Journal of Threatened
Taxa | www.threatenedtaxa.org | 26 February 2024 | 16(2): 24752–24759
ISSN 0974-7907
(Online) | ISSN 0974-7893 (Print)
https://doi.org/10.11609/jott.8452.16.2.24752-24759
#8452 | Received 26 March 2023 | Final received 26 January 2024 | Finally
accepted 01 February 2024
Waterbird count at Narathali
waterbody, Buxa Tiger Reserve in northern Bengal for
a decade (2009–2019) with a note on raptors
Sachin Ranade 1 &
Soumya Sundar Chakraborty 2
1,2 Vulture Conservation Breeding
Center, Buxa Tiger Reserve, Raja Bhat Khawa, Alipurduar, West Bengal
735227, India.
1 s.ranade@bnhs.org (corresponding
author), 2 soumyachkrbrty@yahoo.co.in
Editor: Anonymity requested. Date of
publication: 26 February 2024 (online & print)
Citation:
Ranade, S. & S.S. Chakraborty (2024). Waterbird
count at Narathali waterbody, Buxa
Tiger Reserve in northern Bengal for a decade (2009–2019) with a note on
raptors. Journal of Threatened Taxa 16(2): 24752–24759. https://doi.org/10.11609/jott.8452.16.2.24752-24759
Copyright: © Ranade & Chakraborty 2024. Creative Commons Attribution 4.0
International License. JoTT allows unrestricted use, reproduction, and
distribution of this article in any medium by providing adequate credit to the
author(s) and the source of publication.
Funding: None.
Competing interests: The authors declare no competing interests.
Author details: Mr Sachin Ranade works as a biologist for last 23 years, looking after the Vulture Conservation Program of BNHS in West Bengal and Assam. Mr. Soumya Sundar Chakraborty
serves as the centre manager at the Vulture Conservation Breeding Centre in West Bengal, looking after the breeding and reintroduction of the vultures.
Author contributions: SR planned the study, carried out field work in early years and wrote the manuscript. SSC carried out the field work during the later period.
Acknowledgements: The authors are grateful to the
authorities of Buxa Tiger Reserve for the kind
permission for the study. Thanks are due to the Bombay Natural History Society,
Mumbai and Royal Society for the Protection of Birds, UK for constant support
and encouragement.
Abstract: This study presents insights
from a comprehensive analysis of bird counts conducted at Narathali
waterbody in Buxa Tiger Reserve between 2009 and
2019. Thirteen bird species were monitored, including six wintering duck
species and seven resident waterfowl species. The population trends of these
birds remained relatively constant throughout the study period. Additionally,
the study documented raptor counts and compiled a checklist of waterbirds observed at the waterbody. These findings
enhance our understanding of bird population dynamics in this significant
habitat and provide valuable information for the conservation and management of
the Buxa Tiger Reserve.
Keywords: Bird population, checklist,
Common Moorhen,
Ferruginous Duck, population trend, raptors, wintering ducks.
Introduction
Long-term bird monitoring is essential for understanding
climate change, habitat dynamics, and population trends of the concerned taxa
(Gregory et al. 2009; Amat & Green 2010).
Northern Bengal has extensive forest cover but retains less water as the soil
is coarse and alluvial in nature
known as Bhabar soil. Despite heavy rainfall and the
presence of rivers and rivulets from the Himalaya, large water bodies are
scarce (Champion & Seth 2005). The Buxa Tiger
Reserve, representing northern Bengal’s rich biodiversity, harbours a small
waterbody ‘Narathali beel’
(Bengali: Beel= Lake) in the Alipurduar
district. This small waterbody supports diverse flora and fauna, serving as a
crucial habitat for winter migrants and resident waterbirds.
The present study provides a 10-year record of bird counts for selected species
at Narathali.
Study area
Narathali, a small water
body located at Buxa Tiger Reserve in the northeastern corner of West Bengal (26.5152°N, 89.7319°E),
is surrounded by rivers Dima, Bala, and Sankosh. While Sankosh remains
perennial, the other rivers are seasonal and lack consistent water throughout
the year. Due to the coarse nature of the soil, the terrain fails to retain
water, resulting Narathali as an exceptional
waterbody- attracting numerous waterfowl. This perennial water body, covering
an approximate length of 1.3 km and a width of 50 m, is encompassed by small
patches of grassland and woodland. The entire ecosystem serves as a crucial
habitat for both winter migratory waterbirds and land
birds. Various authors have presented bird inventories, with the initial study
on waterbirds conducted during 1999–2000, describing Narathali as stagnant water. At the culmination of the
rainy season, the water body submerges an area of 0.085 km2 (Image
1) within its boundaries, highlighting its significance as a dynamic habitat
for avian diversity in the region (Sivakumar & Prakash 2004).
