Masked Booby (Sula dactylatra)

Everything you wanted to know about the Masked Booby (Sula dactylatra)

Masked booby Sula dactylatra

Masked booby (Sula dactylatra)

The Masked booby (Sula dactylatra) is a huge, white tropical seabird that resembles a gannet, which has a black-colored tail with aerofoil or trailing edges, and furthermore, this bird has a yellow-colored bill as well. However, the darker facial epidermis that surrounds the eyes and bill of this bird looks like a mask, and this is one of the main reasons that this species got its name. Moreover, the masked boobies are discovered across the open ocean in tropical and subtropical regions as they hunt while plunge diving, which makes them often known as “pursuit divers.”

These birds generally choose nesting areas near the shore, so they can be seen around those shores. However, some of the birds of this species stay closer to the breeding and nesting areas in order to safeguard them throughout the whole year. Therefore, most of the tropical marine islands, which are located all around the world, are under these masked boobies’ breeding regions.


It is a huge seabird that belongs to the booby and gannet families, which are known as Sulidae. The masked boobies are also known as the masked gannet or the blue-faced booby. Furthermore, the masked booby( Sula dactylatra) was first discovered by the French scientist René-Primevère Lesson in 1831, and it is one of six species in the genus Sula of boobies.

  • Red-footed booby (Sula sula)
  • Brown booby (Sula leucogaster)
  • Nazca booby (Sula granti)
  • Blue-footed booby (Sula nebouxii)
  • Peruvian booby (Sula variegata)

Scientific classification

Binomial name:Sula dactylatra

Statistical details about Masked booby bird:

About how many birds are there at present?

There are probably less than (about) 2000 individuals in the world.

How long can they live?

Its life span is around 16 years and 03 months.

What is the average weight of a Masked booby bird?

The average weight of a Masked booby is 1220-2353 g.

What is the average length of a Masked booby bird?

The average length of a Masked booby is approximately 74-86 cm.

What is its average wingspan size?

The wingspan size is around 152 cm.

What is its average upper elevation limit?

No data.

What is its average lower elevation limit?

No data.

Habits and lifestyle

Most of the time, the masked boobies feed alone in couples or in small groups at sea over deep water, and they usually travel great distances from nesting colonies for hunting. Additionally, masked boobies are known as “Pursuit Divers” as they dive deep to hunt their prey. Sometimes they may be able to catch flying fish while flying and can also make short dives. Moreover, the masked boobies may have a variety of aggressive and regional behaviors on land. These include fluttering and flapping wings and stabbing or jabbing to fend off intruders at the nesting area, as well as showing-off by bending forward and holding out its beak to show its nesting location to the other visiting birds.

These birds may use sky-pointing on two occasions, such as as a sign of taking-off or when mating. In brief, the mating behaviors between these birds mainly involve bill clashing between partners in regimented mutual jabbing, parading (usually by the male), insistent staring, and symbolic nest building.

The Masked Boobies make a landing cry during the approaching of nest areas, and occasionally, they make high-frequency calls prior to their hunting or plunge-diving. Although the birds are particularly noisy during chippy and mating behaviors, which are visible at their colonies.

What do they feed off?

Masked boobies eat flying fish, cephalopods, blue flying fish, mirror wing flying fish , sailfin flying fish, glider flying fish, and Atlantic flying fish; other fish such as yellow-tailed amber jack, skip jack tuna, mackerel scad, pompano dolphin fish, mahi-mahi, brown chub, red-barred hawk fish, snake mackerel, frigate tuna, Pacific saury, ribbon half beak, flat needle fish, and mullet of the genus Mugil, and purple-back flying squid.

What are their birthing rituals?

Most often, masked boobies mate in isolated colonies with extremely few nests per square meter. Therefore, the relationship between the two is monogamous, and the mates may frequently continue in multiple seasons. Nevertheless, the partners frequently use the same nesting area for a number of years as protection for their breeding region. Both partners take their turns in incubating, brooding, and raising the chicks or hatchlings. In addition, the eggs are incubated under the webs under their feet. Afterwards, within the first few days of hatching, the first chick often throws its sibling out of the nest. However, in a rare instance, both chicks are observed to live for several weeks. Additionally, up until around 4–8 weeks after fledging, the chick is brooded for the first 3–4 weeks and fed by both parents through imperfect regurgitation.

How do you identify them?

In fact, the masked booby is a huge, white tropical seabird that resembles a gannet. It also has a black tail, a straight and serrated long yellow beak, and black trailing edges on its wings. Therefore, an adult masked booby looks similar to a little gannet without the yellow head markings. The tail feathers are long and wedge-shaped, while the body, wings, and neck are all long and angular. Except for the black flight feathers on the whole trailing edge of each wing and the black tail feathers, its plumage is entirely white (nonetheless, the middle tail feathers can be white). Additionally, individuals’ feet can range in color from greyish-green to olive to yellow.

As mentioned earlier, this species was named after its mask-like, dark grey-blue, pitch-black face skin. In contrast, the Tasman booby differs from other subspecies because of its lengthy and huge wings and a dark brown iris, whereas the other masked booby subspecies have yellow irises.

Where can you see them?

This species is broadly discovered in the tropical seas, excluding the eastern Atlantic Ocean, the northern Indian Ocean (for example, Sri Lanka), and the central-eastern Pacific Ocean.

Do they have any natural predators?

The International Union for Conservation of Nature (IUCN) has categorized and classified the Masked booby (Sula dactylatra) under “Decreasing” species because it is believed that the slow and yet considerable decreases are happening due to the removal of eggs. However, the adult birds also get killed because of hunting at the breeding colonies.

In conclusion, the Masked Boobies are sensitive to human disturbance, and they may abandon their nests when people come within 10 to 20 meters of them. But yet, the population is not highly affected by this. Nevertheless, the main predators or threats in certain areas of the booby’s range are invasive animals, notably house rats and feral cats, which pose a hazard.

Population Trend-Decreasing
Population status-Least concern (LC)-10 August 2018



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