THE BIRDS OF SIKKIM: AN ANALYSIS OF ELEVATIONAL DISTRIBUTION, ENDEMISM AND THREATS

ABSTRACT 2 ikkim, a small state (geographical area 7096 km ) located in the northeast part of India, is a paradise for ornithologists. Many explorers and scientists including famous ornithologist Salim Ali visited Sikkim for study S purpose. Most of the publications are based on taxonomy and systematics except a few recent ecological studies. We generated a database of birds of Sikkim based on literature and field studies during 2003-2006 with special reference to elevational distribution, endemism and threat. The state was divided into six zones based on vegetation types and altitudes. Generated database of birds of Sikkim shows a total of 574 species belonging to 253 genera and 55 families under 16 avian orders. Along the elevation gradient, species richness followed unimodal pattern with maximum species at mid-elevation zone. The number of habitat specialist (species occurring in single elevation zone) are more in the lowest and highest zones. A high turnover of species was observed along the elevation gradient with a few species showing wider distribution range. Ten eastern Himalayan endemic species are reported to occur in Sikkim. Of the total species, 17 are threatened (1 Endangered, 3 Critically Endangered and 13 Vulnerable) and 10 near threatened bird species. It is suggested that further study on birds of Sikkim should focus on ecology and habitat requirements of individual species especially of rare, threatened and endemics

Regional variation in the composition and structure of mixed-species bird flocks in the Western Ghats and Sri Lanka

Mixed-species bird flocks are attractive models for the investigation of geographical variation in animal communities, as they represent a subset of the avifauna in most forested regions of the world. Yet studies of the regional variation in flock size and the composition of flocks are few, due to the predominance of studies carried out at single study site. Here, we review nine studies of mixed-species flocks conducted at 16 sites along the Western Ghats in India and in Sri Lanka. We find that flock size varies as much within this region as it does globally, with observation time being a confounding variable. Flock composition, however, is predictably related to elevation. Flocks at high elevations (>1200 m) in the Western Ghats strongly resemble flocks at high elevations in the mountain ranges of Sri Lanka in their composition, especially at the family level. We compare these flocks to flocks of other regions and make recommendations on study methodology that can facilitate comparisons across studies

Elevational Gradients in Bird Diversity in the Eastern Himalaya: An Evaluation of Distribution Patterns and Their Underlying Mechanisms

BACKGROUND: Understanding diversity patterns and the mechanisms underlying those patterns along elevational gradients is critically important for conservation efforts in montane ecosystems, especially those that are biodiversity hotspots. Despite recent advances, consensus on the underlying causes, or even the relative influence of a suite of factors on elevational diversity patterns has remained elusive. METHODS AND PRINCIPAL FINDINGS: We examined patterns of species richness, density and range size distribution of birds, and the suite of biotic and abiotic factors (primary productivity, habitat variables, climatic factors and geometric constraints) that governs diversity along a 4500-m elevational gradient in the Eastern Himalayan region, a biodiversity hotspot within the world's tallest mountains. We used point count methods for sampling birds and quadrats for estimating vegetation at 22 sites along the elevational gradient. We found that species richness increased to approximately 2000 m, then declined. We found no evidence that geometric constraints influenced this pattern, whereas actual evapotranspiration (a surrogate for primary productivity) and various habitat variables (plant species richness, shrub density and basal area of trees) accounted for most of the variation in bird species richness. We also observed that ranges of most bird species were narrow along the elevation gradient. We find little evidence to support Rapoport's rule for the birds of Sikkim region of the Himalaya. CONCLUSIONS AND SIGNIFICANCE: This study in the Eastern Himalaya indicates that species richness of birds is highest at intermediate elevations along one of the most extensive elevational gradients ever examined. Additionally, primary productivity and factors associated with habitat accounted for most of the variation in avian species richness. The diversity peak at intermediate elevations and the narrow elevational ranges of most species suggest important conservation implications: not only should mid-elevation areas be conserved, but the entire gradient requires equal conservation attention

Breeding biology of the Malabar woodshrike Tephrodornis virgatus sylvicola Jerdon at Thekkady, Kerala

Volume: 89Start Page: 125End Page: 12

Foraging and nesting behaviour of Asian paradise-flycatcher Terpsiphone paradisi in Mudumalai wildlife sanctuary, Tamil Nadu, India

Volume: 19Start Page: 142End Page: 14

Nest, eggs and nest sites of the Andaman Crake Rallina canningi

Volume: 29Start Page: 158End Page: 16

Indigenous knowledge of Lepcha community for monitoring and conservation of birds

65-69The non-professional volunteers are commonly used in biodiversity assessment due to lack of experts. The bird identification skills of indigenous Lepcha community have been recognized and the accuracy of data generated by them has been assesed. Bird sampling was done using point count method along the transects in three locations in Dzongu, North Sikkim. Two observers, a trained ‘researcher’ and a local Lepcha folk referred as citizen scientist independently sampled birds (species by former and varieties by the latter). The mean number of species and varieties per point was not significantly different from each other. Gross accuracy of data collected by citizen scientist was high. These results showed that indigenous taxonomic knowledge of Lepcha community can be applied for biodiversity assessment programme provided the individual biasness of lumping and splitting is taken care

Regional variation in the composition and structure of mixed-species bird flocks in the Western Ghats and Sri Lanka

Mixed-species bird flocks are attractive models for the investigation of geographical variation in animal communities, as they represent a subset of the avifauna in most forested regions of the world. Yet studies of the regional variation in flock size and the composition of flocks are few, due to the predominance of studies carried out at single study site. Here, we review nine studies of mixed-species flocks conducted at 16 sites along the Western Ghats in India and in Sri Lanka. We find that flock size varies as much within this region as it does globally, with observation time being a confounding variable. Flock composition, however, is predictably related to elevation. Flocks at high elevations (>1200 m) in the Western Ghats strongly resemble flocks at high elevations in the mountain ranges of Sri Lanka in their composition, especially at the family level. We compare these flocks to flocks of other regions and make recommendations on study methodology that can facilitate comparisons across studies