Sparrows in urban complexity: macro and micro-scale habitat use of sympatric sparrows in Guwahati City, India

In recent decades the House Sparrow and Tree Sparrow have suffered considerable declines. To date, little is known about the fine scale habitat selection of sparrows where they occur together. We investigated how sympatric sparrows used macro and microhabitats in the urban environment of Guwahati city. Survey of sparrows was carried out in 572 locations of different urban settings to find out the city scale distribution. We classified urban habitats and collected micro-habitat variables at 45 point count stations during 2013–2015. Urbanization gradient was found to be influential in limiting the abundance of sparrows. House Sparrow was more common within the urbanized areas compared to low settlement densities located far from the urban core. In contrast, Tree Sparrows were more scattered and seldom found in crowded areas. Spatial overlap was comparatively high in the residential areas adjacent to hillocks. At micro scale, House Sparrow had quadratic response to the degree of urbanization. Both the species avoided areas where urbanization reached the peak; specifically, the areas which were completely devoid of natural vegetation and top soil was paved, and in shopping centers with glass facades. Habitat requirements of both the species at local landscape scale seemed to be similar, although, with some overlaps, they occupied different gradients of the urban environment. Since urban landscapes are highly managed, the fundamental tool for enhancing urban sparrow populations would be the protection of mosaic habitat prioritizing suitable design and management of private gardens and allotments.