recently, Rasmussen and Anderton (2005) have published a book "Birds of South Asia: The Ripley Guide". In this book, they have made 198 species level changes, which include many species split within the region, split within extra-limital species and relocation of the race. They have also given comprehensive details about the endemic birds. About 218 endemic birds (see Annexure – I) have been recorded from South Asia, and the status of three species is yet to be determined. Interestingly, in India many subspecies of the birds are upgraded to the species level. Because of this upgradation 18 endemic subspecies were elevated to the species level. In our special section we have recorded 79 endemic birds in India. This means India comprises almost 36% of the endemic birds of South Asia.
This section describes the endemic, and some near-endemic birds of India. Bird diversity tends to change with various environmental as well as spatio-temporal factors. The status of certain species could not be determined due to unavailability of authentic information. The Large-billed Reed Warbler Acrocephalus orinus is classic example. It was known to science only from one specimen collected from Himachal Pradesh in India. It was considered as an endemic because the bird had relatively round wings (Ali and Ripley 1974). However, recently it was found in Thailand (Round et al. 2006). Similarly, the recently described Bugun Liochichla Liocichla bugunorum (Athreya 2006) is not included in this section as no information is available on its distribution and status.
Criteria for the endemism
To determine the endemic bird status we have followed four criteria:
1. Presence of the species only within Indian limits.
2. Majority of the population of the bird should be within India
3. Island endemics - The birds which are restricted to the Andaman and Nicobar Islands are treated separately. Some of the islands from the Andaman group politically belong to Myanmar; however, biogeographically they are a part of the Andaman group of island; especially the Table Island and the Coco Island. So, the bird species found on these islands are treated as endemic to India.
4. Vagrant and dubious records - Few vagrant and dubious records of birds from neighbouring countries such as Pakistan and Nepal are treated as endemic to India as there are no authentic records of these birds from those countries. Along with this, we have also included some species which are almost extinct in these neighbouring countries, but present in India.
Endemic Bird Area (EBA)
An Endemic Bird Area is defined as an area which encompasses the overlapping breeding ranges of restricted range bird species, such that the complete ranges of two or more restricted species are entirely included within the boundary of the EBA. This does not neccessarily mean that the complete ranges of all of an EBA’s restricted-range species are entirely included within the boundary of that single EBA, as some species may be shared between EBA’s (Stattersfield et. al. 1998). For details on Endemic Bird Areas, please refer to (Stattersfield et. al. 1998).
There are twelve Endemic Bird Areas (seven EBA and five secondary areas) occur in India, such as Andaman Islands, Assam plains, Central Indian forests (secondary area), Eastern Andhra Pradesh (secondary area), Nicobar Islands, Southern Deccan plateau (secondary area), Western Ghats, Western Himalaya, etc.