Methods
Throughout the study period from 2009 to 2019, a total of
75 visits were carried out to the Narathali study
site during 10 winter seasons, covering the months of November to February.
Bird counts were conducted from a designated vantage point, primarily in the
morning (n = 69), with only a few counts taking place in the late afternoon (n
= 6). The researchers employed telescopes, binoculars, and photography to
observe and document the bird species. Accurate species identification was
ensured by referring to field guides, namely Grimmett
et al. (2011) and Rasmussen & Anderton (2012).
The study focused on monitoring the waterfowl species
present at the site, including six winter visitors (Gadwall Mareca
strepera, Northern Shoveler
Spatula clypeata, Northern Pintail Anas acuta, Common Teal Anas crecca,
Red-crested Pochard Netta rufina, and Ferruginous Duck Aythya
nyroca) and four resident species (Little Grebe Tachybaptus ruficollis,
Lesser Whistling-Duck Dendrocygna javanica, Cotton Teal Nettapus
coromandelianus, and Spot-billed Duck Anas poecilorhyncha). These waterfowl counts were diligently
maintained throughout the entire study duration. For each winter season, the
maximum count of each species was recorded, enabling the construction of graphs
illustrating the trends observed over the 10 years.
Furthermore, counts of three resident waterbird
species (Eurasian Moorhen Gallinula chloropus, Purple Swamphen
Porphyrio poliocephalus,
and Bronze-winged Jacana Metopidius indicus)
were specifically monitored for five years, covering the period from 2015 to
2019. Although a few additional waterfowl and raptor species were documented,
their limited sample sizes precluded their inclusion in the graph format. A
comprehensive bird list, with a specific emphasis on waterfowl and raptor
species, is provided in Table 1, serving as a valuable reference for future
analysis and documentation.
Results
The wintering
duck species at Narathali (Figure 1)
Gadwall Mareca strepera:
Common (Range 12–50, Average 26.9, Median 25, n = 10)
A widespread winter visitor in India, the species was
represented by 12 to 50 individuals at the water body. Its trend appears to be
constant.
Northern Shoveller Spatula clypeata:
Fairly Common (Range2–4, Average 2.8, Median 3, n = 5)
A widespread winter visitor in India, the species was
represented by two to four individuals at the water body. Its trend appears to
be constant.
Northern Pintail Anas acuta: Fairly Common (Range 2–10, Average 5.5,
Median 6, n = 6)
A widespread winter visitor in India, the species was
represented by two to 10 individuals at the water body. Its trend appears to be
constant.
Common Teal Anas crecca: Uncommon (Range 7–55, Average 27.5, Median
24, n = 4)
A widespread winter visitor in India, the species was
represented by seven to 55 individuals at the water body. Its trend appears to
be constant.
Red-crested Pochard Netta rufina:
Uncommon (Range 2–6, Average 3.6, Median 3, n = 5)
A widespread winter visitor in India, the species was
represented by two to six individuals at the water body. It’s interesting to
see that this species got attracted to Narathali in
the last three years of the observation.
Ferruginous Duck Aythya nyroca:
Common (Range 14–60, Average 35.2, Median 36, n = 10)
A Near-Threatened species (BirdLife
International 2019), a widespread winter visitor in India, the species was
represented by 14 to 60 individuals and the trend appears to be stable.
The resident duck
species and Grebe at Narathali (Figure 2)
Little Grebe Tachybaptus ruficollis:
Common (Range: 28–37, Average 31.4, Median 29, n = 5)
A widespread resident in India, the species was
represented by 28 to 37 individuals at the water body. Its trend appears to be
constant throughout the observations.
Lesser Whistling-Duck Dendrocygna javanica:
Common (Range 46–1000, Average 171.3, Median 74, n = 10)
A widespread resident in India, the species was
represented by 46 to 1000 individuals at the water body. Its trend appears to
be increasing. In 2019, a melanistic individual was noted in the flock (Image
2). During the last season, a population of about 1,000 individuals was noted.
Cotton Teal Nettapus coromandelianus:
Common (Range 5–33, Average 19, Median 20, n = 7)
A widespread resident in India, the species was
represented by 5–33 individuals at the water body. Its trend appears to be
constant.
Spot-billed Duck Anas poecilorhyncha: Common (Range 8–50, Average 28.9,
Median 26, n = 10)
A widespread resident in India, the species was
represented by 8–50 individuals at the water body. Its trend appears to be
constant.
