Blue-footed Booby
Sula nebouxii
Suliformes Order – Sulidae Family
BIOMETRICS:
Length: 76-84 cm
Wingspan: 150 cm
Weight: 1500 g
LONGEVITY: Up to 17 years
DESCRIPTION:
Blue-footed Booby is an elegant seabird, well known for its amazing mating dance.
Fr: Fou à pieds bleus
All : Blaufußtölpel
Esp: Piquero Camanay
Ital: Sula piediazzurri
Nd: Blauwpootgent
Russe: Голубоногая олуша
Sd: Blåfotad sula
Photographers:
Tom Merigan
Tom Merigan’s Photo Galleries
Tom Grey
Tom Grey's Bird Pictures
Text by Nicole Bouglouan
Sources:
HANDBOOK OF THE BIRDS OF THE WORLD vol 1 by Josep del Hoyo-Andrew Elliot-Jordi Sargatal - Lynx Edicions - ISBN: 8487334105
A GUIDE TO THE BIRDS OF MEXICO AND NORTHERN CENTRAL AMERICA by Steve N. G. Howell, Sophie Webb - Oxford University Press - ISBN: 0198540124
Wikipedia (Wikipedia, The Free Encyclopedia)
Adult male has brown upperparts including the wings. Mantle is brown, with white edged feathers, and we can see a white patch on the upper back. Tail is white with brown-tinged outer rectrices.
Underparts are white. Underwing is brownish with darker flight feathers.
The wings are narrow and long, and set far back on the body, very useful during the fishing actions.
Head and neck are white with brown bases of feathers, giving fine streaked pattern.
The long, pointed bill is blackish, as the bare skin of the face.
Eyes are pale yellow. Short legs and webbed feet are blue.
Both sexes are similar in plumage, but female is larger than male.
Juvenile has browner head and breast, and the bare parts are duller than in adults. Eyes are dusky. The young needs two years to attaint the adult pattern.
We find two subspecies:
S.n.nebouxii, from E Pacific. This species breeds in NW Mexico and Panama to Northern Peru.
S.n. excisa, from Galapagos. This species is larger and paler.
VOICE:
Blue-footed Booby male utters plaintive sounds and thin whistles. Female has very different calls. She gives resonant trumpeting quacks and honks.
HABITAT:
Blue-footed Booby is strictly marine. During the breeding season, the birds nest on rocky coasts, cliffs and islets. There is little or not vegetation in these areas.
RANGE:
Blue-footed Booby lives along the coasts of eastern Pacific Ocean. It is found in the Galapagos and in California. It breeds from California to Peru.
BEHAVIOUR:
Blue-footed Booby feeds mainly on fish. As all the birds of this family, it performs spectacular plunge-dives from great heights, allowing it to reach the large shoals of fish and squid. Preferred preys are sardina, anchovies and mackerels. It also takes flying fish (Exocoetidae) and squid (Ommastrephidae).
Boobies usually fly higher than other seabirds when foraging. They have binocular vision, making easier to locate the preys.
They may plunge from 10-30 metres up and sometimes higher. Before to dive, the bird adjusts the direction and enters the water at top speed. At this moment, wings are pushed backwards, parallel to the body.
Blue-footed Booby is gregarious and forages in large flocks of up to 200 birds. They can catch flying fish in the air, and often feed in shallow water.
This species may perform a kind of collaborative fishing. The birds fly along in groups, and one male calls all members when the preys are detected, and all the birds dive at the same time.
Blue-footed Booby is well known for its mating dance. It has typical displays in which the male shows off the blue feet to potential mate, by performing a high-stepping strut.
Male also performs “sky-pointing» with held neck and head, and bill pointed upwards, while wings and tail are raised. This behaviour is used to strengthen the pair-bonds. Displays by male are accompanied by whistles.
Blue-footed Booby may move, but mainly according to the food resources. If food sources are abundant, the birds stay close to the colony-site after the breeding season.
FLIGHT:
Blue-footed Booby has long, pointed, narrow wings, allowing great manoeuvrability in flight. Boobies have cigar-shaped bodies, giving them beautiful aerodynamic silhouette when in the air.
REPRODUCTION:
Blue-footed Boobies form large nesting colonies. They nest in rocky areas and the rudimentary nest is on the ground. It is a depression with a rim of excreta (guano).
Female lays 2-3 pale blue or green eggs. Incubation by both parents lasts about 41-45 days. Boobies have not brood patch and they incubate their eggs with the webbed feet.
At hatching, chicks are covered with white down. They are placed on top of adult’s webs where they are brooded for the first days.
Male provides food to chicks and female during the first days. Then, both parents feed the young with regurgitated fish. They fledge at about 3 months of age, and parents care them for 55 days more. Young birds can breed at 2-3 years.
DIET:
Blue-footed Booby feeds on fish, flying fish and squid. It performs several fishing techniques, and the most typical is the plunge-diving. The bird dives from great heights into the shoals, and may reach about 25-30 metres depth.
They are opportunist birds and they may feed on other preys at other food sources, according to the season and the circumstances.
PROTECTION / THREATS / STATUS:
Blue-footed Boobies have small world population through relatively restricted range. However, breeding, numbers and population dynamics are well managed and seem to be more stable than in other species.
They are vulnerable to predation by introduced species in the Galapagos.