Wildlife Clinic

Species

Bridled tern

Onychoprion anaethetus

A grey-backed tropical tern of the Gulf Stream, seen off Georgia's coast in summer.

A bridled tern standing on a stone ledge above turquoise water, its dark back, black cap and white eyebrow stripe crisp.

Photo ian bullock (opens in a new tab) / iNaturalist, CC BY 4.0 (opens in a new tab)

At a glance

Size
About 30 to 32 cm long
Weight
About 95 to 150 g
Habitat
Warm offshore waters, often near floating sargassum weed
Diet
Small fish and squid
In Georgia
Offshore in summer; occasionally blown ashore by storms
Voice
A yapping "wep-wep"
Rabies vector
No

Identification

Key marks
Grey-brown back; black cap; white forehead that extends behind the eye; white collar
Told apart from
Sooty tern, which is black above and lacks the pale collar
Where to look
Far offshore in summer, often perched on floating debris

Behaviour

Bridled terns feed on small fish around floating sargassum mats and often rest on flotsam.

Why they matter

These terns depend on the floating sargassum of the Gulf Stream, a moving habitat that shelters young fish and turtles. They show how much of the ocean's life gathers around such floating islands.

Reproduction and lifecycle

Nest — A scrape among rocks on tropical islands
Eggs — Usually one
Incubation — About 28 to 30 days
Chick — Fed by both parents
Lifespan — Several years

Living around people

  • A bridled tern ashore after a storm needs a rehabilitator.

Misconceptions

  • Terns are small gulls. They are a separate group, with pointed bills, and most dive for fish.

Related species

Seasonal activity

When this species is breeding, and when there are nests on the ground. Mowing during the shaded months is how most nests are found.

Breeding and active nests by month for this species
JanFebMarAprMayJunJulAugSepOctNovDec
BreedingJan: noFeb: noMar: noApr: noMay: noJun: noJul: noAug: noSep: noOct: noNov: noDec: no
Active nestsJan: noFeb: noMar: noApr: noMay: noJun: noJul: noAug: noSep: noOct: noNov: noDec: no
NotesAt sea in the tropicsAt seaAt seaNesting on Caribbean islandsNestingOffshoreOffshoreOffshore; storms may blow birds ashoreOffshoreLeavingAt seaAt sea

Where it lives

Recorded in 21 states and provinces. Each one links to the other animals there, and to the rehabilitators licensed for them.

If you found one

Answer a few questions and you will get a specific answer for what you are looking at.

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