Nazca Booby: The Largest of the Galapagos Boobies

The nazca booby is the largest of the three Galapagos boobies — bright white with a black mask and a sharp orange bill. It is best known for a dark habit called siblicide, where the first chick to hatch pushes its sibling out of the nest. Here is what it is, that brutal nesting story, and where to see it. The Galapagos Conservation Trust puts the population at around 20,000 breeding pairs, making the largest booby in the islands a common sight.

Next to the comic blue-footed booby, the nazca booby looks almost elegant — crisp white feathers, a neat black mask, a dagger of a bill. And then a guide tells you what happens in the nest, and the elegant bird suddenly seems a lot more ruthless. It is one stop on the wider Galapagos birds trail, alongside the blue-footed and red-footed booby.

What is the Nazca booby?

The nazca booby (Sula granti) is a large white seabird and the biggest of the three booby species in the Galapagos. You will know it by its bright white body, black wing-tips and tail, a dark face mask and a long orange-yellow bill. For a long time it was lumped in with the masked booby, and was only recognised as a separate species in 2002. For the rest of the archipelago’s fauna, see our Galapagos wildlife guide. Planning a trip around what you want to see? Tell us your dates and we’ll send a free quote within 24 hours.

Unlike its blue-footed and red-footed cousins, the galapagos nazca booby has plain greyish feet — the colour is in the face, not the toes. There are roughly 15,000 to 20,000 breeding pairs in the islands, so on the right island they are easy to find.

Nazca Booby vs Masked Booby: Why It Got a New Name

The number-one question I get about this bird: what is the nazca booby vs masked booby difference? They look almost identical, and for a long time scientists agreed — the nazca booby was considered a subspecies of the masked booby until a 2002 molecular study split them into separate species (Sula granti). The easiest field tell is the bill: the nazca’s is orange-pink, the masked booby’s is yellow. The name comes from the Nazca tectonic plate beneath the eastern Pacific, the bird’s home range. So when an old guidebook calls it a ‘masked booby’, it is not wrong — just out of date. The name points to the Nazca Plate itself, the slab of ocean floor beneath the eastern Pacific.

Nazca booby siblicide: the brutal nest

The nazca booby siblicide is one of the most talked-about behaviours in the islands. A female lays two eggs a few days apart, but the first chick to hatch almost always pushes the second egg or chick out of the nest, leaving just one to be raised.

It looks merciless, but it is a reliable insurance policy: the second egg is a backup in case the first fails, and raising a single strong chick gives the best odds in a tough environment. Watching it is sobering — and a vivid reminder that the Galapagos is wild, not a zoo.

Nazca Booby Galapagos: Where to See It

The nazca booby nests in big ground colonies on a few islands, so once you are in the right spot they are unmissable:

• Española (Punta Suárez) — nazca boobies share the trail with blue-footed boobies and the waved albatross.
• Genovesa (Tower Island), Darwin Bay — huge seabird colonies, reached on cruises.
• Tip: Española is the one spot where you can realistically tick off all three Galapagos boobies in a single walk.

See how it compares to its cousins in my guides to the blue-footed booby and the red-footed booby. Want to see this for yourself? Our 10-day complete Galápagos tour gets you there with a naturalist guide.

Quick Nazca booby facts

A few nazca booby facts worth knowing:

• Species: Sula granti — the largest of the three Galapagos boobies.
• It was split from the masked booby and recognised as its own species in 2002.
• It practises obligate siblicide: two eggs are laid but only one chick is raised.
• The Galapagos holds around 15,000 to 20,000 breeding pairs.
• It nests on the bare ground in colonies, unlike the tree-nesting red-footed booby.

A diver built for impact

Watch a feeding flock and you understand the body at once. From ten or twenty metres up it folds its wings and drops like a thrown spear, hitting the water at speed to stab fish well below the surface. To survive that repeated impact it is built like a missile — a long, tapered body, a sharply pointed bill, and air sacs under the skin of the face and chest that cushion the blow. Its nostrils are permanently sealed shut, so the sea cannot be forced into them on the dive; it simply breathes through the corners of its mouth instead. That technique is called plunge diving: it folds its wings and hits the water like a dart, sometimes from 30 metres up.

That dramatic technique is all about reaching prey other seabirds cannot. It feeds mainly on small schooling fish and squid, often well offshore, and will travel long distances on a single foraging trip — ranging tens of kilometres out to sea and staying out for hours before returning to feed a waiting chick. When sardines or flying fish are abundant the diving turns spectacular, with dozens of birds raining into a single bait ball in a few frantic minutes.

From downy chick to masked adult

Adults are unmistakable — clean white bodies, dark flight feathers, a black facial mask and a bill that ranges from pink to soft orange. Youngsters look nothing like them. Fresh from the egg they are blind and naked, then grow a coat of white down; as they mature they pass through a mottled brown-and-white stage, with a dark hood and collar, that can puzzle first-time visitors before the crisp adult plumage finally comes in. Reaching that full, polished look can take a couple of years.

On land the colonies are remarkably safe. There are few natural enemies on the open, predator-free headlands they favour, which is exactly why such ground-nesting seabirds thrive here. The real dangers come from the sea and the sky: frigatebirds harass returning adults to rob them of their catch, the occasional hawk or gull snatches an unguarded egg or chick, and a shift in ocean temperature during an El Niño can empty the water of fish and wipe out a whole season of breeding in one stroke.

The nest itself holds one of the harshest stories in the bird world. A pair usually lays two eggs a few days apart, yet they almost never raise two chicks. The first to hatch typically shoves its younger sibling out of the shallow scrape to die — an inbuilt behaviour, not a mere accident of hunger. The second egg is essentially insurance: if the first fails to hatch, or the first chick dies young, the spare gives the parents a second chance at raising one strong fledgling.

Life in the colony runs to a slow, social rhythm. Pairs return to the same patch of open ground year after year, greeting each other with bill-pointing and sky-pointing displays, and both parents share the long work of incubating and feeding the single surviving chick. That youngster leans on them for months, growing fat on regurgitated fish before it finally takes to the wing — and even then it may linger near the colony, still begging, well after it can fly. It is a heavy investment in one chick, repeated patiently season after season.

It is also only one of three members of its family on the islands. Alongside it patrol the comic blue-footed booby, famous for its turquoise feet and high-stepping dance, and the tree-nesting red-footed booby, smallest of the trio. Catching all three on a single island-hopping route — each with its own feet, nesting style and personality — is one of the quieter pleasures of a Galápagos trip.

Telling the Three Boobies Apart, and Where Each One Is

The Nazca booby is the largest of the three and the one people most often misidentify. Side by side the differences are obvious: the blue-footed booby is the smaller, brown-backed bird with the famous feet, and the red-footed booby is smaller again and the only one of the three that nests in trees rather than on bare ground.

Location sorts them almost as well as plumage does. Nazca colonies are on Espanola Island and Genovesa Island, which is also where you find the swallow-tailed gull and the red-billed tropicbird on the same cliffs. For the full seabird picture, see our Galapagos birds guide.

Frequently asked questions about the Nazca booby

Seeing the Nazca booby up close

The nazca booby is the booby that makes you think. Beautiful from a distance, ruthless in the nest, and a perfect example of how the Galapagos rewards a curious traveller with stories you will retell for years.

Read more at the Galapagos Conservation Trust and Wikipedia, or meet the rest of the cast in my guide to Galapagos islands animals.