Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 October 2023 | 15(10): 23990–23995
ISSN 0974-7907
(Online) | ISSN 0974-7893 (Print)
https://doi.org/10.11609/jott.8680.15.10.23990-23995
#8680 | Received 10 August 2023 | Final received 14 September 2023 |
Finally accepted 16 October 2023
From the Arabian Peninsula to
Indian shores: Crab Plover Dromas ardeola Paykull, 1805 (Aves:
Charadriiformes: Dromadidae)
breeding at Point Calimere, India
H. Byju
1, N. Raveendran 2 & K.M. Aarif
3
1 Centre of Advanced Study in
Marine Biology, Annamalai University, Parangipettai
Tamil Nadu 608502, India.
2 Iragukal Amritha
Nature Trust, 61, Ramachandra Thadaga Street, Thirumangalam, Madurai, Tamil Nadu 625706, India.
3 Terrestrial Ecology, Centre for
Environment and Marine Studies, Research Institute, King Fahd University
of Petroleum & Minerals, Dhahran, 31261, Kingdom of Saudi
Arabia.
1 byjuhi@gmail.com
(corresponding author), 2 Iant.ravee@gmail.com,
3 achuarif@gmail.com
Editor: Anonymity requested. Date of
publication: 26 October 2023 (online & print)
Citation: Byju, H., N. Raveendran & K.M. Aarif (2023). From the Arabian Peninsula to Indian
shores: Crab Plover Dromas ardeola Paykull, 1805 (Aves: Charadriiformes: Dromadidae)
breeding at Point Calimere, India. Journal of Threatened Taxa 15(10): 23990–23995. https://doi.org/10.11609/jott.8680.15.10.23990-23995
Copyright: © Byju et al. 2023. 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 contributions: BH—conceptualization, writing and editing; RN—data compilation, writing; KMA—writing, editing and maps.
Acknowledgements: We are grateful to Mrs. Guyomini Panagoda, University of
Colombo, for the inputs that led to this discovery. The boatman RBS and Mr Vedhamani Murugaiyan who
accompanied us as well as guided us in field visits requires special mention of
gratitude.
Abstract: Crab Plover Dromas
ardeola is endemic to the subtropical and
tropical coastlines of the Indian Ocean. It breeds along the eastern coasts of
Africa, the Persian Gulf, and southern coasts of the Arabian Peninsula; occurs
also in the western Madagascar and most islands northwards to Seychelles. It is
a winter visitor to Pakistan, Gujarat, and peninsular India, Andaman &
Nicobar Islands, Lakshadweep, northern Sri Lanka, Maldives, and a vagrant to
Bangladesh. The objective of this study was to assess the breeding records of
the Crab Plover in Point Calimere. After some
preliminary surveys and interactions with local birders, between June and
August 2023, boat surveys and foot surveys were carried out in the Great Vedaryanam Swamp (GVS) and nearby islets to document the
presence of Crab Plover and locate its nests. The presence of five nests of D.
ardeola was recorded in Manaaran Theevu islet near Siruthalaikkadu of GVS. This observation marks the first
documentation of breeding of Crab Plover in the Indian subcontinent. In the
context of species conservation within the peninsular Indian region, there is a
need for comprehensive and continuous monitoring of breeding sites.
Keywords: Bird migration, breeding colony,
nesting site, shorebirds, winter visitor.
Introduction
The Crab Plover Dromas ardeola, belonging to the family Dromadidae,
is a distinctive and enigmatic species endemic to the subtropical and tropical
coastlines of the Indian Ocean. Crab
Plovers are winter visitors on the coasts of Pakistan, Gujarat, and peninsular
India, Andaman & Nicobar Islands, Lakshadweep, northern Sri Lanka,
Maldives, and Bangladesh. Crab Plovers
are known to breed on islands in the Arabian Gulf and Africa including the
United Arab Emirates, Masirah Island in Oman, Kuwait,
Iran, Saudi Arabia, Yemen, Eritrea, Egypt, Sudan, and the islets of northern
Somalia (Cramp et al. 1983; De Marchi et al. 2006;
Scott 2007; Delany et al. 2009; Jennings 2010; Tayefeh
et al. 2011; Javed et al. 2012; Tayefeh
et al. 2013; Bom & Al-Nasrallah 2015; Abdelhafez et al. 2020). These birds form colonies and
engage in nesting activities from April to August. They lay a single egg within
a self-excavated burrow located in a flat sandbank (Morris 1992; Hockey 1995; Rands 1996). The nest is an unlined chamber at the end of a
burrow 100–250 cm long excavated into the sandy substrate (Rands
1996). Within these burrows, the female lays a single egg. This nesting
strategy provides the necessary protection and safety for the egg during the
incubation period and the burrows appear to be useful for partial solar
incubation (De Marchi et al. 2008) and extended
foraging on the tidal food resource (De Marchi et al.
