Bridled tern

Bridled tern
Adult on Lady Elliot Island, Australia
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Charadriiformes
Family: Laridae
Genus: Onychoprion
Species:
O. anaethetus
Binomial name
Onychoprion anaethetus
(Scopoli, 1786)
Synonyms

Sterna anaethetus Scopoli, 1786

Onychoprion anaethetus - MHNT

The bridled tern (Onychoprion anaethetus)[2][3][4] is a seabird of the family Laridae. It is a bird of the tropical oceans. The scientific name is from Ancient Greek. The genus comes from onux meaning "claw" or "nail", and prion, meaning "saw". The specific anaethetus means "senseless, stupid".[5]

Description

This is a medium-sized tern, at 30–32 cm in length and with a 77–81 cm wingspan similar to the common tern in size, but more heavily built. The wings and deeply forked tail are long, and it has dark grey upperparts and white underparts. The forehead and eyebrows are white, as is a striking collar on the hindneck. It has black legs and bill. Juvenile bridled terns are scaly grey above and pale below.

This species is unlikely to be confused with any tern apart from the similarly dark-backed sooty tern and the spectacled tern from the Tropical Pacific. It is paler-backed than that sooty, (but not as pale as the grey-backed) and has a narrower white forehead and a pale neck collar.

Distribution and movements

This bird is migratory and dispersive, wintering more widely through the tropical oceans. It has markedly marine habits compared to most terns. The Atlantic subspecies melanopterus breeds in Mexico, the Caribbean and west Africa; other races occur around the Arabian Peninsula and in Southeast Asia and Australasia, but the exact number of valid subspecies is disputed. It is a rare vagrant to western Europe. These are the four subspecies listed by the IOC:

Breeding

This species breeds in colonies on rocky islands. It nests in a ground scrape or hole and lays one egg. It feeds by plunge-diving for fish in marine environments, but will also pick from the surface like the black tern and the gull-billed tern. It usually dives directly, and not from the "stepped-hover" favoured by the Arctic tern. The offering of fish by the male to the female is part of the courtship display.

Lady Elliot Island, Qld, Australia

Various views and plumages

  • In non-breeding plumage
    In non-breeding plumage
  • Bridled tern, at rookery
    Bridled tern, at rookery
  • Juvenile on Lady Elliot Island, Queensland, Australia
    Juvenile on Lady Elliot Island, Queensland, Australia
  • In flight Lady Elliot Island, Queensland, Australia
    In flight Lady Elliot Island, Queensland, Australia
  • Juvenile bathing at Perth Zoo
    Juvenile bathing at Perth Zoo
  • Juvenile or adult with non-breeding plumage taking off from a sea debris perch during Pelagic expedition off coast of Malpe
    Juvenile or adult with non-breeding plumage taking off from a sea debris perch during Pelagic expedition off coast of Malpe
  • O. a. antarcticus after dive (composite)
    O. a. antarcticus after dive (composite)
  • ID composite
    ID composite
  • With egg in nest under boardwalk steps on Penguin Island, Western Australia
    With egg in nest under boardwalk steps on Penguin Island, Western Australia

References

  1. ^ BirdLife International (2019). "Onychoprion anaethetus". IUCN Red List of Threatened Species. 2019: e.T22694730A154676367. doi:10.2305/IUCN.UK.2019-3.RLTS.T22694730A154676367.en. Retrieved 19 November 2021.
  2. ^ Scopoli, Giovanni Antonio (1786). Deliciae florae et faunae Insubricae. Vol. 2. Ticini: Ex Typographia Reg. & Imp. Monasterii S. Salvatoris. Praesidib. Rei litter. permittentibus. p. 92.
  3. ^ Bridge, E. S.; Jones, A. W.; Baker, A. J. (2005). "A phylogenetic framework for the terns (Sternini) inferred from mtDNA sequences: implications for taxonomy and plumage evolution" (PDF). Molecular Phylogenetics and Evolution. 35 (2): 459–469. Bibcode:2005MolPE..35..459B. doi:10.1016/j.ympev.2004.12.010. PMID 15804415. Archived from the original (PDF) on 20 July 2006.
  4. ^ Sometimes the name is (wrongly?) spelled as S. anaestheta, for instance in: Saunders, Howard (1877). "On the Occurrence of the Smaller Sooty Tern at the Mouth of the Thames". The Zoologist. 3. 1: 213–216.
  5. ^ Jobling, James A (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. pp. 46, 282. ISBN 978-1-4081-2501-4.
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