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Overview

Distribution

circum-(sub)tropical
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Masked boobies are fairly widespread; they are found primarily in the Atlantic and Pacific oceans. In the United States they are restricted to the three Hawaiian islands of Lehau, Moku Manu and Kaula. They are found mainly in the tropics. Masked boobies are found off the Yucatan peninsula and in much of South America. There are a variety of boobies with different ranges, but masked boobies are found on many islands between 30 degrees N and 30 degrees S, with tiny habitats from the Pacific to the Red Sea, and even on islands near Indonesia and Australia.

Biogeographic Regions: oriental (Native ); ethiopian (Native ); neotropical (Native ); australian (Native ); oceanic islands (Native )

  • Anderson, D. 1993. Sula dactylatra - Masked Booby. The Birds of North America, No. 73, 1993: 1-16.
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Range Description

This species ranges widely in tropical waters, being found in every ocean on or off nearly every coast except the eastern Atlantic, northern Indian Ocean and the central-eastern Pacific (del Hoyo et al. 1992).
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occurs (regularly, as a native taxon) in multiple nations

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National Distribution

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Breeding

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Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) BREEDING: Atlantic-Caribbean: Islands off Yucatan, Cayman Islands, southwest of Jamaica, Puerto Rico, Virgin Islands, Florida Keys (Dry Tortugas, occasionally), Lesser Antilles, off Venezuela and Brazil and east to Ascension Island (AOU 1998, Clapp and Buckley 1984); in West Indies, an extremely local resident, generally seen only in breeding areas and adjacent seas (Raffaele 1983). Pacific: Islands off western Mexico, from the Hawaiian (Kure to Kaula Rock, and Moku Manu) and Ryukyu Islands south to eastern Australia and the Kermadec, Tuamotu, and Easter Islands, and islands off Peru and Chile. Indian Ocean: from the Gulf of Aden and Cocos-Keeling and Christmas Islands south to the Mascarenes and northwestern Australia. Formerly in the southern Bahamas (AOU 1998, 2000). RANGES AT SEA: from Bahamas and the Yucatan south through breeding range, and generally thoughout breeding range in Pacific and Indian Oceans south to western Mexico, eastern Australia, and South Africa (AOU 1998). Some old sight reports may refer to S. GRANTI (AOU 2000).

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Physical Description

Morphology

Masked boobies are graceful birds, their body is white, they have black on thier wings and tails and a black mask around their beak and eyes. They are the biggest species of boobies. Females are larger than males, ranging from 75 to 86 cm long, males are from 74 to 82 cm long. They weigh from 1220 to 2353 g and have wingspans of 152 cm, on average. It is difficult to tell males and females apart because they both have bright white plumage as adults; young boobies are often mistaken for northern gannets (Morus bassanus). Masked boobies are born naked but are completely covered with feathers after 35 to 40 days. Juveniles are grey with white underparts and do not look like adults until their fourth year.

Range mass: 1220 to 2353 g.

Range length: 74 to 86 cm.

Average wingspan: 152 cm.

Sexual Dimorphism: sexes alike; female larger

Other Physical Features: endothermic ; bilateral symmetry

Average basal metabolic rate: 5.5209 W.

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Size

Length: 91 cm

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Diagnostic Description

Description

Length: 81-92 cm. Colour: adult white with black flight feathers and tail; facial and gular skin blackish to dark blue-grey; bill orange to yellow-green with black at base; legs and feet grey; eye yellow; immature dark grey-brown above with a dark brown head and white collar; underside of wings white with broad dark trailing edge and dark band parallel to leading edge; bill olive to pale horn. Habitat: open ocean. Distribution: Palaeartic migrant (<313><316><318>)
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Ecology

Habitat

Boobies prefer to live on small, flat islands without trees. They often nest on the edges of cliffs or in flat areas that allow for easy take-off. They spend much of their time foraging over the ocean far from land.

