Brown Booby vs Nazca Booby

In short

The Brown Booby and Nazca Booby are both large seabirds with distinct plumage differences. The Brown Booby has a dark brown head and upperparts with a contrasting white belly, while the Nazca Booby is mostly white with a black tail and wingtips. Both species have similar body shapes but differ in bill color and facial markings.

Identification tips

• Bill Color: Brown Booby has a yellowish bill, while Nazca Booby has an orange or pinkish bill.
• Facial Markings: Look for the black mask around the eyes in Nazca Booby.
• Plumage: Note the dark brown upperparts of the Brown Booby versus the mostly white plumage of the Nazca Booby.
• Location: Consider the geographic range; Nazca Boobies are more restricted to the eastern Pacific.

Size

Both species are similar in size, but the Nazca Booby is slightly larger and more robust.

Plumage

The Brown Booby has a dark brown head, neck, and upperparts with a white belly and underwing coverts. In contrast, the Nazca Booby is predominantly white with black wingtips and tail, and a distinctive black mask around the eyes.

Behaviour

Both species are plunge divers but the Brown Booby often engages in more horizontal dives. They share similar feeding behaviors, targeting fish near the water's surface.

Habitat

Both species prefer nesting in areas with minimal human disturbance. The Brown Booby is more likely to be found on cliff edges or sandy atolls, while the Nazca Booby typically nests on flat ground on islands.

Voice

Vocalizations are not a primary distinguishing feature between these species in the field.