2015a). The chicks are semi-nidifugous (Cramp et al. 1983; Hockey &
Aspinall 1997), and remain within the nest burrow
until fledging. It has been found that Crab Plover nests shift annually due to
various reasons, like the suitability of the sand bank for digging burrows
(Hockey & Aspinall 1997; Chiozzi et al. 2011);
easy access to and departure from colony sites that explain the preference for
nest sites near to the sea (Cramp et al. 1983) and burrows near the base of
shrubs to avoid collapse of nests in loose soil (Bourgeois et al. 2008; Chiozzi et al. 2011). The breeding biology of the Crab
Plover incorporates features that are unique among shorebirds. It is the only
shorebird that nests in self-dug burrows, the only shorebird that lays a white
egg (Rands 1996; Hockey & Aspinall 1997), and the
waterbird species known to provide food to its chicks
well after the post-reproductive migration and over-wintering (De Sanctis et al. 2005).
While the species was never recorded as a breeder in the Indian
subcontinent, a hint of possible breeding has come from the preliminary results
of research with satellite-tagged crab plovers. On 16 November 2022, in a talk
given by Ms. Guyomini Panagoda,
University of Colombo, in the Asian Flyways Collaborative for Waterbirds (AFCoW) platform about
the Central Asian Flyway (CAF) and bird migratory pathways in Sri Lanka,
mentioned about five Crab Plover individuals being satellite tagged and colour banded for migratory studies (Appendix 1). The
findings that were shared on the platform shed more light on the fact that one
of the green colour flagged (International colour coding used for Sri Lanka for migratory studies in
CAF) and satellite-tagged Crab Plover stayed in the Point Calimere
region from June to August 2022 after moving through the Gulf of Mannar (GoM) region of India from
Sri Lanka. An attempt was made by the Bombay Natural History Society (BNHS)
team in 2022 to trace the same bird, which turned out to be futile.
Subsequently, the same male bird was reported with a juvenile on 30 August
2022, in Talai Mannar, Sri
Lanka, which further emphasized that the Crab Plover has a potential breeding
location at Point Calimere even if earlier studies by
the BNHS reported that there has been no Crab Plover record from Point Calimere since 2003 (Balachandran & Thirunavukarasu
2009). The objective of the present study was to find the potential breeding
grounds of Crab Plover in the Palk Bay region of Point Calimere.
Study Area and Methods
The Great Vedaryanam Swamp (GVS) and its adjacent areas, covering
approximately 350 km2, are situated along the Bay of Bengal,
specifically on the low promontory of the Coromandel coast within the Nagapattinam, Thiruvarur, and Thanjavur districts of Tamil Nadu, India. The GVS stretches
for about 48 km from east to west, parallel to the Palk Strait and is separated
from it by a sandbank. Its extents are about 10 km from north to south, and it
is broadest in the east, narrowing to about 8 km in the central part and 6 km
at the western end. On the east of the GVS lies the Point Calimere
Wildlife Sanctuary known for both migratory and resident bird species. GVS is a
coastal wetland featuring a rich diversity of habitats and ecological
attributes. These include inter-tidal salt marshes, forested wetlands,
mangroves, and brackish to saline lagoons (Image 2 & 3). Additionally, six
freshwater inlets connected to the Cauvery River flow into the swamp,
contributing to its unique ecosystem, complete with islands and mangrove
forests. Notably, the eastern sand dunes within the GVS have largely been
stabilized by Prosopis vegetation, while the higher dunes in the
northeastern region have dense tropical dry evergreen forests. The climate in
GVS is characterized by hot and humid summers and rainy winters. Most of the
precipitation occurs during the northeast monsoon season, typically from
October to December, contributing to an average rainfall of 1,280 mm in the
area. The study area had most of the
prey species for Crab Plovers including mudskippers, juveniles of Portunus portunus,
and Fiddler Crabs (Uca spp.)
(Balachandran 1995; Byju 2020).
We did some
preliminary surveys with birders around the area about frequent visits,
sightings, and the presence of Crab Plover from the area for the last two
decades. The Crab Plover was regularly documented from Manoli
and Hare islands of GoM (Balachandran 1995; Byju 2020), the nearby wintering site on the southeastern
coast. With the collected information, we narrowed down the search with three
expeditions from June to August 2023 to three islets in the GVS near Siruthalaikadu. Initially, bird surveys were done by boat.
