Brown Noddy vs Sooty Tern

In short

The Brown Noddy (Anous stolidus) and Sooty Tern (Onychoprion fuscatus) can be distinguished primarily by plumage and behavior. The Brown Noddy is uniformly brown with a whitish cap, while the Sooty Tern is black above and white below. Behaviorally, the Sooty Tern is almost always airborne, whereas the Brown Noddy is more likely to be seen resting on land.

Identification tips

• Plumage: Look for the Brown Noddy's uniform brown color with a whitish cap versus the Sooty Tern's black and white contrast.
• Behavior: Observe whether the bird is frequently airborne (Sooty Tern) or resting on land (Brown Noddy).
• Habitat: Consider the nesting location; Brown Noddies prefer vegetated islands, while Sooty Terns favor open sandy areas.

Size

Both species are similar in size, but the Brown Noddy appears slightly bulkier due to its more robust body structure.

Plumage

The Brown Noddy is entirely brown with a whitish cap, giving it a more uniform appearance. In contrast, the Sooty Tern has a striking black upper body and white underparts, with a sharp demarcation between the two.

Behaviour

The Sooty Tern is known for its almost constant flight, rarely coming to land outside the breeding season. The Brown Noddy, however, often rests on land or on structures like buoys.

Habitat

Both species nest on remote islands, but the Brown Noddy is more likely to be found on islands with sparse vegetation, while the Sooty Tern prefers open sandy areas.

Voice

Vocalizations are not a primary distinguishing feature in the field, as both species have similar calls.