Habitat Regions: tropical ; terrestrial ; saltwater or marine

Aquatic Biomes: pelagic ; coastal

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Habitat and Ecology

Habitat and Ecology
This strictly marine species can normally be found over pelagic waters, preferring deeper waters than other boobies. It feeds on large species of shoaling fish, especially flying fish, but will also take large squid. Its breeding season depends on locality, forming small to medium-sized colonies of variable densities on rocky islands offshore. Nests are preferably built on cliff ledges, but a variety of other sites are used (del Hoyo et al. 1992).

Systems
  • Marine
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Comments: Pelagic. Prefers warm deep waters (Stiles and Skutch 1989). In West Indies, generally in seas adjacent to breeding areas (Raffaele 1983). Frequently perches on floating debris in drift lines (Ridgely and Gwynne 1989). Roosts and Nests exclusively on smaller oceanic islands, especially flat, unforested terrain within 30 degrees of the Equator.

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Depth range based on 255 specimens in 2 taxa.
Water temperature and chemistry ranges based on 219 samples.

Environmental ranges
  Depth range (m): 0 - 0
  Temperature range (°C): 16.316 - 28.632
  Nitrate (umol/L): 0.050 - 3.497
  Salinity (PPS): 32.479 - 36.472
  Oxygen (ml/l): 4.363 - 5.685
  Phosphate (umol/l): 0.056 - 0.435
  Silicate (umol/l): 0.769 - 4.671

Graphical representation

Temperature range (°C): 16.316 - 28.632

Nitrate (umol/L): 0.050 - 3.497

Salinity (PPS): 32.479 - 36.472

Oxygen (ml/l): 4.363 - 5.685

Phosphate (umol/l): 0.056 - 0.435

Silicate (umol/l): 0.769 - 4.671
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

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Migration

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

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Trophic Strategy

Boobies have a diet consisting mostly of fish and squid. They catch their prey by diving from heights of up to 30 m. When collecting food for offspring, boobies usually tend to stay closer to land, otherwise they hunt around 65 km from shore.

Animal Foods: fish; mollusks

Primary Diet: carnivore (Piscivore , Molluscivore )

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Comments: Dives from air to water surface; eats mostly fishes, also squid. Flying fishes are preferred food (Stiles and Skutch 1989).

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Associations

Because masked boobies do not occur in dense populations, they do not seriously affect fish populations where they feed, nor are they important food sources for predators.

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There are no known predators of masked boobies. Because they are not usually found in dense populations and because they nest on islands, it might be hard for predators to rely on them as prey.

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Known prey organisms

Sula dactylatra preys on:
Actinopterygii
Mollusca

This list may not be complete but is based on published studies.
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General Ecology

Nonbreeding: usually solitary or in small loose groups (Stiles and Skutch 1989).

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Life History and Behavior

Behavior

Males have a high-pitched whistle while females have a more "honky" sounding call. Males will communicate by calling during their courtship displays or when they are frightened or alarmed. Females only call for help and as a warning. Both sexes are usually silent at night.

Communication Channels: visual ; acoustic

Perception Channels: visual ; tactile ; acoustic ; chemical

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Life Expectancy

Masked Boobies have a lifespan of 15 to 20 years; the longest known lifespan is 20 years.

Range lifespan

Status: wild:
15 to 20 years.

Average lifespan

Status: wild:
306 months.

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Lifespan, longevity, and ageing

Maximum longevity: 25.5 years (wild)
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Reproduction

Boobies have intricate mating rituals; males attract females by stretching out their necks and presenting gifts such as small stones and feathers to their perspective mates. After a slow walk they copulate; copulation takes ten to twenty seconds, and the female begins incubating immediately after laying the first egg.

Mating System: monogamous

Breeding seasons vary widely throughout the range of masked boobies; they can occur from February to August, January to July, and August to March. Masked boobies nest colonially; their nests are small hollows in the ground. The female usually lays two eggs. Incubation lasts 43 days on average. Masked boobies do not have brood patches, so they incubate the eggs with their feet. The first chick to hatch kicks the second chick out of the nest, so parents raise only one offspring. The chick fledges in 109 to 151 days and is intependent in one to two months. Juveniles reach sexual maturity in 3 to 5 years.