Later when the species was located, foot surveys were performed to locate the
precise nesting location.
Results
Our
observations confirm the breeding records of Crab Plover on Manaaran
Theevu (one of the small islets of GVS; 10.2792°N,
79.7264°E), next to the Chellakanni River canal on
the southeast coast of India (Image 1). This area is a flat, sandy island with
large mudflats extending towards the landmass of Siruthalaikadu.
We recorded that the vegetation is entirely composed of grasses and herbs less
than 100 cm tall on the edges of the islets towards the landside with
intermittent halophytes on the mudflat, along with Avicennia
mangroves and
the invasive Prosopis juliflora. On our first
survey on 30 June 2023, we counted 13 individuals on the mudflats but could not
find any nests. Since as earlier cited, the bird has not been reported from GVS
or Point Calimere for more than three decades and
this sighting happened during the breeding period. We continued the monitoring
to the next month too. The Crab Plover colony was first discovered on 14 July
2023, followed by the next visit on 8 August 2023. On this survey, close to the
sea, we identified and documented five nests as a small colony covering a small
area of 100–150 m2 (Image 4 & 5). As we did not want to
disturb the nesting, observation was carried out from a safe distance for birds
using binoculars (Nikon Monarch7, 10 x 42) and spotting scope (Vanguard HD 82
A).
We could
not find any adult-juvenile interaction. We could only spot adult birds near
the burrows at times. On 8 August, we recorded some broken egg shells, possibly
of Crab Plovers, on the soil surface amid the burrows indicating egg laying (Abdelhafez et al. 2020). We also recorded one green colour flagged bird from Sri Lanka (Image 6 & 7) along
with a single juvenile in the August survey on the islet. We could not find any
other nesting sites on the nearby islets during the boat surveys.
Discussion
Despite the
notable records of Crab Plover breeding in the Arabian Peninsula, the finding
of the first confirmed breeding ground in India, well outside the species’
primary range, marks a significant discovery. This colony is likely a new one
as suggested by the lack of previous records and by the small number of nests,
compared to the number of nests in the colonies in the Middle East (Bom & al-Nasrallah 2015). It is interesting to note
that the new colony is located in an area with a comparatively high rainfall
(on average 1,366 mm) and is therefore more vegetated that the colonies around
the Arabian Peninsula (Manikannan et al. 2011; Sathishkumar et al. 2023), but breeding is anyway during
the dry season as elsewhere (De Marchi et al. 2015b).
While Crab
Plover is a ‘Least Concern’ species as per the IUCN Red List (BirdLife International 2023), their breeding range is
notably limited, consisting of only a few colonies, the majority, if not all,
of which are located in an area facing rapid exploitation, significant coastal
alterations, and pollution (Sheppard et al. 2010; Sale et al. 2011). This
environmental context renders the species highly susceptible to threats, as the
destruction of a single breeding colony can impact a substantial portion of the
overall breeding habitat for the entire population.
Due to our
intermittent presence in sight of the breeding colony, we did not record any
direct threat, as the collection of eggs by fishermen, which was reported from
other nesting sites, like in the Arabian Peninsula (Brown et al. 1991; Rands 1996). We did not record on the breeding islet the
presence of dangerous rats and cats (De Marchi et al.
2006; Javed et al. 2012) but we found indirect
evidence of the presence of Wild Boar Sus scrofa and Golden Jackal Canis
aureus, which could be a threat to the breeding of this species. An
indirect threat we perceived, after informal interaction with the local
fishermen community, is the access to outside people for tourism, especially
during the hottest months of June and July, which coincide with the breeding
time of the Crab Plover. As most of the GVS is not a protected area and the
breeding island can’t be reached on foot, most of the tourists certainly rent
local fishermen’s boats in order to illegally spend the whole day on the
islets. Moreover, islands are used by fishermen for drying the nets as well as
staying for the night for early morning fishing activities. The Crab Plover
nesting colonies are found in the vegetated area near the shores where
fishermen also land their small fishing vessels, hence the chances of walking
over the burrows and the breakages of eggs could happen. Last, as only the
eastern tip of the GVS is protected by the Point Calimere
Wildlife Sanctuary, the largest part of the insular and intertidal ecosystems
of the GVS is threatened by hunting, by the development of salt pans and prawn
farms, and by the spread of invasive species like Prosopis juliflora. The result is a significant decrease in
avian species diversity and abundance compared to historical records (Rashiba et al. 2022).
