The blue-footed booby is a large seabird that lives in tropical and subtropical waters. As their name suggests, the blue-footed booby has distinctive bright blue feet. But why is this seabird called a “booby” and where does this name come from?
What is a blue-footed booby?
The blue-footed booby (Sula nebouxii) is a large seabird in the Sulidae family related to gannets and cormorants. There are two subspecies: the smaller Sula nebouxii nebouxii found in the eastern Pacific Ocean and the larger Sula nebouxii granti found in the western Atlantic Ocean. The blue-footed booby gets its name from its unique bright blue feet. Males have brighter blue feet than females. They use their blue feet in mating rituals to attract potential mates. Blue-footed boobies have long pointed blue-gray bills and mostly brown plumage with white undersides.
Blue-footed boobies are found in tropical and subtropical waters along the Pacific coast from California down to Chile and along the Atlantic coast in the Caribbean and off northern South America. They nest on the ground or in cliffs and generally lay 1-3 eggs per breeding season. They feed by diving feet-first into the ocean after fish. Blue-footed boobies are known for their elaborate mating dances, where males lift their bright blue feet high and whistle to attract mates.
Where does the name “booby” come from?
The term “booby” comes from the Spanish word “bobo” which means “stupid” or “foolish”. Early European sailors gave boobies this name because the birds had little fear of humans and could easily be caught.
In the 16th and 17th centuries, European explorers sailing to the Americas encountered blue-footed boobies and other related booby species. The birds they found were very tame and unafraid of people. Sailors could easily walk up to the boobies and grab them by hand. This behavior seemed foolish to the sailors, so they referred to the birds as “bobos” meaning fools or dunces. The name booby stuck for the genus Sula which includes the blue-footed booby.
Blue-footed booby behavior
Blue-footed boobies do indeed act quite foolishly tame around humans compared to other wild birds. There are several theories as to why blue-footed boobies exhibit this unusual tameness:
- They live on remote islands with few natural predators, so they have little innate fear of other animals including humans.
- They are slow and clumsy on land, so they cannot effectively flee from predators.
- Their diet consists entirely of fish captured by diving into water. They only feel safe in the water and have limited defenses on land.
- Their clumsiness on land and lack of land predators led to an evolutionary process whereby the boobies do not perceive humans as threats.
Whatever the exact reason, their unusually tameness around humans paired with their clumsy waddling walk gave them the reputation of being foolish birds or “boobies” to early European sailors.
Blue-footed booby feeding
Blue-footed boobies are oceanic birds that cannot swim. They hunt for fish by diving from the air in spectacular plunges into the sea. They hit the water feet-first at high speeds, which stuns or kills prey that they then seize with their beak. Their diet is almost 100% fish including sardines, anchovies, flying fish, and mackerel. Occasionally they will eat squid and crustaceans.
Blue-footed boobies hunt singly rather than in groups. They soar to locate fish, then half-close their wings and plummet sharply into the sea. They have been observed diving from heights over 30m (100ft). The impact when diving from such heights stuns small fish and makes them easy to catch. Their partially closed wings provide lift to help the booby resurface after impact.
Blue-footed booby diving skills improve with age and experience. Young fledglings often belly-flop awkwardly when first learning to dive, resulting in bruised chests. Their diving improves rapidly with practice. Expert adults can dive from high altitude and resurface from deep below with prey in their beak.
Blue-footed booby diving facts
- Dives from heights over 30m (100ft)
- Reaches speeds over 85 km/h (50mph) while diving
- Impacts the water feet-first to stun prey
- Catches prey up to 1m (3ft) deep below surface
- Catches fish including sardines, anchovies, and flying fish
Blue-footed booby reproduction
Blue-footed boobies exhibit an elaborate courtship display. Males lift their bright blue feet high and whistle to attract the attention of females. They point their bills skyward and spread their wings as they strut and dance before prospective mates.
Females will watch the displays of multiple males before selecting a mate. The blue coloration of the males’ feet comes from carotenoid pigments obtained through their fish diet. Females likely interpret the brightness of the males’ feet as a sign of his fishing ability to provide for their chicks.
Mating pairs engage in further ritual displays including sky-pointing, gift-giving, and vocal calls. Once paired, they maintain their bond over multiple breeding seasons. The mated pair engages in elaborate greeting rituals whenever they reunite at the breeding colony.
The female lays 1-3 eggs in a simple scrape nest on the ground, cliffs, or in bushes or trees. Both parents incubate the eggs and care for the chicks by feeding regurgitated fish. Chicks fledge and leave the nest at 2-3 months old. The blue-footed booby breeding cycle takes approximately 6 months from egg-laying to fledging of chicks.
Blue-footed booby breeding facts
- Males display bright blue feet to attract mates
- Elaborate courtship dancing and vocalizations
- Long-term pair bonds over multiple seasons
- Females lay 1-3 eggs
- Chicks fledge at 2-3 months old
- Breeding cycle takes 6 months
Threats and conservation
Blue-footed boobies are a widespread species found on islands throughout the tropical Pacific and Atlantic Oceans. However, there are several threats to their long-term survival:
- Habitat degradation – Nesting habitat is degraded by invasive species and human use of coastal islands
- Disturbance – Human activity near breeding colonies can displace nesting birds
- Pollution – Ocean pollution such as oil spills and plastic impact feeding and breeding
- Climate change – Rising sea levels and ocean warming may impact breeding
- Fisheries – Overfishing of anchovy, sardines, and other food sources
Conservation measures are needed to protect blue-footed booby breeding habitat and food sources. Creating protected areas around their nesting colonies offers immediate protection. Reducing ocean pollution and impacts of climate change are longer-term conservation goals.
While still widespread, some local populations have declined significantly, such as in the Galapagos. Continued monitoring and conservation will be needed to ensure blue-footed boobies remain bright-footed ocean acrobats for generations to come.
Conclusion
In summary, the blue-footed booby got its name from early European sailors who thought the tame birds were foolish or “boobies”. Their unusual tameness likely results from their evolution on remote islands with few predators. Blue-footed boobies are highly specialized fish-eaters that dive from great heights at high speeds to stun small fish. Their elaborate breeding rituals highlight their bright blue feet which females use to evaluate males. While still widespread, habitat loss, human disturbance, pollution, climate change, and overfishing impact blue-footed booby populations, so continued conservation will be necessary.
