Masked Booby vs Nazca Booby

In short

The Masked Booby and Nazca Booby are similar seabirds, but the most reliable field mark is the bill color: Masked Boobies have a yellow bill, while Nazca Boobies have an orange bill. Both species are large, white boobies with black on their wings and tail, making bill color a key distinguishing feature.

Identification tips

• Bill color: Masked Booby has a yellow bill, Nazca Booby has an orange bill.
• Facial mask: More pronounced in Masked Booby, but can be subtle.
• Location: Consider geographic range if known, as Nazca Boobies are primarily found in the eastern Pacific, particularly around the Galápagos Islands.

Size

Both species are similar in size, being large seabirds, with no significant size difference noted in the field.

Plumage

Both species have predominantly white plumage with black on the wings and tail. The Masked Booby's facial mask is more pronounced, but this can be subtle and variable.

Behaviour

Both species exhibit similar pelagic behaviors, often seen plunge-diving for fish. They are also known for their nesting habits, which involve laying two eggs but typically raising only one chick.

Habitat

Both species inhabit tropical and subtropical oceanic islands and are often found in similar marine environments.

Voice

Vocalizations are not a primary distinguishing feature in the field, as both species have similar calls and are generally silent when not at colonies.