Bird diversity in the coastal talukas of Sindhudurg District , Maharashtra , India

The list of birds of Sindhudurg coastal district was compiled based on primary and secondary information. All observations were made along the Sindhudurg coast, i.e., from Terekhol to Vijaydurg. Wetland birds were recorded during sampling while terrestrial birds were recorded opportunistically. Besides, we also collated bird occurrence records from published literature (including grey literature and online resources) to prepare a comprehensive list of birds for Sindhudurg coast. During our study, we recorded 283 species, and 24 more species were compiled from secondary sources. Altogether, 307 species belonging to 78 families and 22 orders were recorded from the Sindhudurg coast. Order Passeriformes was dominant with 111 species. Among the 307 species, four species are endemic to the Western Ghats. Three species of vultures had been reported earlier but two were not encountered in recent years. Great Knot (EN), Woolly-necked Stork (VU) and 14 other species (NT) fall under various threat categories of IUCN. Species richness was higher in Vengurla (256) followed by Malvan (247) and Devgad talukas. Construction of homestays, unregulated tourism in coastal areas, and conversion of natural habitats to meet increasing tourism are the major threats to the coastal avifauna of the district. A high species richness of birds in Sindhudurg coast is attributed to the availability of a wide array of habitats (coastal to woodlands with different degrees of anthropogenic disturbances). Considering the high species richness of birds and livelihood dependency of humans on the coastal zones, a few estuaries namely Mochemad, Karli and Mitbav estuaries may be recognized as community/ conservation reserve to manage the ecosystem sustainably for long-term conservation of these estuaries and sub-habitats therein. Also, those sites can be perceived as Important Bird and Biodiversity Areas of IBCN as they fulfill the IBA criteria.


INTRODUCTION
Sindhudurg District is located geographically on the southwestern side of the state of Maharashtra and recognised as one of the principal tourist destinations in the western coast of India. The increasing inflow of tourists to Sindhudurg coast and subsequent change in land use and land cover of the coastal area increase the pressure on coastal and marine biodiversity. Due to its potential for over-exploitation of coastal biodiversity, MoEF&CC and the Maharashtra Forest Department -Mangrove Cell in collaboration with UNDP and GEF have initiated the Sindhudurg project to mainstream coastal biodiversity into a production sector. As part of the program, we compiled primary and secondary bird occurrence data along the Sindhudurg coasts to signify bird diversity wealth and to identify crucial bird areas for the conservation of coastal birds.
Southwestern Maharashtra (Ratnagiri and Sindhudurg) received much attention for bird studies from both the early-time British ornithologists and postindependence workers. Studies in Sindhudurg District can broadly be grouped into three categories based on the extent of focal area and target birds, viz., Sindhudurg District as a landscape level (Vidal 1980;Gole 1994;Prasad 2006;Mahabal et al. 2011), small regions or localities level (Hume 1876;Abdulali 1940Abdulali , 1942Abdulali , 1983Madsen 1988;Pande 2002a;Lainer 2003;Katdare et al. 2004a; and single or small group of birds level (Katdare 2001;Pande 2001Pande , 2002bPande et al. 2001;Katdare et al. 2004b;Mahabal et al. 2007; Kambale et al. 2011;Rao et al. 2015). Vidal (1880) prepared the first comprehensive checklist on the birds of the Konkan region that included Sindhudurg District. Prasad (2006) included the Sindhudurg coast in his book on birds of western Maharashtra, though he did not specifically cover their local status. Studies by Khot (2016) included Malvan and Malagaon-Bagayat from Sindhudurg District but did not cover large parts of coastal zones in the Sindhudurg District. Patil et al. (2015) published a checklist for a single wetland (Pat Lake) in the district.
Considering this information and significance of the Sindhudurg coast, we have attempted to assess the local status, habitat association, sighting frequency and taluka-wise distribution of birds from the coastal talukas of Sindhudurg District based on primary and secondary observations from this region.

