Journal of Threatened Taxa | www.threatenedtaxa.org | 26 August 2026 | 18(8): 29552–29554

ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print)

https://doi.org/10.11609/jott.10690.18.8.29552-29554

#10690 | Received 26 May 2026 | Final received 04 July 2026| Finally accepted 31 July 2026

Breeding tern colonies in Valinokkam Lagoon, Tamil Nadu, India: additional records from the Gulf of Mannar region

H. Maitreyi ¹ , H. Byju ² , N. Raveendran ³ & S. Ravichandran ⁴

^1,2,4 Centre of Advanced Study in Marine Biology, Annamalai University, Parangipettai, Tamil Nadu 608502, India.

³ Iragukal Amritha Nature Trust, 61, Ramachandra Thadaga Street, Thirumangalam, Madurai, Tamil Nadu 625706, India.

¹ maithgd@gmail.com, ² byjuhi@gmail.com (corresponding author), ³ iantravee@gmail.com, ⁴ sravicas@gmail.com

Editor: Bhargavi Srinivasulu, Zoo Outreach Organisation, Hyderabad, India. Date of publication: 26 August 2026 (online & print)

Citation: Maitreyi, H., H. Byju, N. Raveendran & S. Ravichandran (2026). Breeding tern colonies in Valinokkam Lagoon, Tamil Nadu, India: additional records from the Gulf of Mannar region. Journal of Threatened Taxa 18(8): 29552–29554. https://doi.org/10.11609/jott.10690.18.8.29552-29554

Copyright: © Maitreyi et al. 2026. 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.

Terns (family Laridae) comprise 43 globally distributed species (AviList Core Team 2025), of which 18 are recorded in India, and nine breed along Indian coasts and sandbars (Byju et al. 2025a). Historical breeding records of Little Tern Sternula albifrons from Rameswaram by Abdulali (1942) lack evidence. Subsequent breeding records in India are from Chilika, Odisha (Balachandran et al. 2005; Li et al. 2009) and Kodiyakkarai, Tamil Nadu (Holloway 1993). More recently, breeding colonies of Little Tern and Saunders’s Tern Sternula saundersi have been reported on the sandbars of Adam’s Bridge along the Indian coast (Byju et al. 2025a). The present note extends these breeding records to the coastal lagoons of the Gulf of Mannar region of Tamil Nadu by providing the first documentation of breeding colonies of both species from Valinokkam Lagoon.

Valinokkam Lagoon (9.1661^o N, 78.6141^o E), is a man-made coastal lagoon bordered by state-operated saltpans, covering approximately 1,146 ha and extending over 10.12 km. Extensive mudflats and shallow saline habitats are created by periodic seawater pumping and evaporation for salt production. Byju et al. (2023; 2025b) have conducted ornithological studies earlier at this site.

Breeding populations of both terns (April–May 2026) were observed as part of a long-term coastal bird monitoring program at Valinokkam Lagoon. The colony size was estimated through total counts of active nests and direct observations of incubating adults and associated breeding activity within nesting areas (Image 1).

A total of 30 active nests of Little Tern was recorded from two colonies comprising 12 and 18 nests, respectively, on open sand flats. Nests consisted of shallow, moist scrapes lined with fragmented shell material and lacked surrounding vegetation, consistent with earlier observations from arid coastal habitats (Panagoda et al. 2020; AlRashidi 2025). Clutch size varied from one to three eggs (Cheah & Ng 2008), although two-egg clutches dominated. Eggs were olive-green with prominent brown blotches (Image 2). Egg laying was observed during the first week of April, and chicks were recorded during the first week of May. Four nests contained two chicks each, while one nest contained both an egg and a chick, indicating asynchronous hatching. Most nests were located within 30 m of nearby water sources.

Breeding behaviour included aerial displays, chasing flights, and one partner carrying fish to the incubating partner. Biparental incubation was observed throughout the nesting period. Incubating adults frequently wet their ventral plumage by dipping into the nearby water, presumably as a thermoregulatory adaptation to hot ambient temperatures (AlRashidi 2025). One nest contained a damaged egg, although the cause could not be determined.

Eight nests of Saunders’s Tern (four each in two colonies) were documented on elevated mud bunds within active saltpan areas. Nests were shallow, moist scrapes containing fragmented shell material. All nests had a single egg. Eggs were paler and sandier in colouration, with smaller brown speckles compared to those of Little Tern (Image 3). Nests were situated only a few metres from water and lacked vegetation cover. Both adults participated in incubation, and courtship feeding behaviour was similar to that observed in Little Terns.

The occurrence of breeding colonies of both sympatric tern species within the saltpan-associated landscape highlights the importance of Valinokkam Lagoon as a potential breeding habitat for small coastal terns. Breeding habitats at the lagoon are particularly vulnerable to increasing human disturbance, including fishing, livestock grazing, and vehicular movement. Long-term monitoring and protection of the wetland are crucial for conservation of breeding populations.

For images - - click here for full PDF

References

Abdulali, H. (1942). The distribution of the Rosy Tern. Journal of the Bombay Natural History Society 43: 104.

AlRashidi, M. (2025). Breeding ecology and incubation behaviours of Little Tern Sternula albifrons in the Sabkhat Al-Fasl Lagoons, Saudi Arabia. Marine Ornithology 53(2): 235–241. https://doi.org/10.5038/2074-1235.53.2.1642

AviList Core Team (2025). AviList: The Global Avian Checklist, v2025. https://doi.org/10.2173/avilist.v2025. Accessed on 7.vii.2026.

Balachandran, S. et al. (2005). Habitat evaluation of Chilika Lake with special reference to birds as bioindicators. Final Report (2001–2005), Bombay Natural History Society, Mumbai. 141 pp.

Byju, H. et al. (2023). Importance of conserving a critical wintering ground for shorebirds in the Valinokkam Lagoon—a first study of the avifaunal distribution of the southeastern coast of India. Journal of Threatened Taxa 15(8): 23696–23709. https://doi.org/10.11609/jott.8494.15.8.23696-23709

Byju, H. et al. (2025a). Breeding tern colonies on the sandbars of Adam’s Bridge, India: new records and significance. Journal of Threatened Taxa 17(3): 26680–26689. https://doi.org/10.11609/jott.9591.17.3.26680-26689

Byju, H. et al. (2025b). Temporal dynamics of shorebird assemblages in Valinokkam Lagoon, southeast India: a new wintering site along the Central Asian Flyway. Ornis Hungarica 33(2): 22–42. http://doi.org/10.2478/orhu-2025-0018

Cheah, J.W.K. & A. Ng (2008). Breeding ecology of the little tern, Sterna albifrons Pallas, 1764 in singapore. Nature in Singapore 1: 69–73.

Holloway, M. (1993). The variable breeding success of the Little Tern Sterna albifrons in south east India and protective measures needed for its conservation. Biological Conservation 65: 1–8. https://doi.org/10.1016/0006-3207(93)90189-8

Li, Z.W.D. et al. (2009). Status of Waterbirds in Asia—Results of the Asian Waterbird Census: 1987–2007. Wetlands International, Kuala Lumpur, 35 pp.

Panagoda, B.G. et al. (2020). Sympatric breeding of two endangered Sternula terns, Saunders’s S. saundersi and Little S. albifrons Terns, in the Rama’s Bridge of Sri Lanka. BirdingAsia 34: 76–83.