Considering
the location of the Crab Plover colony of the GVS in relation to the main
breeding range of the species, it is important to follow the fate of the colony
in the coming years and monitor its increase in size or its eventual demise. If
possible, access to this area to tourists and fishermen should be curtailed
during the breeding season by the concerned authorities. The information
collected will be instrumental in enhancing our understanding of the species’
breeding strategies and furthering conservation efforts to ensure the
preservation of this unique avian species in its limited range.
Appendix 1. (The access to AFCoW webpage: https://afcow.org/news/. In case you do not have access
to YouTube: https://www.bilibili.com/video/BV1ad4y1b7ZU/?share_source=copy_web&vd_source=c53d6edc8ddb6324ee27fd5fa135ece7(Timings 26.22-30.37).
For images
- - click here for full PDF
References
Abdelhafez, M.S.,
K.F. Abd El-Wakeil & S.A. Saber (2020). First
record of Crab Plover (Dromas ardeola) nesting in Egypt. Egyptian Academic
Journal of Biological Sciences 12(2): 149–154. https://doi.org/10.21608/eajbsz.2020.125274
Balachandran, S. (1995). Shorebirds of the Gulf of Mannar Marine National Park, Tamil Nadu. Journal of the
Bombay Natural History Society 92(3): 303–313.
Balachandran, S. & V. Thirunavakarasu
(2009). Field guide to the birds of Point Calimere. Bombay
Natural History Society. Published by Tamil Nadu Forest Department, 92 pp.
BirdLife
International (2023). Species factsheet: Dromas
ardeola. Downloaded from
http://datazone.birdlife.org/species/factsheet/crab-plover-dromas-ardeola on 20
August 2023
Bom, R.A.
& K. Al-Nasrallah (2015). Counts and breeding biology of Crab Plovers Dromas ardeola on Bubiyan Islands, Kuwait, in 2012–2014. Wader Study
122(3): 212–220. https://doi.org/10.18194/ws.00022
Bourgeois, K., E. Vidal, V. Comor, J. Legrand
& S. Dromzee (2008).
Colony-site selection drives management priorities for Yelkouan
shearwater populations. Journal of Wildlife Management 72(5):
1188–1193. https://doi.org/10.2193/2007-052
Brown, J.N.B., M. Verhage & R.P. Morris
(1991). Crab Plovers on Jazirat Abu al Abyad. Tribulus 1:
13–15.
Byju, H.
(2020). Interesting foraging behaviour of Crab Plover
in Manali Island, Gulf of Mannar, India. Zoo’s
Print 35(12): 25–28.
Cramp, S., K.L.E. Simmons, D.C. Brooks, N.J. Collar, E. Dunn, R. Gillmor
& P.J.S. Olney (1983). Handbook of the birds of Europe, the Middle
East and North Africa. Vol. 3. The Birds of the Western Palearctic: Waders
to Gulls. Oxford University Press, UK, 1000 pp.
Chiozzi, G., G.D. Marchi & D. Semere (2011).
Coloniality in the Crab Plover Dromas ardeola does not depend on nest site limitation. Waterbirds 34(1): 77–81. https://doi.org/10.1675/063.034.0109
Delany, S., D. Scott, A.T.F. Helmink, T.
Dodman, S. Flink, D. Stroud & L. Haanstra (2009). An atlas of
wader populations in Africa and Western Eurasia. Wetlands
International, Wageningen, 524 pp.
De Marchi, G., G. Chiozzi,
D. Semere, P. Galeotti, E. Boncompagni & M. Fasola
(2006). Nesting, overwintering, and conservation of the Crab Plover
Dromas ardeola in
central Eritrea. Ibis 148(4): 753–764. https://doi.org/10.1111/j.1474-919X.2006.00572.x
De Marchi, G., G. Chiozzi
& M. Fasola (2008). Solar incubation cuts down parental care in a burrow-nesting tropical shorebird, the Crab plover Dromas ardeola. Journal of Avian Biology 39(5): 484–486.
https://doi.org/10.1111/j.0908-8857.2008.04523.x
De Marchi, G., G. Chiozzi,
G. Dell’Omo & M. Fasola
(2015a). Low incubation
investment in the burrow-nesting Crab
Plover Dromas ardeola permits extended foraging on a tidal food resource.
Ibis 157(1): 31–43. https://doi.org/10.1111/ibi.12208
De Marchi, G., G. Chiozzi,
D. Semere, Y. Mebrahtu,
F.H. Tayefeh, M. Almalki
& M. Fasola (2015b). Food
abundance explains the breeding season of a tropical shorebird, the Crab Plover
Dromas ardeola.
