Question

paragraph on endangered birds of Sikkim​

Answer 1

total of 573 species of birds occur in Sikkim (Acharya & Vijayanunpublished data) of which ten are endemic. Out of these endemic species, we observed only five species during this study.  A maximum of four endemic species were recorded in zone II and III followed by two species each in zone I and IV. While no endemic species was found in the alpine zone of Sikkim.

Among the five species recorded by us, Rusty-bellied Shortwing Brachypteryx hyperythra was rare with a density of 1.33/ha and 3.22/ha in zone III and IV respectively. The other four species (Broad-billed Warbler Tickellia hodgsoni, Hoary-throated Barwing Actinodura nipalensis, Yellow-vented Warbler Phylloscopus cantator and White-naped Yuhina Yuhina bakeri) were locally abundant and observed in two or three elevation zones.  The density of Broad-billed Warbler was highest in zone IV, Hoary-throated Barwingin zone 111

Discussion and Conclusions

 

Five endemic species, namely Chestnut-breasted Partridge Arborophila mandellii, Wedge-billed Wrenbabbler Sphenocichla humei,Rufous-throated Wrenbabbler Spelaeornis caudatus, Ward’s Trogon Harpactes wardii and Giant Babax Babax waddelli were not observed during the course of this study.  Among these species, Chestnut-breasted Partridge was reported to occur in habitats similar to zones I, II and III, Rufous-throated Wrenbabblerto zone IV and Wedge-billed Wrenbabbler to zone V (Ali 1962; Ali & Ripley 2001; Islam & Rahmani2004) but the distribution of the rest two is not known.

Similarly, out of the 17 threatened and ten near-threatened birds of Sikkim (IUCN 2009), only three near-threatened species (Rusty-bellied Shortwing,Firethroat and Satyr Tragopan) were observed in Sikkim during this study. Species such as Palla’s Fish Eagle Haliaeetus leucoryphus,Black-breasted Parrotbill Paradoxornis flavirostris, and Beautiful Nuthatch Sitta formosa are reported to have a wider distribution range but the other species such as White-rumped Vulture Gyps bengalensis, Long-billed Vulture Gyps indicus, Red-headed Vulture Sarcogyps calvus,Baer’s Pochard, Aytha baeri, Greater Spotted Eagle Aquila clanga, Lesser Kestrel Falco naumanni, Blyth’s Tragopan Tragopan blythii, Black-necked Crane Grus nigricolis, Slender-billed Babbler Turdoides longirostris, Rufous-necked Hornbill, Aceros nipalensis and Wood Snipe Gallinago nemoricola have merely presence-absence records in Sikkim (Ali 1962; Ganguli-Lachungpa 1998; Ali & Ripley 2001; Islam & Rahmani 2004).

The result indicates that the population of these birds in Sikkim is very low.  Habitat loss and fragmentation is considered the major factor for decline in population of threatened and endemic birds in the Himalaya and elsewhere (Crosby 1996; Mauro & Vercruysse2000; BirdLife International 2001; Chettri et al. 2001, 2005; Riley 2002; Robin & Sukumar 2002; Pandit et al. 2007).  It is reported that endemic birds are unable to utilize non-forest habitats resulting from deforestation and conversion of land to other uses (Lei et al. 2003; Wijesinghe& Brooke 2005; Vijayan & Gokula2006).  Fragmentation and loss of habitat of the restricted range species threatens their very survival (Lei et al. 2003). The study by Pandit et al. (2007) predicts that by the end of this century, a quarter of the endemic species of the Himalaya will be extinct due to habitat loss. Extinction of endemic species is primarily driven by the loss of potential breeding habitat (Mauro & Vercruysse 2000; BirdLife International 2001).

Maximum species of endemics and threatened birds in Sikkim are found in tropical broadleaved forests (zone II) and temperate broadleaved forests (zone III).  The diversity of birds is also high in these zones (Acharya 2008).  Tropical and temperate broadleaved forests are breeding ground for most of these species but human population pressures and various ongoing developmental projects have posed serious threats to these habitats.  The forests in zone II is outside the purview of current protected area network (Acharyaet al. 2008).  Hence, conservation through community participation would be effective for conservation of birds in these habitats.

This study was undertaken as a part of the bird community study in Sikkim which was more focused to understand the distribution pattern of birds along elevation gradient (Acharya 2008).  Hence, some species might have been missed or densities underestimated though special attention was given to endemics and threatened birds.  Long-term specific study on these species provides better understanding of population status, distribution and threat.  Hence, detailed study on the ecological aspects and habitat requirements is necessary for the execution of species-specific conservation measures.