STUDY AREA
Sindhudurg 18 0 E) is located geographically on southwestern Maharashtra, and it was carved out from the erstwhile Ratnagiri District in 1981. The terrain is mostly gentlly undulating, and the elevation ranges from sea level to 120m. The state of Goa borders it in the south, Ratnagiri District in the north, Kolhapur District in the east and the Arabian Sea in the west (Fig. 1). Out of eight talukas, Vengurla, Malvan, and Devgad are coastal talukas. Coastal stretches of the district hold a wide-array of natural habitats, viz., sandy intertidal mudflats, mangroves, sandy beaches, rocky shoreline, and wooded forests. The coasts of Malvan Taluka has been recognized as Malvan Marine Wildlife Sanctuary in 1987. In addition to the coastal areas, we also did a survey at Pat Lake (freshwater lake), laterite grasslands (Chipi, Tondavali, Vengurla and other small grasslands), woodland areas within this buffer (moist deciduous forests and plantations), Vengurla rocks/islands (located nearly 6km from the coast), and man-modified sites (agriculture fields, saltpan and aquaculture ponds) (Images 1 & 2).
Pat Lake: Pat Lake is a freshwater lake located amid populated Pat Parule Village in Vengurla Taluka. This shallow lake with floating vegetation and mature trees on one side makes it a suitable habitat for several waterassociated birds including ducks and geese. Agricultural fields and a road surround the lake.
Laterite grasslands: These grasslands were formed during the mid-tertiary period and are part of Deccan Trap floodplain (Seshadri et al. 2016). The overall habitat comprises grasses, herbs, shrubs and stunted trees interspersed with agricultural fields and habitation. Grasslands are found along the coastal areas of Sindhudurg District. Some of the meadows are extensive in size and, offer potential foraging ground for raptors (e.g., Harriers Circus sp.) and nesting ground for grassland birds (e.g., Lapwings Vanellus sp. and Larks Alaudidae). We selected Chipi, Tondavali, Vengurla and other small grasslands in these talukas for studying raptor and other grassland dependent birds.
Woodlands including plantations: Fragmented patches of moist deciduous forest and plantations (mango, coconut, cashew and Casuarina) are found in mosaics among the human settlements. The natural forests are not intact but possess dense upper-storey and mid-storey cover.
Vengurla rocks: It is a group of small rocky offshore islands located around six kilometres from the Kochara 14168 village in Vengurla Taluka. In one of the islets, breeding activities of the Greater Crested Tern Thalasseus bergii, Bridled Tern Onychopriyon anaethetus and Roseate Tern Sterna dougallii have been reported (Lainer 2003). This rocky islet is partially covered with combinations of tall grasses and short herb species. The terns exploit the bare rocky portions of the island for nesting.
Man-modified habitats: Modified wetlands such as agriculture fields (largely paddy), saltpans and aquaculture ponds are found in patches throughout the coastal areas. Saltpan is practised in Vengurla Taluka on a minor scale. Aquaculture ponds are common along upstream regions of the district. Common aquaculture taxa are prawns and crabs.
These sites were sampled once a month and thus, we visited the whole stretch of Sindhudurg coast either by bike or jeep covering diverse terrestrial habitats (moist deciduous, grasslands, agriculture fields, commercial plantations) and inland wetland habitats (Pat Lake and puddles in grasslands during the monsoon) in the area. All observations on terrestrial birds were opportunistic. Quantitative data was collected only for wetland birds, which were the focus of the project but we recorded other birds as well to make a comprehensive list of birds. Bird surveys were carried out from December 2014 to December 2016. We made observations between 05.30h and 18.00h and conducted occasional night surveys for owls Strigiformes. Besides, we also conducted four offshore surveys to Vengurla rocks for pelagic birds using fishing boats. The number of days spent at each field site and taluka is provided in (Table 1). Although we used the Nikon spotting scope 20-60x for bird observation, sufficient photographs were taken to confirm species identities. Nearly 80% of our observations were photo documented. We did not collect abundance data for the terrestrial birds; thus, we categorised all the birds to December 2016 in the district, the distribution status of each bird species was categorized into five groups. Resident: Occurs in the district throughout the year. Winter Migrant: Species occur only during winter (September to May).
Passage Migrant: Species occurs in the study area for refueling their energy during onward and return migration.
Vagrant: Species is either not resident/not regular breeding or wintering migrant but has a few stray records.
Monsoon Migrant: Species occurs only during the monsoon.
Sindhudurg coast used to support three Critically Endangered species namely Red-headed Vulture Sarcogyps calvus, White-rumped Vulture Gyps bengalensis, and Indian Vulture G. indicus, one Endangered Great Knot Calidris tenuirostris, and Vulnerable Woolly-necked Stork Ciconia episcopus but during our study we could not record any vultures ( of total visits are given below (Image 3).

Interesting sight records
Northern Shoveler Anas clypeata: It was recorded twice: once in an aquaculture pond of Mitbav on 6 November 2016, and another on 8 November 2016 at Shiroda saltpans of Vengurla. On both occasions, the flock size was >10.
Ruddy Shelduck Tadorna ferruginea: One bird was seen in an aquaculture pond at Mitbav on 6 November 2016.
Painted Stork Mycteria leucocephala: A sub-adult bird was seen in a saltpan at Shiroda on 22 January 2015 (Image 3).
Amur Falcon Falco amurensis: One bird was seen in grassland at Vengurla on 20 November 2015 (Image 3).   Although we observed Steppe Eagle Aquila nipalensis, Grey-headed Fish Eagle Ichthyophaga ichthyaetus, Indian Spotted Eagle A. hastata, Red-necked Falcon Falco chicquera, Eurasian Sparrowhawk Accipiter nisus and Common Ringed Plover Charadrius hiaticula during our study, due to a lack of good quality photographs we excluded them from the list. The foraging guild of birds species in the district was dominated by insectivores (~49%) followed by piscivores (~18%), and omnivores and nectarivores showed least contribution (1% to 3%) ( Fig. 3).

