Short Communication: A pilot-study on the occurrence and probable factors influencing the population decline of House Sparrow (Passer domesticus) along an urbanization gradient in Coimbatore district, India

Abstract

Abstract. Narayanappa Y, Gautam A, Mahobiya K, Singh A. 2022. Short Communication: A pilot-study on the occurrence and probable factors influencing the population decline of House Sparrow (Passer domesticus) along an urbanization gradient in Coimbatore district, India. Biodiversitas 23: 3884-3889. The House sparrow is a widely distributed, human-commensal bird species across the globe. Over the past few decades, the population of this species has been reported to be declining at an alarming rate. The primary factor postulated to cause this decline is urbanization which leads to the unavailability of suitable nesting sites, a dearth of invertebrate food, the advent of phone towers, and electromagnetic radiation. The current study aims to document the occurrence, abundance and scrutinize the reasons for the decline of House Sparrows along a gradient of urban to rural in Coimbatore district, India. To estimate the abundance of House Sparrows, we counted them in16-points within a three 3km-radius along an urban-rural gradient. Information on gender, cluster size, detection distance, an angle from the observer, etc. were collected. The questionnaire survey was conducted to understand people's perceptions about the importance of the species and its current status. Along the gradient, we observed an average of 69.8 (±24.9) individuals. The species were abundant in rural and semi-urban areas, which is attributed to the availability of nesting sites, such as roof cavities, eaves, mud-walls, adequate feeding sources, presence of open scrub patches and garbage dumping sites adjacent to the residential spaces. However, sparrows were not present in the urban areas, even in their preferred habitats. According to the questionnaire survey, the likely causes for their absence are an increase in vehicle traffic, modern buildings, high-rise structures, and electromagnetic radiation from cell phone towers.