The Sooty Tern (Onychoprion fuscatus) is an Australian bird or regular visitor that can be identified most reliably by combining shape, plumage, habitat and behaviour. A striking black-and-white tern with very dark upperparts, white forehead and underparts, long pointed wings and a deeply forked tail. Adults are typically about 33–36 cm long, although posture, sex, age and plumage can affect how large an individual appears in the field.
How to identify a Sooty Tern
A striking black-and-white tern with very dark upperparts, white forehead and underparts, long pointed wings and a deeply forked tail. Start with overall silhouette before focusing on colour. Check the bill, legs, tail, wing shape and any bold head or body pattern. Distance, shade, glare and strong Australian sunlight can change the apparent colour of feathers, so several matching features are more useful than a single mark.
Sooty Terns are extremely aerial and may remain at sea for long periods. Huge colonies can be intensely noisy when birds return to breeding islands. Behaviour can be one of the quickest ways to confirm an identification because closely related birds often feed, fly or perch differently even when their plumage looks similar.
Where is the Sooty Tern found in Australia?
A highly oceanic tropical seabird around northern Australian waters, breeding on remote islands and coral cays including Great Barrier Reef sites.
Typical habitat includes open tropical ocean, coral cays, offshore islands and waters around productive reef systems. Distribution can shift with rainfall, drought, breeding conditions, migration, tides and local food supply, so an apparently unusual sighting should be checked against season as well as location.
What does the Sooty Tern eat?
Small fish, squid and other marine prey taken near the surface, often in association with predatory fish or other seabirds. Watching exactly how a bird feeds can provide another useful clue. Note whether it runs and pecks, probes mud, sweeps its bill, plunge-dives, surface-dips or catches food in flight. Feeding technique often separates species that share the same habitat.
Wild birds do not need processed human food. Protecting natural habitat, clean water and native food sources is usually a better way to support them than regular feeding.
Behaviour and calls
Sooty Terns are extremely aerial and may remain at sea for long periods. Huge colonies can be intensely noisy when birds return to breeding islands.
The voice is loud, harsh and repetitive, with distinctive calls that carry over crowded colonies. Voice can be especially useful when distance, a crowded flock or low light makes visual identification difficult. Try to notice the rhythm and tone as well as a written approximation of the sound.
Nesting and breeding
They breed in dense colonies on remote tropical islands, placing eggs on open ground or in sparse vegetation. Breeding timing varies according to latitude, climate and species. Many migratory shorebirds seen in Australia breed in the Northern Hemisphere, while resident terns and seabirds may nest on Australian beaches or offshore islands. If you find a nest or dependent young, observe from a respectful distance.
Similar birds
Bridled Terns have greyer upperparts and a broader white eyebrow, while Black Noddies have shorter tails and a pale cap rather than a white forehead.
When two species remain difficult to separate, compare photographs against multiple field marks rather than choosing on colour alone. Geographic range, voice, habitat and feeding style may be more decisive than one feather pattern.
Quick identification tip
Remember three things: its approximate size is 33–36 cm; its key visual clue is a striking black-and-white tern with very dark upperparts, white forehead and underparts, long pointed wings and a deeply forked tail.; and a typical setting is open tropical ocean, coral cays, offshore islands and waters around productive reef systems. Matching all three gives a much stronger identification than any one clue by itself.
Sources and further reading
For additional Australian bird information and conservation guidance, see BirdLife Australia bird profiles and the Australian Museum bird collection. Image licensing and creator information for this page is recorded from the linked Wikimedia Commons file page.