DISCUSSION
Altogether, we collated 307 species from Sindhudurg coast, which represents nearly 84% of birds recorded from the Sindhudurg District as a whole (eBird 2019). Out of these 307 species, four are endemic to the Western Ghats. A multi-observer effort of 997 and 838 eBird lists yielded 364 and 340 bird species in Sindhudurg and Ratnagiri districts respectively while the present study recorded 283 bird species from 329 field days in the coastal areas indicating the high diversity of birds in these talukas. Despite inadequate sampling effort in the Western Ghats, year-round monitoring along the Sindhudurg coast raised the total species pool. A few stretches of natural forests (for example moist deciduous forests) in the district were surveyed, but intensive sampling was not conducted. Accordingly, the Journal of Threatened Taxa | www.threatenedtaxa.org | 26 July 2019 | 11(9): 14166-14186 14173 Cotton Pygmy-goose Nettapus coromandelianus  -Adbulali 1940, 1942, 1983, ED-Editors 1958, M-Madsen 1988 total species pool compiled here is only for the coastal regions of the district and more species might be added if one samples the forest areas of the district. Among the talukas surveyed, from Vengurla Taluka, a maximum richness of birds was recorded, and availability of mosaic of habitats within the coastal areas might be attributed for this pattern. The lower diversity of birds in Devgad Taluka can be associated with the presence of laterite grasslands along the coasts and an absence of a large extent of woody vegetation in the coastal areas. We also observed a few rare and under-recorded species of western Maharashtra, as mentioned in Prasad (2006) (Lainer 2003), Brown Booby Sula leucogaster (Jamalabad 2013), Blue-bearded Bee-eater Nyctyornis athertoni (Khot 2016), Red-throated Diver Gavia stellata (Avalaskar 2016), and Crimson-backed Sunbird Leptocoma minima (Shrikrishna Ramachandra Magdum pers. obs. 7.xii.2017) were reported from the Sindhudurg coast but not observed by us during the study. The vulture species had been distributed all over India but due to a recent population decline, their distribution range has shrunk to a few pockets, and this might be the reason for not encountering these species in all historical occurrence localities. Furthermore, as discussed earlier, less sampling in the northern Western Ghats might be the reason for missing a few forest dwelling species. Although we conducted coastal and offshore surveys, we did not carry out any surveys during the monsoon months because Bridled Tern is anticipated to occur in Vengurla rocks during the monsoon (Lainer 2003). In brief, less sampling in the Western Ghats and offshore, and rare nature of some species (e.g., Red-throated Diver) might be the reason for missing these birds.
Grey-headed Bulbul has been stated to occur in the Western Ghats, i.e., from Kanyakumari to Goa (Grimmett et al. 2011), but we observed this bird along the Sindhudurg coast. Prasad (2006) listed the Grey-headed Bulbul in Maharashtra's bird list, but comprehensive information about their distribution and occurrences within Maharashtra is not available. We saw it repeatedly (5 times in two locations: Hadi and Karli villages) in the forested areas along the Malvan and Vengurla coasts, and hence we speculate that the distribution range of this species in Maharashtra might be much more widespread than predicted. A survey of the Grey-headed Bulbul's population in abutting districts may be attempted to define the distribution range of this Near-threatened and endemic species of the Western Ghats. Vidal (1880) also had observed a few forest dwelling species, viz., Indian Scimitar Babbler, Blue-capped Rock Thrush, and Malabar Whistling Thrush in wooded habitats close to the coast.
Out of 283 species, 38% of them were migratory. Sindhudurg coast attracts migratory species especially transcontinental migratory birds like waders. Almost 68% of resident birds occur throughout the year in the district. The high richness of resident birds in Sindhudurg is attributed to the availability of the mosaic of habitats. It has also been observed in other studies that variation in bird populations among sites in different seasons and the same has been attributed to environmentally dependent factors such as the change in local and regional habitat conditions (Ericia et al. 2005).
Unregulated tourism and associated developments, sand mining, stray dogs and conversion of laterite grasslands are the major threats to the coastal avifauna in the district. Mochemad (95 species; 10,000 gulls of six species), Karli (117 species; 5,000 gulls of six species), Mitbav (103 species; 2,000 gulls of six species) estuaries, and grasslands such as Tondavali and Chipi (a breeding ground for lapwings, larks; alternative foraging ground for wintering shorebirds; foraging ground for wintering raptors) in Sindhudurg coast support a greater richness of terrestrial and wetland birds. Considering the high species richness of birds and livelihood dependency of humans on the coastal zones, a few estuaries namely Mochemad, Karli and Mitbav estuaries may be recognized as community reserve or conservation reserve to manage the ecosystem sustainably for longterm conservation of these estuaries and sub-habitats therein. Also, these three sites can be perceived as Important Bird and Biodiversity Areas of BirdLife International as they fulfill the IBA criteria.