Ascension Island is one of the most important warm-water seabird stations in the world, and the most important seabird breeding site in the tropical Atlantic. It supports over 400,000 seabirds of 11 species. The most important site for seabirds on Ascension is the small offshore Boatswainbird Island, though some species nest on offshore stacks, mainland cliffs and the letterbox peninsula.
The present sizes of the seabird populations are thought to be only a fraction of those found before man's colonisation in 1815, when millions of seabirds nested in large colonies on the mainland.
The Red-footed booby (Sula sula) is a large seabird of the booby family, Sulidae. Three varieties of these gannet-like birds are found on Ascension. The Masked booby is a large powerful seabird and the largest of the three. The Red-footed booby (length 71 cm with a wingspan of 91-101 cm) is similar in size to the Brown booby but is in fact the smallest member of the booby family.
As suggested by the name, adults always have red feet. They also have pale blue bills but the plumage can vary as the Red-footed booby comes in a confusing array of variations (phases or colour morphs), ranging from individuals that are all white except for blackish on the wing, to individuals that are entirely dark brown. Some birds fail to fit neatly into any of the typical colour morph categories, and many variations exist. Colour morphs do not segregate reproductively or geographically; individuals representing several morphs breed in a single colony. Juveniles are wholly grey brown with yellowish grey legs.
Throughout its range, except on Ascension and Trindade, the Red-footed booby is a tree-nesting species. This would explain the shortness of its legs compared to those of other boobies.
Red-footed booby pairs may remain together over several seasons. They perform elaborate greeting rituals including harsh squawks, the male's display of his blue throat and short dances. They breed on islands in most tropical oceans. When not breeding they spend most of the time at sea, and are therefore rarely seen away from breeding colonies. The female lays just a single egg that is bluish in colour with a chalky covering. It can be variable in shape but averages 63 x 41mm. The eggs are incubated by both adults for 44–46 days. It may be three months before the young first fly, and five months before they make extensive flights.
At Ascension they breed mainly on Boatswainbird Island and various off-shore stacks. Only about 30 individuals of this species are found on Ascension, representing about 10% of the Atlantic population.
Red-footed boobies are powerful and agile fliers, but clumsy in take-offs and landings. They are spectacular divers, plunging into the ocean at high speeds to catch prey. They mainly eat small fish or squid which gather in groups near the surface. Flying fish are also taken in flight, especially when being chased by underwater predators. Like all boobies, the Red-footed booby never carries its prey in its beak. Instead, it always swallows it before flying.
The oldest recorded Red-footed booby was at least 22 years, 11 months old.
Designer: Andrew Robinson
Printer: Cartor Security Printing
Process: Stochastic lithography
Stamp Size: 28 x 42 mm
Sheet Format: 10
Sheetlet layout: 16 (4x4)
Perforation: 13 ½ x 13 ¼ per 2cms
Release Date: 22 February 2016
Production Co-ordination: Creative Direction (Worldwide) Ltd
The WWF initials and Panda device © 1986 WWF, with the authorisation of WWF, registered Trademark owner.