Species of bird
The
red-footed booby
(
Sula sula
) is a large
seabird
of the
booby
family,
Sulidae
. Adults always have red feet, but the colour of the
plumage
varies. They are powerful and agile fliers, but they are clumsy in takeoffs and landings. They are found widely in the tropics, and breed
colonially
in coastal regions, especially islands. The species faces few natural or man-made threats, although its population is declining; it is considered to be a
least-concern species
by the
International Union for Conservation of Nature
(IUCN).
Taxonomy
[
edit
]
The red-footed booby was
formally described
by the Swedish naturalist
Carl Linnaeus
in 1766, in the
twelfth edition
of his
Systema Naturae
. He gave it the
binomial name
Pelecanus sula
and described it based on a specimen from
Barbados
.
[3]
[4]
The present genus
Sula
was introduced by the French scientist
Mathurin Jacques Brisson
in 1760.
[5]
The word
Sula
is Norwegian for a
gannet
.
[6]
There are three subspecies:
[7]
- S. s. sula
(Linnaeus, 1766) ? Caribbean and southwest Atlantic islands
- S. s. rubripes
Gould
, 1838 ? tropical Pacific and Indian Oceans
- S. s. websteri
Rothschild
, 1898 ? eastern central Pacific
Description
[
edit
]
The red-footed booby is the smallest member of the
booby and gannet
family at about 70 cm (28 in) in length and with a
wingspan
of up to 152 cm (60 in).
[8]
The average weight of 490 adults from
Christmas Island
was 837 g (1.845 lb).
[9]
It has red legs, and its
bill
and throat pouch are coloured pink and blue. This species has several
morphs
. In the white morph the
plumage
is mostly white (the head often tinged yellowish) and the
flight feathers
are black. The black-tailed white morph is similar, but with a black tail, and can easily be confused with the
Nazca
and
masked boobies
. The brown morph is overall brown. The white-tailed brown morph is similar, but has a white belly, rump, and tail. The white-headed and white-tailed brown morph has a mostly white body, tail and head, and brown wings and back. The morphs commonly breed together, but in most regions one or two morphs predominates; for example, at the
Galapagos Islands
, most belong to the brown morph, though the white morph also occurs.
The sexes are similar, and juveniles are brownish with darker wings, and pale pinkish legs, while chicks are covered in dense white down.
Distribution
[
edit
]
The red-footed booby is widespread throughout the tropics of the Atlantic, Pacific, and Indian Oceans. In the Indian Ocean, it is found on
Aldabra
, the
Seychelles
,
Rodrigues
, the
Chagos Archipelago
, the
Cocos (Keeling) Islands
, and
Christmas Island
.
[10]
The red-footed booby has been
extirpated
from a large number of islands due to a combination of introduced predators and human predation, including the
Glorioso Islands
,
Assumption Island
,
Tikopia
,
Henderson Island
, the
Marquesas Islands
, the
Society Islands
, and
Desecheo Island
.
[10]
The species is a vagrant to
Sri Lanka
,
[11]
New Zealand,
[12]
and the United Kingdom.
[13]
Ecology and behaviour
[
edit
]
Breeding
[
edit
]
This species breeds on islands in most tropical oceans. When not breeding it spends most of the time at sea, and is therefore rarely seen away from breeding colonies. It nests in large colonies, laying one chalky blue egg in a stick nest, which is incubated by both adults for 44?46 days. The nest is usually placed in a tree or bush, but rarely it may nest on the ground. It may be three months before the young first fly, and five months before they make extensive flights.
Red-footed booby pairs may remain together over several seasons. They perform elaborate greeting rituals, including harsh squawks and the male's display of his blue throat, also including short dances.
Diet
[
edit
]
The diet of red-footed boobies consists mostly of
fish
(such as
Exocoetidae
flying fish and
Gempylidae
escolars) and
squid
.
[14]
Studies of the red-footed booby on
Christmas Island
have found that most fish eaten are 6?15 cm (2.4?5.9 in) long, with a maximum length of 20 cm (7.9 in), and most squid are 6?10 cm (2.4?3.9 in), with a maximum length of 15 cm (5.9 in). On
Aldabra
, the proportion of fish and squid in the diet varies between seasons; squid make up 21% of the diet by mass in the wet season and 1% in the dry season. They generally catch prey by diving into the ocean vertically from heights of 4 to 8 m (13 to 26 ft), although flying fish may be caught while in the air.
[10]
Predators and parasites
[
edit
]
Adult red-footed boobies are known to be hunted by
coconut crabs
; the crabs use their powerful claws to break the wings of boobies or catch them by their legs. One booby attacked while asleep on a low branch was killed by six coconut crabs over a period of several hours, while another caught after landing near the entrance to a crab burrow was dragged inside.
[15]
Red-footed booby nestlings and eggs are also attacked by a variety of predators, including rats, cats, pigs,
[10]
raptors,
[16]
and
Micronesian starlings
,
[17]
although introduced mammalian predators have a limited impact as the booby nests in trees.
[10]
However, the booby's habit of breeding on remote islands may be an adaptation to avoid predation;
[10]
on the
Galapagos Islands
, the red-footed booby does not nest on any islands inhabited by the
Galapagos hawk
, even when they have suitable conditions, and has been observed colonizing islands soon after the hawk is
extirpated
on them.
[18]
Humans eat both red-footed booby adults and nestlings; boobies will bite humans trying to catch them near their nest.
[10]
Parasites recorded from the species include the tick
Ornithodoros capensis
in nests and the
bird louse
Pectino pygus
in adults.
