Bridled Tern

Scientific Name: Onychoprion anaethetus

Malay Name: Camar Batu Biasa

Chinese Name: 褐翅燕鸥

Range: Found along the coasts and offshore islands of Africa to Indian Ocean, Arabian Peninsula, southern China, Southeast Asia, Australia, Central and South America

Taxonomy: Polytypic. Subspecies are: melanopterus, antarcticus, anaethetus, nelsoni.

Local Subspecies: anaethetus

Size: 37-42 cm

Identification: Non-breeding adult has dark brownish-grey upper side, thin whitish nuchal band, whitish forehead-patch, blackish crown, nape and mask, deeply forked tail and blackish bill, legs and feet. Breeding adult has clean white forehead and short eyebrow contrast with black eyestripe, crown and nape. Juvenile resembles non-breeding adult but has whitish tips and dark subterminal bars on upperparts and wing-coverts.

Habitat: Open seas.

Behaviour/Ecology: Seldom dives, preferring to pick up food material from the water surface. Feeds in the open seas, rarely coming to coastal waters.

Local Status: Uncommon resident and uncommon migrant

Conservation Status: Least Concern (BirdLife International 2019)

Location: Straits of Singapore.

Migrant bar chart (see more bar charts):

Bridled Tern Onychoprion anaethetus
Estimated average number of individuals by week based on eBird data, Jul 2013 to Jun 2023
Peak week Sep 17-Sep 23
Early date 24 Jul 1994
Late date 28 Jun 2014
Recorded both as a migrant and a resident; migrates through the Singapore Strait in fall and spring. Peaks on the bar chart may be affected by the frequency of pelagic trips at different times of the year.


BirdLife International. (2019). Onychoprion anaethetus. The IUCN Red List of Threatened Species 2019. Accessed on 1 January 2023

Jeyarajasingam, A., & Pearson, A. (2012). A Field Guide to the Birds of Peninsular Malaysia and Singapore. Oxford University Press.

Robson, C. (2014). Field guide to the birds of South-East Asia (Second Edition). Bloomsbury Publishing, London.

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