Three resident waterfowl species monitored at Narathali (Figure 3)
Bronze-winged Jacana Metopidius indicus: Common
(Range 15–25, Average 19, Median 17, n = 5)
A widespread resident in India, the species was
represented by 15–25 individuals at the water body. Its trend appears to be
constant.
Purple Swamphen Porphyrio poliocephalus: Common (Range 5–8, Average 7, Median
8, n = 4)
A widespread resident in India, the species was
represented by 5–8 individuals at the water body. Its trend appears to be
constant.
Common Moorhen Gallinula
chloropus: Common (Range
40–183, Average 114, Median 81, n = 5)
A widespread resident in India, the species was
represented by 40–183 individuals at the water body. Its trend appears to be
declining at Narathali.
Other winter
visitor duck species observed at Narathali:
Mallard Anas platyrhynchos and Eurasian Wigeon Anas
penelope were sighted only in the years 2016–19.
The Falcated Duck Mareca
falcata (Image 3), Greylag Goose Anser
anser (2013–14) and Common Pochard Aythya ferina
(2014–15) were sighted during only one season.
Raptor species
There were nine
species of raptors recorded in the area as regular visitors. Two of them were
wetland dependent fish-eating eagles while rest seven species were not
dependent on wetlands yet were indicators of the biodiversity and quality of
the whole protected habitat. The Osprey Pandion haliaetus
was found during all of the 10 years. The water body supported one or two
individuals. The Grey-headed Fish-Eagle Haliaeetus
ichthyaetus was recorded in the years 2016, 17
and 19. The raptors Oriental Honey-buzzard Pernis
ptilorhynchus, Shikra Accipiter
badius and Crested Serpent-Eagle Spilornis cheela
were also sighted regularly. The Black Kite Milvus migrans
had a nest on a tree and could be sighted throughout the year for 10 seasons.
The Steppe Eagle Aquila nipalensis, Himalayan
Buzzard Buteo burmanicus,
and Black Eagle Ictinaetus malaiensis were winter visitors in the area and were
not uncommon.
Discussion
The water source, it’s quality and quantity matter a lot
for waterfowl. This specialized avifauna is one of the indicators of the health
of the ecosystem as well as pollution (Ormerod & Tyler 1993; Amat & Green 2010; Rajpar
& Zakaria 2011; Zhang & Ma 2011; Ogden et al. 2014). Allen et al.
(1996) had published a detailed checklist of birds in the Buxa
Tiger Reserve. There were 28 species of waterbirds
recorded at Narathali during 2000–01 (Sivakumar &
Prakash 2004). The current study recorded 53 avian species which is the result of
a longer duration of study period. It is interesting to note that during those
years, the Ferruginous Duck was noted at Rydak and
Dima rivers but not at Narathali. The species has
been attracted to the Narathali and has become a
regular visitor to the beel during 2009–19.
The Red-crested Pochard is also a regular visitor since 2017 but was absent
during 2009–2016. Sivakumar &
Prakash (2004) recorded the Goosander (Common Merganser) Mergus
merganser in Narathali, but we could not find it
in the habitat. We have noted the species in the Rydak
River at Bhutan-ghat in the Buxa
Tiger Reserve from 2015–2019. The Bhutan-ghat has
clear fresh water and icy torrential streams which is the favoured habitat of
the species (Ali & Ripley 1983; Rasmussen & Anderton 2012). Out of the
six wintering species monitored in this study, Ferruginous Duck is in the Near
Threatened category and the global population is on the decline (BirdLife International 2019). The rest five species
are in the Least Concern category. While globally, the Northern Shoveler and Northern Pintail populations are on the
decline, the trend in the population of Common Teal and Red-crested Pochard is
unknown, whereas the Gadwall population is increasing. In the case of the
resident waterfowl, the Little Grebe, Lesser Whistling-duck and Spot-billed
Duck are also in the Least Concern category but have the global population on
the decline, while the trend in the population of Cotton Teal is unknown (BirdLife International 2016). The highest bird count
of Lesser Whistling Duck shoot up to about 1,000 individuals during 2019 which
could be an abnormally high number, hence it was not considered in the graph
(Figure 2). The Population trend in Bronze-winged Jacana and Purple Swamphen is stable at Narathali,
both of them listed under the Least Concern category and their global
population trend is unknown. The Common Moorhen is also in the Least Concern
category and the global population is stable though the local population counts
are declining. One may conclude that most of these waterbirds
are common birds yet showing various degrees of decline (BirdLife
International 2016, 2021). In the case of Mallard, Eurasian Wigeon, Falcated Duck, and Greylag Goose, the species were known as
rare species in northern Bengal (Allen et al 1996; Rahmani
& Islam 2008).
