Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 June 2022 | 14(6): 21315–21317
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
https://doi.org/10.11609/jott.7896.14.6.21315-21317
#7896 | Received 24 February 2022 | Final
received 18 May 2022 | Finally accepted 25 May 2022
New breeding site record of
Oriental White Ibis Threskiornis melanocephalus (Aves: Threskiornithidae)
at Thirunavaya wetlands, Kerala, India
Binu Chullakattil
Department of Zoology, NSS
College, Manjeri College (PO), Manjeri,
Malappuram, Kerala 676122, India.
Editor: H. Byju, Coimbatore, Tamil Nadu, India. Date
of publication: 26 June 2022 (online & print)
Citation: Chullakattil,
B. (2022). New breeding site record of
Oriental White Ibis Threskiornis melanocephalus (Aves: Threskiornithidae)
at Thirunavaya wetlands, Kerala, India. Journal of Threatened Taxa 14(6): 21315–21317. https://doi.org/10.11609/jott.7896.14.6.21315-21317
Copyright: © Chullakattil
2022. 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 author
declares no competing interests.
Acknowledgements: I am grateful to the NGO Re Echo
standing for the conservation of Tirunavaya wetland
and the local people of Tirunavaya for their sincere
support during the study period.
The Oriental White Ibis Threskiornis
melanocephalus (Latham, 1790) is a globally
threatened species (Birdlife International 2021), coming under the family Threskiornithidae of the order Pelecaniformes.
This wading bird is also called the Indian White Ibis, Black-headed Ibis or
Black-necked Ibis. It is a widespread resident species across the Indian
subcontinent, known to breed in India, Sri Lanka, Nepal, and Myanmar (Ali &
Ripley 1968; Hancock et al. 2001; Grimmet et al.
2011). In the recent past, the population of the species has declined and
continues so worldwide due to various anthropogenic reasons. The species is
listed in the Near Threatened category of the IUCN Red List (Birdlife
International 2021). In Kerala, the bird species was rare until the mid-1990s
and now has become a regular in most of the wetlands (Sashikumar
et al. 2011). Meanwhile, scientific information on the population and ecology
of this near-threatened species is scanty except for a few reports. The present
study is the first breeding record reported from the Malappuram district of Kerala
state.
In Kerala, the first breeding record of the
species was reported from Wayanad district (Balakrishnan & Thomas 2004);
the area is well-known as Panamaram heronry. The
second breeding report came from Kottayam district (Kumarakom)
(Narayanan et al. 2006), which recorded a good breeding population. A recently
small breeding population was noted at Palakkad district (Roshnath
et al. 2017), Thiruvananthapuram Zoo (Bindya et al.
2019), and from Mavoor wetland, Kozhikode district (Shifa 2021).
Thirunavaya wetland (11.001N, 75.991E), is situated in the Malappuram district of
Kerala state. The wetland is mainly an uncultivated paddy field and it is very
close to the northern bank of the Bharathapuzha
River, one of the largest rivers in Kerala. It spreads over nearly 150 ha
bifurcated into two halves by the railway track. The wetland is also known for
the cultivation of lotus flowers. One side of the wetland is modified into
human habitation. The wetland is flooded during the south-west monsoon
(June–September). During other seasons the wetland is extremely marshy. A small
canal flows through the area. The margin of the canal is covered with a large
number of screw pines (Pandanus sp.) which are also utilized by
Openbill Stork for nesting. Being a breeding ground for Oriental White Ibis,
Openbill Stork, and the ‘Near Threatened’ Oriental Darter, the wetland also
acts as potential foraging habitat for a variety of water birds including
Little Cormorant, Little Egret, Intermediate Egret, Common Kingfisher, Pied
Kingfisher, Purple Heron, Pond Heron, Grey Heron, and other wetland associated
avifauna.
Generally, the breeding period of Oriental
White Ibis is in the monsoon season from June to September (Arif
& Basheer 2012; Shifa 2021); the late breeders
extend their breeding period from September to April (Narayanan et al. 2006).
The nesting of Oriental White Ibis was noticed in October 2021 during a bird
survey in Thirunavaya Wetland. The breeding plumage
of the adult ibises and the begging behaviour of
fledglings for food are very unique features to detect them as an active
breeding colony. At the first observation itself all nestlings grew up into fledglings.
Overall, eight nests were observed during the surveys. Out of which four were
of Oriental White Ibis, three were of Openbill Stork, and one of Oriental
Darter nest. The breeding site was observed weekly for three months from
October to December. For observation Nikon binoculars (10 x 40) were used.
Photographs were taken by the Nikon P1000 model. The tree species used for
colonial nesting is Barringtonia acutangula. The height of the nest tree is 4m from the
wetland. The water level is < 0.5m and covered by the invasive species Salvinia molesta.
The GBH of the nest tree is 0.84 m and the width of canopy coverage is 1.69 m.
The nests are made up of locally available twigs and grasses. The availability
of food and low predation risk, as well as reduced anthropogenic stress, maybe
the reasons for the selection of this breeding site.
The
average height of the nesting tree species at Kumarakom
wetlands, Kottayam district was 02.59 ±0.66 m from the water level (Narayanan
et al. 2006), and in Panamaram, Wayanad district was
7±0.45 m (Balakrishnan & Thomas 2004); in Thiruvananthapuram Zoo the nest
height is 6 m from the ground (Bindya et al. 2019),
whereas in Palakkad district it is 5 m (Roshnath et
al. 2017). The studies in Calicut district (Shifa
2021), did not measure the exact nest height. The present study shows certain
deviations from the results of the above records. In Thirunavaya
wetlands Oriental White Ibis used an average nest height of 3.18±0.49 m. The
wetland heronry is a communal breed site that bears an association of two
species, Openbill Stork and Oriental Darter. Ibises bears a population count of
eight adult parents and nine fledglings. Among Openbill Storks six adult
parents and five young ones occur, whereas among Oriental Darter two adult
parents and two young ones occur.
The Thirunavaya wetland is a feeding and breeding ground for a
large number of avifauna including near-threatened species like Oriental White
Ibis, Painted Stork, Oriental Darter, and Wooly Necked Stork; moreover, it is
an abode for thousands of migratory birds. The spoting
of large colonial nesting of Asain Openbill Stork is
also witnessed the importance of this
fragile ecosystem. Around
120 nests were counted by the survey conducted by Re Echo, an environmental
organization in Thirunavaya. The proposed Silverline
Railway Project is passing through this wetland, which will probably lead to an
ecological disaster for the wetland in the future.
Table 1. Breeding of waterbird species in Thirunavaya
heronry during October–December 2021.
|
Species |
Total no.
of nests |
Total no.
of fledglings |
Nesting success |
|
Oriental White Ibis |
4 |
9 |
Success |
|
Oriental Darter |
1 |
2 |
Success |
|
Openbill stork |
3 |
5 |
Success |
*Nesting success:
nest with at least one fledgling (Mayfield 1975).
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