Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 June 2023 | 15(6): 23449–23451
ISSN 0974-7907
(Online) | ISSN 0974-7893 (Print)
https://doi.org/10.11609/jott.8418.15.6.23449-23451
#8418 | Received 21
February 2023 | Final received 27 May 2023 | Finally accepted 30 May 2023
Predation of the Nicobar Shrew Crocidura nicobarica
by a Cattle Egret Bubulcus ibis
G. Gokulakrishnan
1 , C.S. Vishnu 2 & Manokaran
Kamalakannan 3
1,2 Wildlife Institute of India, Chandrabani, Dehradun, Uttarakhand 248001, India.
3 Zoological Survey of India,
Mammal & Osteology Section, New Alipore, Kolkata, West Bengal 700053,
India.
1 gokul7701@gmail.com, 2 vishnusreedharannair@gmail.com
(corresponding author), 3 kamalakannanm1@gmail.com
Editor: L.A.K. Singh, Bhubaneswar, Odisha, India. Date of publication: 26 June
2023 (online & print)
Citation: Gokulakrishnan, G., C.S.
Vishnu & M. Kamalakannan (2023). Predation of the Nicobar Shrew Crocidura nicobarica
by a Cattle Egret Bubulcus ibis. Journal of Threatened Taxa 15(6): 23449–23451. https://doi.org/10.11609/jott.8418.15.6.23449-23451
Copyright: © Gokulakrishnan 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: Self-funded.
Competing interests: The authors declare no competing interests.
Acknowledgements: We would like to thank G. Thikanna, Assistant sub-inspector of police, Campbell Bay,
for his help during the fieldwork.
Crocidura is the most speciose
currently recognized genus of mammals, with about 200 species (Burgin
et al. 2018). India is known for the presence of 12 Crocidura
species, distributed in the mainland and Andaman & Nicobar Islands (Kamalakannan et al. 2021). Currently, the Andaman &
Nicobar (AN) Islands are known to house only a single genus Crocidura
shrew, with five endemic species, namely, the Andaman Shrew C. andamanensis, the Andaman Spiny Shrew C. hispida, Jenkin’s Shrew C. jenkinsi,
the Nicobar Shrew C. nicobarica, and the most
recent discovery, the Narcondam Shrew C. narcondamica by Kamalakannan
et al. (2021), of which, C. nicobarica is only
known from the Great Nicobar Island (Molur et al.
2005; Menon 2014; Kamalakannan et al. 2021). Due to
the restricted insular habitat and the associated limited population size, the C.
nicobarica has been categorised
as ‘Critically Endangered’ by the IUCN Red List of Threatened Species (Molur 2016).
The Great Nicobar Island is the
largest of the 11 islands of the Nicobar group of Islands, situated at the
southernmost portion of the Andaman & Nicobar Islands, India (7.0346°N
& 93.7842°E). The Great Nicobar Island is home to several endangered and
endemic vertebrate fauna including the endangered Giant Leatherback Sea Turtle Dermochelys coriacea,
the endemic Nicobar Megapode Megapodius nicobariensis, and the endemic Nicobar Treeshrew Tupaia nicobarica (Saha 1980; Miller
1902; Pande et al. 1991; Kamalakannan
et al. 2020). The mammalian fauna of the Great Nicobar Island comprises mostly
bats and few non-volant mammals; the only known wild larger mammals are the
Wild Boar Sus scrofa
and the Nicobar Long-tailed Macaque Macaca fascicularis umbrosus (Bates
& Harrison 1997; Molur et al. 2002, 2005; Aul et al. 2014). The region is composed of deciduous,
moist, & evergreen forest, grasslands, and perennial rivers & streams
(Rodgers & Panwar 1988).
Insects and
small vertebrates are the primary diets of Cattle Egret Bubulcus ibis (Vega-Sánchez et al. 2022; Talbi et al. 2023), but predation of Crocidura
shrew is rarely observed. Here, we recorded a Cattle Egret preying on a shrew
at the littoral forests near Govind Nagar, Great
Nicobar Islands (6.9997°N & 93.9086°E; Figure 1); it was an opportunistic
observation, while watching the wetland birds. It was also observed that the
Cattle Egret flipped the shrew back up on the ground and kept on biting on the
head and neck regions with its bills and subsequently gobbled it down in one
motion. The bird was identified based on its white plumage, short, thick neck,
a sturdy yellow bill, and a hunched posture; the mammal was identified as
a shrew based on its long snout, grey dense dorsal pelage and medium-sized
tail, and further as C. nicobarica, because it
is the only shrew species known from the Great Nicobar Island (Image 1). Some
individuals of the C. nicobarica have
previously been observed in field surveys conducted at this location. The video
of the predation event can be accessed at the following link: https://osf.io/m7dxr/).
C. nicobarica is a comparatively large-sized
shrew (head and body length: 10.7–12 cm; tail length: 9–9.5 cm), characterised by a bristly sooty brown dorsal fur with a
slender tail (Menon 2014). They inhabit the leaf litter tropical moist
deciduous forests.
The equilibrium between foraging
gain and predation risk is the fundamental trade-off in animal life (Mazza et
al. 2019). Predation instances on shrews are rarely observed due to its
secretive behaviour, releasing pungent and musky odour when it is threatened (Nagorsen
1996; Jung 2016). Jung (2016) has reported a similar predation event on a
Western Water Shrew Sorex navigator by
a Belted Kingfisher Megaceryle alcyon from Yukon, Canada. Further studies on these
species’ natural history of both C. nicobarica
and B. ibis in the Great Nicobar Island will yield more information
about their potential interactions and their ecological relations and
functions.
For
figure & image - - click here for full PDF
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