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The Western Himalayas harbor high floral and faunal diversity due to diverse biogeographical influences and steep altitudinal gradients that nurture numerous forest types. Quercus leucotrichophora (banj oak) forests (1,500 m to 2,200 m.a.s.l.) form part of the moist, temperate, broadleaf forest biome located in the middle elevations of the Western Himalayas. Based on our research in Q. leucotrichophora forests from 2013 to 2019, we describe their avifauna with reference to taxonomic and functional diversity, seasonality, habitat specialization, and endemism. We then describe our recent findings on the influence of anthropogenic disturbances on oak forest birds in this human-dominated landscape. Over six years of observation we have recorded as many as 135 species of birds in this forest habitat, including year-round residents, summer migrants (breeders), winter migrants and passage migrants. An overwhelming proportion of forest birds (78.5%) are insectivores – both obligate and facultative. The abundance and diversity of insects and other invertebrates can be attributed to the complex branching pattern of oak, the lush canopy of oak forest, the moist duff layer and general plant diversity of these forests. Between 37% and 44% of the bird species recorded in oak forest are hardwood forest specialists in this elevational range and between 51% and 63% are forest generalists. There are a total of 17 Himalayan endemics and 4 narrow endemics that occur only in the Central-Western Himalayas. Bird abundance and diversity are adversely affected by Q. leucotrichophora forest degradation; insectivores and forest specialists were found to be most vulnerable. Reduction in canopy cover, landscape proportion of forest, vertical stratification and under story shrub density, as a result of forest degradation, most strongly affect forest birds. It is necessary to implement sustainable extraction measures and maintain old, protected oak stands if this diverse avifaunal assemblage is to be conserved. [ABSTRACT FROM AUTHOR]

• Quercus leucotrichophora dominated forest cover decline in Western Himalaya. • Simultaneous expansion of Pinus roxburghii forests in the study area. • Degraded oak stands transitioned to pine forest between 1991 and 2017. • Degraded oak-pine forest transitions more likely in drier, exposed sites with lower winter precipitation and more pine forest in the neighborhing landscape. Oak species worldwide are experiencing declines, with negative consequences for hardwood forests and their associated biodiversity, but the causes of these declines vary across species and habitats. We examine changes in extent of banj oak-dominated (Quercus leucotrichophora) moist temperate hardwood forests in a Western Himalayan landscape between 1991 and 2017. Using classified satellite imagery from 1991, 2001 and 2017, we found that dense banj oak forests have undergone substantial degradation and loss of area, while chir pine (Pinus roxburghii) forests have expanded, largely by replacing degraded banj oak stands. This transition was most likely to occur at sites that had lower levels of winter precipitation and Topographic Wetness Index (TWI) values and more pine forest in the surrounding landscape. Our findings are consistent with known requirements of shade and moisture for the recruitment of banj oak. Loss of banj oak forests is likely to reduce biodiversity and a number of ecosystem services linked to the well-being of local communities. [ABSTRACT FROM AUTHOR]