Eco. Env. & Cons. 27 (1) : 2021; pp. (323-331) Copyright@ EM International ISSN 0971–765X Winter avifaunal assemblage in a periurban agricultural landscape of Gangetic West Bengal, India Pratyush Ghosh1*, Akash Chakraborty1 and Shouvanik Sengupta1, 2 1 Department of Zoology, Chandernagore College, Chandannagar, Hooghly 712 136, W.B., India 2 Department of Zoology, Asutosh College, 92 S.P. Mukherjee Road, Kolkata 700 026, W.B., India (Received 6 June, 2020; accepted 19 July, 2020) ABSTRACT The present study was carried out in a periurban agricultural landscape located at Boshipota, Hooghly, West Bengal, India with the objectives like preparation of inventory, evaluation of species composition, abundance and diversity and assessment of foraging guild of the avian assemblage during winter (November- February). Line transect method was employed for the avian survey. In total, 91 bird species belonging to 16 orders and 43 families were recorded over two consecutive winter seasons, i.e. 2018-19 and 2019-20. Passeriformes (50.5%) was the dominant avian order and Accipitridae (RDi=6.59) was found to be the most diversified avian family. Bird assemblage of the studied area has shown considerably higher species diversity as reflected in calculated values of different indices of diversity. Twenty (20) winter visitors were recorded from the study area. Analysis of foraging guild has revealed that most of the recorded species were insectivores (35 species) and least number of species is nectarivore (01 species). During the survey, only one ‘Near Threatened’ (NT) species was sighted and rest of the sighted species belonged to ‘Least Concerned’(LC) category (according to their IUCN status). This area has been found to have immense potential to attract avifauna but at the same time also becoming threatened due to rapid urban expansion and anthropogenic interventions. Key words: Bird, Diversity, Winter, Guild, Agricultural landscape Introduction Sekercioglu, 2006; Whelan et al., 2008). Characteris- tic avian assemblage of a particular landscape can Agricultural landscapes are progressively being rec- predict the ecosystem integrity and functioning ognized as refugia and often as primary habitat for (Hossain and Aditya, 2016). Functional diversity is a great array of species (Sundar, 2011). Birds usually a stronger determinant of ecosystem functioning tend to colonize in an area having suitable resources than taxonomic diversity (Gamfeldt et al., 2008). In for their survival (Veech et al., 2011). Agricultural addition to spatial distribution, the distribution of landscape, by providing concentrated and highly birds can also vary temporally (Mulwa et al., 2013). predictable source of foods to birds, attract a greater During winter, winter visitors agglomerate in differ- number of bird species, especially the migratory ent habitats including agricultural landscapes. On bird species (Dhindsa and Saini, 1994; Mariappan et the other side, increased fertilizer and pesticide in- al., 2013). Consequently, birds constitute a key com- put and more efficient harvesting methods could ponent of any agro-ecosystem and provide various have deleterious effects on avian assemblage of ecological services therein, notably seed dispersal agroecosystems (Redhead et al., 2018). Apart from and pest control (Haslem and Benett, 2008; that, progressive urbanization causes the most dra- 324 Eco. Env. & Cons. 27 (1) : 2021 matic and long-lasting land transformation, de- pletes agricultural lands and impart profound im- pact on avifaunal community, causing a significant decline in bird species richness throughout the globe (Rajpar and Zakaria, 2015; Mariappan et al., 2013). Climate change coupled with urbanization aggravates the problem (Pragasan and Madesh, 2018). There is scanty documentation related to avian diversity and community structure along ur- ban-rural gradient or in suburban and periurban areas in India. It is pertinent to create inventories of avifauna in the periurban areas of Kolkata and other metropolitan areas of India. Boshipota is located in the vicinity of Kolkata metropolitan area and its adjacent areas are now experiencing rapid urban growth. Considering this, the present study was undertaken with objectives like- to assess the abun- dance, residential status and species composition of birds and to document the taxonomic as well as functional diversity of avian assemblage during winter in a periurban agricultural landscape located at Boshipota, West Bengal, India. Fig. 1. Map showing location of the Study area- Materials and Methods Boshipota, Hooghly, W.B, India ( Source: Google earth ) Study Area transects were spaced at least 250 m from each other This study was undertaken in a peri-urban agricul- (Bibby et al., 2000). Fortnightly, avifaunal surveys tural landscape located at Boshipota in Hooghly dis- along transects were carried out on foot in the early trict of West Bengal. Boshipota (~22°40’N and morning hours (5:30-9.00 a.m.) and in the evening 88°19’E) is flanked by Dankuni industrial complex (3.00-5:30 p.m.), when the activity of birds is high- and