Avian diversity in the paddy field ecosystem surrounding the Assam University campus in Silchar during the rainy season

Abstract

Rice (Oryza sativa L.) is one of the most effective crops for absorbing carbon dioxide. Paddy is a temporary reservoir for rainwater during the rainy season, prevents soil erosion, and emits oxygen through photosynthesis. In Assam, it occupies 88.89 percent of the net cropped area. Paddy field ecosystems are also home to various cultivated and wild species of plants and animals where numerous aquatic and bird species can be found. These fields provide waste rice, a crucial food source for various bird species. The quantity of waste rice positively correlates with rice yields, and birds often feed on freshly planted rice seeds. Paddy fields constitute a semi-aquatic ecosystem that is heavily infested by insect pests. These fields also attract waterfowls, wading birds, shorebirds, and other waterbirds for migratory movements and foraging. From this pilot study conducted in the paddy field ecosystem surrounding the Assam University campus in Silchar we report 95 species of birds that belong to 37 families and 14 orders. Highly sighted avifauna included Egret, Heron, Bittern (family Ardeidae), Waterhen (family Rallidae), Kingfisher (family Alcedinidae), Drongo (family Dicruridae), and Dove (family Columbidae). Interestingly, eight 'Least Concern' bird species according to the International Union for Conservation of Nature (IUCN) – Hooded Pitta (Pitta sordida – family Pittidae), Cinnamon Bittern (Ixobrychus cinnamomeus – family Ardeidae), Watercock (Gallicrex cinerea – family Rallidae), Common Sandpiper (Actitis hypoleucos – family Scolopacidae), Emerald Dove (Chalcophaps indica – family Columbidae), White-Browed Piculet (Sasia ochracea – family Picidae), Dark-Necked Tailorbird (Orthotomus atrogularis – family Muscicapidae) and Brown Fish-Owl (Ketupa zeylonensis – family Strigidae) as well as a ‘Vulnerable’ species Lesser Adjutant Stork (Leptoptilos javanicus – family Ciconiidae) and ‘Near Threatened’ species Alexandrine Parakeet (Psittacula eupatria – family Psittacidae) were also noted. Out of a total 95 avian species, 46 species belonged to the insectivorous category, accounting for the greatest number according to the feeding guild recorded within different line transects in Visual Encounter Surveys (VES) conducted weekly from March 2023 to August 2023. Although the avifaunal studies have enormous potential in the Barak Valley, conservation measures are essential to protect the biodiversity. Public involvement in awareness campaigns and conservation activities is crucial for conserving avian diversity within the Valley. As paddy fields are used primarily by grassland and wetland bird species, there are significant information gaps in the monitoring of bird populations in paddy cultivation as well as in different stages of rice growing cycles, which makes it essential to understand the importance of paddy fields on avian populations as well as diversity.