A STUDY OF AVIAN DIVERSITY IN DURGAPUR GOVERNMENT COLLEGE CAMPUS, WEST BENGAL, INDIA

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INTRODUCTION
The study of the diversity and distribution patterns of organisms and their function in the ecosystem are important and challenging at the same time. Birds are one of the most important components of any ecosystem [1]. They have been recorded to function as scavengers, pollinators and predators on various organisms, which helps to maintain the balance of the ecosystem [2]. Avifauna exhibit diverse patterns in their habitat selection and studies focusing on their diversity and various habitat conditions are becoming ever more popular [3 -6]. Moreover, birds have been found to be correlated with an increase in satisfaction and happiness among the human population [7]. Unfortunately, in recent times various observations and studies made by researchers all around the globe have shown that bird populations are facing serious problems due to habitat destruction and climate change [8 -10]; accordingly, the frequency of out-of-range avifaunal records is increasing day by day [11,12].
Durgapur is a transitional zone between Chotanagpur Plateau and Gangetic Plains and therefore shows a wide range of diversity in its topography as well as in its faunal composition [13 -15]. However, despite its rich fauna, this region is considered as one of the least studied regions of West Bengal. Out of the 1451 species of birds found in the Indian subcontinent [16], which makes up about 13 % of the total birds found globally, according to studies conducted by Durgapur Wildlife Information and Nature Guide Society from 2013 to 2022, Durgapur has about 250 species of birds [17,Unpublished data]. Various works on the avifauna of Durgapur were conducted in the previous years [18 -22] and several works are still in progress. Being located in the middle of an area with rich diversity, the Durgapur Government College Campus also has a huge diversity of plants [23], insects [24], reptiles, amphibians, birds and mammals. However, much of its faunal composition has still remained a mystery to the outer world because of the lack of exploration and studies. Campus Bird Count, a global event organised to study the avifaunal diversity of college and university campuses around the world, provided a chance to explore the untouched corners of the campus and record various interesting observations. Therefore, the primary objective of this study was to prepare a checklist of bird species in Durgapur Government College Campus covering a range of seven consecutive years.

Study area
The present study was carried out in Durgapur Government College ( These trees and other plants provide shelter and food for birds and other animals, and in a way make the campus highly bio-diverse. The temperature of the study site ranges between 8 and 43 °C and the average rainfall varies between 6 and 213 mm.

Methodology
Birds were spotted and observed using 8X40 magnification binoculars and identified using suitable field guides [25,26]. The bird survey was done following the point count method for bird diversity study. Also, various opportunistic spotting was added to the list. The survey was conducted from January 2013 to January 2020 on a monthly basis during morning (05.30 AM -09.00 AM), afternoon (03.00 PM -04.00 PM) and evening (07.00 PM -08.30 PM). Birds that occupied the college campus were recorded separately from the birds flying over the campus area. The scientific names and the IUCN status of the birds given in the checklist are shown according to Birdlife International. The data collected was used to estimate the status and diversity of the avifaunal species.
Study of diversity indices is much essential for monitoring biodiversity and conservation. The diversity indices used in the present study were Shannon-Wiener species diversity index [H / ], Pielou's evenness index [J / ], Margalef's richness index [DMARG] and Simpson's dominance index [DSIMP]. All the diversity indices were calculated in PAST version 3.25 Software [27].

RESULTS AND DISCUSSION
A total of 106 bird species belonging to 47 families were recorded during this study in Durgapur Government College Campus (covering an area of about 12 hectares). Among these 106 bird species, 96 were found to be actively using the college campus as shelter and/or foraging area while the rest were recorded only as flying over the campus area. The detailed checklist of the birds along with their IUCN status, population trend, and migratory status is given in Table 1.
In a similar kind of study Aggarwal et al. [28] have reported exactly 106 bird species belonging to 52 families in the Indian Institute of Forest Management (IIFM) campus, Bhopal (covering an area of about 93 hectares) during their nine-month study. Again, Chandrakar and Dhuria [29] have reported 81 bird species belonging to 38 families during their year-long study in Guru Ghasidas University campus, Bilaspur, Chhattisgarh (covering an area of about 700 hectares). In another study, Singh et al. [30] have reported 45 bird species belonging to 23 families during their six months study in the campus of Deen Dayal Upadhyaya Gorakhpur University, Gorakhpur (covering an area of about 121 hectares). Higher bird diversity in the present study in a much smaller geographic area could be attributed to the longer study period (seven consecutive years), as well as the higher bird diversity of the studied location. Sylviidae was recorded as the most diverse bird family with 9 species, followed by Ardeidae and Motacillidae with 6 bird species. Birds from the Sylviidae family are well known for their restricted movements due to their adaptation to short-distance flight patterns. They are mostly forest-dwellers and the studied location having enough diversity of tree population supports higher diversity of bird species from Sylviidae family. This finding agrees well with Jha's research [31]. Other notable bird families were Columbidae and Cuculidae (each had 5 representative bird species) and Muscicapidae and Sturnidae (each had 4 representative bird species). Of the remaining 40 families, 8 were represented by 3 bird species, 13 were represented by 2 bird species and the rest 19 families were represented by a single bird species. A similar kind of finding was made by Mahato et al. [32] in and around Purulia town, West Bengal. Out of the total 106 bird species, 23 were winter visitors, 4 were summer visitors, 1 was passage migrant, 1 was vagrant and the rest 77 birds were residents ( Figure 2). and Common Kestrel were seen flying over the campus area most of the time.
Variation in bird species number during different months in the study period is presented in Figure 3. Winter months actually showed higher bird diversity due to the presence of winter migrants like pipits, warblers, flycatchers, wagtails and shrikes along with the residents. This was also confirmed by the study of diversity indices (Table 2) where the Shannon Weiner general diversity score was found to be highest for the month of November (3.102), followed by January (3.027). Similar patterns were also observed for Margalef's richness index where the highest scores were observed during the months of November and December (7.822 and 7.691 respectively). These findings agree well with the previous studies made by other researchers [32,33].
In this study, the highest bird density was recorded in the month of March (Figure 4). This was the time of the year when winter migrants started leaving the study area and the resulting species richness was the lowest. . The global population trend of the recorded bird species in this study is given in Figure 5. A total of 106 different bird species belonging to 47 families were recorded. Sylviidae was recorded as the most diverse family. Out of the 106 bird species, 23 were winter migrants, 4 were summer migrants, 1 was passage migrant, 1 was vagrant and the rest 77 were residents. Winter months supported the highest species richness, while maximum bird density was recorded in the month of March. The global population trend chart of the observed bird species showed that the maximum species belonged to the stable category (52 %, 55 species). The occurrence of 106 different bird species in the campus covering an area of 12 hectares clearly indicated that this area is suitable for avifauna. However, it should be mentioned that the area inside the college campus, as well as adjoining areas, are losing greenery to make space for the construction of buildings and other infrastructures. To add salt to the wound, various types of soil, air and noise pollution have directly or indirectly affected wildlife around the studied area, and avifauna is no exception in this regard. More intensified works on the avifauna of this region will surely enhance our understanding of their function in the ecosystem. The outcome of this kind of research might be beneficial for designing proper management strategies for different habitat types around the studied area.