township and Uttarpara-Makhla township (Fig. est. Total eight visits were made per season. No 1). This area is located about 12 km away from cloudy or rainy conditions were detected during the Kolkata metropolis. Physiographically, it is situated days of this study, we walked slowly to complete in the Ganga-Saraswati Plains. The landscape con- 200 m transects in 20 minutes, observing all birds sists of vast stretches of marshy lowland with culti- sitting or flying. All birds detected within 30 m on vated agricultural fields and scattered fallow lands either side of the transect lines were recorded. At with busy vegetation, stray trees and herbs, some each sighting, birds were counted and photo- ditches are also there. During winter, dry grasses graphed (using Nikon D3400 and D5600) whenever covered most of the uncultivated areas. Human possible. To confirm the species identity and to im- settlements are there at the edges of this landscape. prove the accuracy of counting, two Olympus field A narrow road with roadside tree patches bifurcates binoculars (10x50) were used. On the basis of field the whole landscape. observations and photographs, birds were identi- Methods fied using standard field guides (Ali, 2002; Grimmett et al., 2011). Bird surveys were conducted for two consecutive Taxonomic information of each detected avian winter seasons (November, 2018 to February, 2019 species like scientific name, order and family names and November, 2019 to February, 2020) adopting were compiled following Clements Checklists of the line transect method (Bibby et al., 2000). Ten 200 Birds of the World v2019 (https://www.birds. m long transect routes were selected randomly and cornell.edu/clementschecklist) (Clements et al., to avoid the counting of the same bird species twice, 2019) GHOSH ET AL 325 Each species recorded was assigned to one of the recorded from the study area. The species pool in- six feeding guilds, i.e. Carnivore (Car), Frugivore cluded 71 resident bird species and 20 winter visi- (Fru), Granivore (Gra), Insectivore (Ins), Nectarivore tors. During 2018-19 winter, a total count of 2931 (Nec) and Omnivore (Omn), according to their pre- individuals of birds from 16 orders, 42 families and dominant diet (Lim and Sodhi, 2004; Sigel et al., 85 species were recorded. Where as in the next win- 2010). Dietary information was collected mainly fol- ter seasons (2019-20), out of 2806 observations, 84 lowing (Ali, 2002 and http://www.hbw.com/) and species representing 16 orders and 41 families were also from field observations. recorded. A checklist of avifauna sighted from the Based on personal field observations and infor- Study area during 2018-19 and 2019-20 winter sea- mation from suitable documents (Khan and Naher, sons is presented in Table 2. 2009; Grimmett et al., 2011) birds recorded during Among the recorded species (91), 50.5% were one survey were classified under Resident (R) and passerines and 49.5% were non-passerines. Domi- Winter Visitor (WV). Some of the resident birds may nant Order Passeriformes alone represented 46 spe- also be local migrants. IUCN status of the birds is cies belonging to 22 families. Among the non-passe- collected from (https://www.iucnredlist.org). rines, Order Charadriiformes, Order Coraciiformes, Order Piciformes and Order Accipitriformes had Data analysis shown maximum species richness. All of them were Transect wise bird count data were pooled together represented by 6 species. While the least species rich for season. Based on this pooled data, relative abun- Orders were Apodiformes, Bucerotiformes, dance of the bird species was determined by using Caprimulgiformes, Ciconiiformes, Gruiformes and the following expression: Strigiformes - each was represented by only one n species (Fig. 2). Relative abundance (%) = × 100 N Among the winter visitors, 14 species (70%) be- longed to the Order Passeriformes, 3 species (15%) Where n is the total number of birds of a particular were under the Order Charadriiformes, 2 species species and N is the total no. of birds species. (10%) were from the Order Accipitriformes and the Relative diversity (RDi) of different avian fami- lies was calculated following La Torre-Cuadros et al. (2007). Shannon - Wiener index or Shannon index of di- versity (H’), Simpson’s dominance index (D), Simpson (1-D) and Pielou’s evenness index (J’) (Magurran, 2004) were calculated to discern the pat- terns of diversity of avifaunal assemblage using Past software version 3.20 (Hammer et al., 2001). Results Fig. 2. Percentage of species composition under different avian Orders During the Study period, overall a total of 91 bird species belonging to 16 orders and 43 families were Table 1. Classification of avian feeding guilds (Gray et al., 2007; Lim and Sodhi, 2004) Feeding guild Code used Food source Carnivore Càr Non insect animals including Vertebrates (e.g. fish, lizards), snails, large arthropods etc. Frugivore Fru Fruits Granivore Gra Seeds, grains and nuts Insectivore Ins Insects and some small arthropods Omnivore Omn Any two or more of the above Nectarivore Nec Floral nectar 326 Table 2.