AnimaliaHighest rank in taxonomy. Groups all life into domains: Animalia, Plantae, Fungi, etc.IUCN LCInternational Union for Conservation of Nature — the world authority on species extinction risk, using standardized criteria. — Least Concern — widespread and abundant; not at immediate risk of extinction.In ProgressCurrent stage of this record in the editorial review workflow. Recent Sighting
Sula leucogaster
Brown Booby
Boddaert, 1783
Detailed Texts Multi-lang
A large, aerodynamically built seabird. Adults feature dark brown plumage on the head, neck, back, and wings, which sharply contrasts with a pure white belly and underwing coverts. They have a long, pointed yellow or greenish bill.
Added by
Anonymous Curator
Reviewed by
Under Review
Last modified by
Julia Trouin
TaxonomyBiological classification ranks placing this species within the tree of life, from Kingdom down to Genus.
PhylumRank below Kingdom. Groups organisms sharing a fundamental body plan (e.g., Chordata = vertebrates and some invertebrates).Chordata
ClassRank below Phylum. Subdivides by structural traits (e.g., Mammalia, Aves, Reptilia, Insecta).Aves
OrderRank below Class. Groups related families sharing common ancestry (e.g., Carnivora, Primates).Suliformes
FamilyRank below Order. Groups closely related genera (e.g., Felidae = cats, Canidae = dogs).Sulidae
GenusRank just above Species. The first word in the two-part binomial scientific name.Sula
Taxonomic AuthorityThe scientist who first formally described and published this species, followed by the year of publication.Boddaert, 1783
Record Completeness
96%Coming soon
Ecology & StatusHow this species lives: habitat preferences, diet, behavior, population status, and role in its ecosystem.
OriginWhether the species is native (evolved here), endemic (found only here), or introduced by human activity.
Native
Population TrendDirection of change in population size over time: increasing, stable, decreasing, or unknown.
Decreasing
Breeding SeasonTime of year when this species typically reproduces or flowers.
Year Round
Trophic RolePosition in the food chain: producer, herbivore, carnivore, omnivore, decomposer, or parasite.
Carnivore
Recent SightingsWhether this species has been observed in the wild in Costa Rica within recent years.
Yes
Habitat SummaryOverview of the specific ecosystems and environments where this species is found in Costa Rica. Multi-lang
Pelagic and coastal species inhabiting tropical and subtropical oceanic waters. It nests on isolated rocky islands and coral atolls.BehaviourDaily activity patterns, movement, territory use, foraging style, and seasonal behavioral changes. Multi-lang
They fly with powerful wingbeats interspersed with glides, often very close to the sea surface. They forage at sea but return to land or roost on buoys and vessels during the night.Social ActivitySocial structure: whether the species is solitary, paired, or colonial; hierarchy and communication. Multi-lang
They congregate in very noisy and dense colonies to nest and roost. However, at sea, they tend to hunt solitarily or in small, loose groups.Feeding GuildWhat the species eats, how it forages or hunts, and its role as a consumer in the food web. Multi-lang
Pelagic piscivore. Utilizes plunge-diving from the air at considerable speeds to pierce the surface and catch prey underwater.Trophic Chain DetailsSpecific interactions in local food webs: prey species, predators, competitors, and scavengers. Multi-lang
They are marine predators that frequently follow larger predatory fish (such as tuna) or dolphins, taking advantage as these push schools of small fish and squid to the surface.Reproductive BehaviourMating strategies, courtship displays, nesting or spawning behavior, and parental care. Multi-lang
They nest on the ground, creating shallow depressions adorned with vegetation or stones. They generally lay two eggs, but the chick that hatches first practices obligate siblicide, expelling or killing the younger one, ensuring only one survives.Physical Measures
Length (cm)
64.0 - 75.0 cm
Weight (Grams)
900 g - 1.50 kg
Offspring per cycleTypical number of young (live births, eggs, or seeds) produced by one adult in a single reproductive event or breeding season.1 - 2
Sexual DimorphismObservable physical differences between males and females of the same species (e.g., size, coloration, features).Yes
Lifespan
Sexual MaturityAge at which the individual becomes capable of reproducing for the first time.
2 - 3 Years
Gestation / IncubationDuration from fertilization to birth (mammals) or to hatching (egg-laying species).
42 - 43
Lifespan EstimatedExpected duration of life from birth to natural death under wild conditions.
Males15 - 25 Years
Females15 - 25 Years
Sexual DimorphismPhysical differences in size, coloration, or morphology between males and females of this species.
Males Multi-lang
Slightly smaller and more slender than the female. Its voice is a high-pitched whistle or sigh. The bare facial skin and bill are often a more intense yellow or bright greenish.
Females Multi-lang
Physically larger and heavier. Its vocalization is a harsh honk or quack, resembling that of a goose or duck. The facial skin tends to be paler or a less intense yellowish-green shade.
Evolutionary AdaptationsInherited traits and behaviors that improve the species' survival and reproduction in its specific environment. Multi-lang
Closed nostrils: As an evolutionary adaptation to high-impact diving, they lack external nostrils, which prevents water from rushing in violently when plunging.
Torpedo-shaped body: Their anatomy is exceptionally hydrodynamic, allowing them to swim underwater using their wings and webbed feet to pursue prey.
Main ThreatsDocumented pressures reducing the population: habitat loss, hunting, disease, climate change, and invasive species. Multi-lang
Invasive species: Introduced rats and feral cats on their nesting islands prey heavily on their eggs and chicks.
Interesting FactsSurprising or notable facts that highlight what makes this species unique or ecologically important. Multi-lang
Name origin: Its English name (Booby) and the Spanish nickname (Pájaro bobo) come from the colloquial Spanish word 'bobo' (foolish), due to their lack of fear of humans, making them easy for sailors to catch when they landed on ships.