The raptors at Narathali were
fairly constant, although low in number. The Osprey appeared during all 10
seasons indicating sufficient food supply for a couple of individuals in the
form of fish fauna. The Grey-headed Fish-Eagle has done a comeback in recent
years. Earlier, it was recorded as a fairly common species (Allen et al. 1996).
While the global population trend for the Osprey is increasing, the Grey-headed
Fish Eagle is on the decline whereas the Oriental Honey Buzzard, Shikra, and Crested Serpent Eagle have stable populations (BirdLife International 2021).
The observation and records of waterbirds
have been carried out for 10 winter seasons (November–February) from 2009 to
2019 for the first time in this region. The trends in the population are fairly
stable. One of the reasons the species are attracted to this water body could
be the poor condition of water bodies in human habitation. The Rasik beel –a waterbody in the
Cooch Behar district is located about 30 km from Narathali.
It is an interesting example of attracting migratory waterbirds
by scientific management of the waterbody and the waterfowl numbers varying
accordingly. The waterbody supported Sarus Crane (Antigone
antigone) till 1990 (Das et al. 2013). In the
first-ever systematic bird survey, 138 species of birds were recorded out of
which 88 were water dependent bird species. This survey was carried out by
Himalayan Nature and Adventure Foundation (HNAF 2001). Out of 165 bird species,
67 water-dependent bird species were recorded by Das et al. (2011). The overall
number of bird species in the checklist increased, but the number of water bird
species declined which is a cause of concern. There is a possibility of the
swing of bird populations from Rasik beel to Narathali or similar
locations in protected areas, and a future extensive study on the effects of
urbanization around Buxa Tiger Reserve is necessary
(Wang et al 2021). In the case of Narathali, the
Forest department maintains the water body by removing the Water Hyacinth Eichhornia crassipes that
would clog it. Removal of the clogging vegetation before the winter seems to
attract the population of migratory waterbirds. We
believe the slight peak in the bird count of all wintering ducks was due to the
timely removal of the Water Hyacinth in the year 2014-15 (Figure 1). This
ten-year study emphasizes importance of wetlands in protected areas for
migratory and resident waterbirds.
Table 1. List of birds
at Narathali Waterbody in Buxa
Tiger Reserve, West Bengal.
|
|
Family |
Common name |
Scientific name |
Abundance |
Migrant/Resident status |
|
1 |
Podicipedidae |
Little grebe |
Tachybaptus ruficollis |
Common |
Resident |
|
2 |
Phalacrocoracidae |
Little cormorant |
Microcarbo niger |
Common |
Resident |
|
3 |
Anhingidae |
Darter |
Anhinga melanogaster |
Uncommon |
Resident |
|
4 |
Ardeidae |
Little Egret |
Egretta garzetta |
Fairly Common |
Resident |
|
5 |
Ardeidae |
Grey Heron |
Ardea cinerea |
Rare |
Winter Visitor |
|
6 |
Ardeidae |
Purple Heron |
Ardea purpurea |
Rare |
Resident |
|
7 |
Ardeidae |
Great Egret |
Egretta alba |
Uncommon |
Resident |
|
8 |
Ardeidae |
Intermediate Egret |
Egretta intermedia |
Uncommon |
Resident |
|
9 |
Ardeidae |
Eastern Cattle Egret |
Bubulcus coromandus |
Common |
Resident |
|
10 |
Ardeidae |
Indian Pond-Heron |
Ardeola grayii |
Common |
Resident |
|
11 |
Ardeidae |
Yellow Bittern |
Ixobrychus sinensis |
Rare |
Resident |
|
12 |
Ardeidae |
Chestnut Bittern |
Ixobrychus cinnamomeus |
Rare |
Resident |
|
13 |
Ciconiidae |
Asian Openbill-Stork |
Anastomus oscitans |
Common |
Resident |
|
14 |
Ciconiidae |