[10]
Conservation
[
edit
]
The
International Union for Conservation of Nature
(IUCN) lists the red-footed booby as a species of
least concern
, though the population worldwide is decreasing.
[2]
The warm phase (
El Nino
) of the
El Nino?Southern Oscillation
in 1982 and 1983 negatively affected breeding on Christmas Island as higher water temperatures reduced food supply. Where usually 6000 pairs nested, 30 pairs and the around 60 pairs attempted breeding in 1982 and 1983 respectively.
[19]
Gallery
[
edit
]
-
Red footed booby in flight over Half Moon Caye, Belize
-
Juvenile red-footed booby poking his head out of his nest on Half Moon Caye, Belize
-
Red-footed booby
-
Egg, Collection
Museum Wiesbaden
References
[
edit
]
- ^
"
Sula sula
Linnaeus 1766 (red-footed booby)"
.
PBDB
.
- ^
a
b
BirdLife International (2018).
"
Sula sula
"
.
IUCN Red List of Threatened Species
.
2018
: e.T22696694A132589278.
doi
:
10.2305/IUCN.UK.2018-2.RLTS.T22696694A132589278.en
. Retrieved
12 November
2021
.
- ^
Linnaeus, Carl
(1766).
Systema naturae : per regna tria natura, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis
[
The system of nature: through the three kingdoms of nature, according to classes, orders, genera, species, with characters, differences, synonyms, places
] (in Latin). Vol. 1, part 1 (12th ed.). Stockholm: Laurentii Salvii. p. 218.
- ^
Grant, Claude H. B.; Mackworth-Praed, C. W. (1933).
"The Correct Type-locality of the Red-footed Booby,
Sula sula sula
(Linnæus)"
.
Bulletin of the British Ornithologists' Club
.
53
: 185?187.
- ^
Brisson, Mathurin Jacques
(1760).
Ornithologie, ou, Methode contenant la division des oiseaux en ordres, sections, genres, especes & leurs varietes
(in French and Latin). Vol. 1. Paris: Jean-Baptiste Bauche.
Vol. 1 p. 60
,
Vol. 6 p.494
.
- ^
Jobling, James A. (2010).
The Helm Dictionary of Scientific Bird Names
. London: Christopher Helm. p.
373
.
ISBN
978-1-4081-2501-4
.
- ^
Gill, Frank
; Donsker, David, eds. (2017).
"Hamerkop, Shoebill, pelicans, boobies & cormorants"
.
World Bird List Version 7.3
. International Ornithologists' Union
. Retrieved
20 November
2017
.
- ^
"Red-footed Booby"
.
All About Birds
. Cornell Lab of Ornithology. Retrieved May 28, 2020.
- ^
CRC Handbook of Avian Body Masses, 2nd Edition
by John B. Dunning Jr. (Editor). CRC Press (2008),
ISBN
978-1-4200-6444-5
.
- ^
a
b
c
d
e
f
g
h
Schreiber, Elizabeth A.; Schreiber, R. W.; Schenk, G. A. (2020-03-04). Billerman, Shawn M.; Keeney, Brooke K.; Rodewald, Paul G.; Schulenberg, Thomas S. (eds.).
"Red-footed Booby (
Sula sula
)"
.
Birds of the World
. Cornell Lab of Ornithology.
doi
:
10.2173/bow.refboo.01
. Retrieved
2024-04-01
.
- ^
Amarasinghe, Chamara Jayaba; Bandara, Imesh Nuwan.
"Third confirmed record of the red-footed booby
Sula sula
from Sri Lanka"
.
academia
.
- ^
"
'Astonishing' first ever NZ sighting of red-footed booby"
. 23 January 2017
. Retrieved
2017-08-01
.
- ^
Digital, Douglass.
"Changes to the British List (16 August 17)"
.
British Ornithologists' Union
. Retrieved
2022-07-05
.
- ^
"Red-footed Booby Life History"
.
All about birds
. Retrieved
2024-04-21
.
- ^
Laidre, Mark E (2017).
"Ruler of the atoll: the world's largest land invertebrate"
.
Frontiers in Ecology and the Environment
.
15
(9): 527?528.
doi
:
10.1002/fee.1730
.
ISSN
1540-9295
.
- ^
Raine, Andre F.; Vynne, Megan; Driskill, Scott (2019).
"The impact of an introduced avian predator, the Barn Owl
Tyto alba
, on Hawaiian seabirds"
(PDF)
.
Marine Ornithology
.
47
: 35.
- ^
Reichel, James D.; Glass, Philip O. (1990).
"Micronesian Starling Predation on Seabird Eggs"
.
Emu - Austral Ornithology
.
90
(2): 135?136.
doi
:
10.1071/MU9900135
.
ISSN
0158-4197
.
- ^
Anderson, David J. (1991).
"Apparent predator?limited distribution of Galapagos Red?footed Boobies
Sula sula
"
.
Ibis
.
133
(1): 26?29.
doi
:
10.1111/j.1474-919X.1991.tb04805.x
.
ISSN
0019-1019
.
- ^
Schreiber, Ralph W.; Schreiber, Elizabeth Anne (1984). "Central Pacific Seabirds and the El Nino Southern Oscillation: 1982 to 1983 Perspectives".
Science
.
225
(4663): 713?716.
Bibcode
:
1984Sci...225..713S
.
doi
:
10.1126/science.225.4663.713
.
JSTOR
1693159
.
PMID
17810291
.
S2CID
40459951
.
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Sula sula
.