Ostrich 86(1–2): 53–64. https://doi.org/10.2989/00306525.2015.1030465
De Sanctis, A., L. Biddau
& M. Fasola (2005). Post
migratory care of young by Crab Plovers Dromas
ardeola. Ibis 147(3): 490–497. https://doi.org/10.1111/j.1474-919x.2005.00419.x
Hockey, P.A.R. (1995). Waders of Southern Africa. Struik Publishing House, Cape Town, 288 pp.
Hockey, P.A.R. & S.J. Aspinall (1997). Why do Crab
Plovers Dromas ardeola
breed in colonies? Shorebird Study Group Bulletin 82: 38–42.
Javed, S., S.B.
Khan, S.C. Tourenq, F. Launay & J. Merritt
(2012). Nesting, distribution and conservation of the Crab Plover, Dromas ardeola, in
the United Arab Emirates. Zoology in the Middle East 56(1): 9–18. https://doi.org/10.1080/09397140.2012.10648935
Jennings, M.C. (2010). Atlas of the breeding birds of Arabia. Fauna
of Arabia, King Abdulaziz City for Science and
Technology, Vol 25. 751 pp.
Manikannan, R., S. Asokan & A.H.M.S. Ali (2011a). Seasonal
variations of physico-chemical properties of the
Great Vedaranyam Swamp, Point Calimere
Wildlife Sanctuary, South-east coast of India. African Journal of
Environmental Science and Technology 5(9): 673–681.
Morris, R.P. (1992). Observations on a colony of Crab Plovers D.
ardeola in Abu Dhabi. Sandgrouse 14:
34–47.
Rashiba, A.P., K. Jishnu, H. Byju, C.T. Shifa, J. Anand, K. Vichithra, Y.
Xu, A. Nefla, A., S.B. Muzaffar, K.M. Aarif & K.A. Rubeena (2022). The paradox
of shorebird diversity and abundance in the West Coast and East Coast of India:
A comparative analysis. Diversity 14: 885. https://doi.org/10.3390/d14100885
Rands, M.R.W.
(1996). Family Dromadidae (Crab Plover), pp. 302–306.
In: del Hoyo, J., A. Elliott and J. Sargatal (eds.). Handbook of the Birds of the World.
Vol. 3. Hoatzin to Auks. Lynx Edicions,
Barcelona, Spain.
Sale, P.F., D.A. Feary, J.A. Burt, A.G.
Bauman, G.H. Cavalcante, K.G. Drouillard, B. Kjerfve, E. Marquis, C.G. Trick & P. Usseglio (2011). The
growing need for sustainable ecological management of marine communities of the
Persian Gulf. Ambio 40: 4–17. https://doi.org/10.1007/s13280-010-0092-6
Sathishkumar, S., S. Arandhara & N. Baskaran (2023). Effect of
ecological factors on the grass dynamics at Point Calimere
Wildlife Sanctuary, India. Journal of Threatened Taxa 15(5):
23190–23199. https://doi.org/10.11609/jott.8277.15.5.23190-23199
Sheppard, C., M. Al-Husiani, F. Al-Jamali, F. Al-Yamani, R. Baldwin, J. Bishop, F. Benzoni,
E. Dutrieux, N.K. Dulvy,
S.R. Durvasula, D.A. Jones, R. Loughland,
D. Medio, M. Nithyanandan, G.M. Pilling,
I. Polikarpov, A.R. Price, S. Purkis,
B. Riegl, M. Saburova, K.S.
Namin, O. Taylor, S. Wilson & K. Zainal (2010). The Gulf: A young
sea in decline. Marine
Pollution Bulletin 60(1): 13–38. https://doi.org/10.1016/j.marpolbul.2009.10.017
Scott, D.A. (2007). A review of the status of the breeding waterbirds in Iran in
the 1970s. Podoces 2(1): 1–21.
Tayefeh, F.H., M. Zakaria, H. Amini, S. Ghasemi & M. Ghasem (2011). Breeding waterbird populations of the islands of the northern Persian Gulf,
Iran. Podoces 6: 49–58.
Tayefeh, F.H., M. Zakaria, G. De Marchi, H. Amini, A. Moradi, P. Ahmadpour & S. Ghasemi
(2013). Breeding biology of the Crab Plover
(Dromas ardeola)
on the Mond Islands, Northern
Persian Gulf, Iran. Waterbirds 36(4): 448–462.
https://doi.org/10.1675/063.036.0402