Lesser adjutant stork |
Leptoptilos javanicus |
Fairly Common |
Resident |
|
15 |
Anatidae |
Lesser Whistling-Duck |
Dendrocygna javanica |
Common |
Resident |
|
16 |
Anatidae |
Greylag Goose |
Anser anser |
Irregular |
Winter Visitor |
|
17 |
Anatidae |
CottonTeal |
Nettapus coromandelianus |
Common |
Resident |
|
18 |
Anatidae |
Gadwall |
Mareca strepera |
Common |
Winter Visitor |
|
19 |
Anatidae |
Falcated Duck |
Mareca falcata |
Irregular |
Winter Visitor |
|
20 |
Anatidae |
Eurasian Wigeon |
Mareca penelope |
Uncommon |
Winter Visitor |
|
21 |
Anatidae |
Mallard |
Anas platyrhynchos |
Uncommon |
Winter Visitor |
|
22 |
Anatidae |
Indian Spot-billed Duck |
Anas poecilorhyncha |
Common |
Winter Visitor |
|
23 |
Anatidae |
Northern Shoveler |
Spatula clypeata |
Fairly Common |
Winter Visitor |
|
24 |
Anatidae |
Northern Pintail |
Anas acuta |
Fairly Common |
Winter Visitor |
|
25 |
Anatidae |
Common Teal |
Anas crecca |
Uncommon |
Winter Visitor |
|
26 |
Anatidae |
Red-crested Pochard |
Natta rufina |
Uncommon |
Winter Visitor |
|
27 |
Anatidae |
Common Pochard |
Aythya ferina |
Irregular |
Winter Visitor |
|
28 |
Anatidae |
Ferruginous Duck |
Aythya nyroca |
Common |
Winter Visitor |
|
29 |
Accipitridae |
Oriental Honey-Buzzard |
Pernis ptylorhynchus |
Rare |
Resident |
|
30 |
Accipitridae |
Black-winged Kite |
Elanus caeruleus |
Rare |
Resident |
|
31 |
Accipitridae |
Black Kite |
Milvus migrans |
Common |
Resident |
|
32 |
Accipitridae |
Grey-headed Fish-Eagle |
Ichthyophaga ichthyaetus |
Rare |
Resident |
|
33 |
Accipitridae |
Crested Serpent-Eagle |
Spilornis cheela |
Common |
Resident |
|
34 |
Accipitridae |
Shikra |
Accipiter badius |
Uncommon |
Resident |
|
35 |
Accipitridae |
Himalayan Buzzard |
Buteo burmanicus |
Irregular |
Winter Visitor |
|
36 |
Accipitridae |
Black Eagle |
Ictinaetus malayansis |
Uncommon |
Winter Visitor |
|
37 |
Accipitridae |
Greater Spotted Eagle |
Clanga clanga |
Irregular |
Winter Visitor |
|
38 |
Accipitridae |
Steppe Eagle |
Aquila nipalensis |
Rare |
Winter Visitor |
|
39 |
Pandionidae |
Western Osprey |
Pandion haliaetus |
Common |
Winter Visitor |
|
40 |
Falconidae |
Collared Falconet |
Microhierax caerulescens |
Rare |
Resident |
|
41 |
Falconidae |
Common Kestrel |
Falco tinnunculus |
Rare |
Winter Visitor |
|
42 |
Falconidae |
Red-headed Falcon |
Falco chicquera |
Rare |
Resident |
|
43 |
Rallidae |
White-breasted Waterhen |
Amaurornis phoenicurus |
Common |
Resident |
|
44 |
Rallidae |
Purple Swamphen |
Porphyrio poliocephalus |
Common |
Resident |
|
45 |
Rallidae |
Common Moorhen |
Gallinula chloropus |
Common |
Resident |
|
46 |
Rallidae |
Eurasian Coot |
Fulica atra |
Common |
Resident |
|
47 |
Jacanidae |
Pheasant-tailed Jacana |
Hydrophasianus chirurgus |
Rare |
Resident |
|
48 |
Jacanidae |
Bronze-winged Jacana |
Metopidius indicus |
Common |
Resident |
|
49 |
Charadriidae |
Red-Wattled
Lapwing |
Vennalus indicus |
Common |
Resident |
|
50 |
Alcedinidae |
White-throated Kingfisher |
Halcyon smyrnensis |
Common |
Resident |
|
51 |
Scolopacidae |
Common Greenshank |
Tringa nebularia |
Common |
Winter Visitor |
|
52 |
Scolopacidae |
Green Sandpiper |
Tringa ochropus |
Common |
Winter Visitor |
|
53 |
Scolopacidae |
Wood Sandpiper |
Tringa glareola |
Common |
Winter Visitor |
Abundance categories based on
sightings in the seasons: Common—8–10 times out of 10 seasons | Fairly
common—6–8 times out of 10 seasons | Uncommon—4–5 times out of 10 seasons |
Rare—2–3 times out of 10 seasons | Irregular—once in ten seasons.
For
figures & images - - click here for full PDF
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