Breeding season: Breeding seaons vary widely throughout the range of masked boobies.

Range eggs per season: 1 to 2.

Average eggs per season: 1.

Average time to hatching: 43 days.

Range fledging age: 109 to 151 days.

Range time to independence: 1 to 2 months.

Range age at sexual or reproductive maturity (female): 3 to 5 years.

Range age at sexual or reproductive maturity (male): 3 to 5 years.

Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous

Average eggs per season: 1.

Both males and femles incubate the eggs. The first chick to hatch kicks the second chick out of the nest, so the parents only raise one offspring. Chicks are usually fed only once or twice a day. Both parents feed their young, but females may bring more food to the nest than males. Both parents continue to protect and feed their chick for one to two months after it fledges.

Parental Investment: no parental involvement; altricial ; pre-hatching/birth (Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female)

  • Anderson, D. 1993. Sula dactylatra - Masked Booby. The Birds of North America, No. 73, 1993: 1-16.
  • Kepler, C. 1969. Breeding Biology of the Blue-Faced Booby on Green Island, Kure Atoll. Cambridge, MA: Nuttall Ornithological Club.
  • National Wildlife Refuge, 2000. "Masked Booby" (On-line). Accessed April 20, 2004 at http://midway.fws.gov/wildlife/mabo.html.
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In Puerto Rico and Virgin Islands, egg-laying apparently peaks in January-June and September-November; January-May in Hawaii; may nest any month. Clutch size is 1-2 (usually 2). Incubation, by both sexes, lasts 41-43 days. One nestling survives. Young are tended by both sexes, first flies at about 102 days.

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Molecular Biology and Genetics

Molecular Biology

Barcode data: Sula dactylatra

The following is a representative barcode sequence, the centroid of all available sequences for this species.


There are 2 barcode sequences available from BOLD and GenBank.

Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.

See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

CCTATACCTAATCTTCGGCGCCTGAGCTGGTATAGTTGGAACAGCACTCAGCCTACTCATCCGAGCAGAACTAGGCCAACCTGGAACTCTCCTAGGAGATGATCAAATCTACAATGTAATTGTTACCGCTCATGCCTTCGTAATAATCTTTTTTATAGTAATACCAATCATAATCGGAGGATTTGGAAACTGACTAGTGCCACTCATAATTGGTGCTCCTGACATAGCATTCCCACGCATAAACAACATAAGCTTCTGACTACTCCCACCATCCTTCCTACTCCTTCTAGCCTCATCAACGGTAGAAGCAGGCGCGGGTACGGGATGAACTGTATACCCCCCATTAGCTGGAAACCTAGCCCACGCTGGAGCTTCAGTCGACCTAGCCATCTTCTCCCTTCACCTAGCAGGTGTCTCCTCCATCCTAGGAGCAATCAACTTTATTACAACTGCAATCAACATAAAACCTCCAGCTCTCTCACAATACCAAACCCCACTATTCGTTTGATCAGTCCTCATTACCGCCGTCCTACTACTACTCTCACTCCCAGTCCTCGCCGCTGGCATTACCATACTCTTAACGGACCGAAACCTAAACACCACATTTTTCGACCCTGCAGGAGGAGGAGACCCAGTACTATACCAGCACCTCNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
-- end --

Download FASTA File

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Statistics of barcoding coverage: Sula dactylatra

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 1
Specimens with Barcodes: 8
Species With Barcodes: 1
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Conservation

Conservation Status

Interactions with humans seem to have had little effect on the species. Thousands of tourists pass close by their nests in the Galapagos, seemingly without any negative effects. Though there have been a few cases of boobies caught in fishing traps, these numbers are reportedly small.

CITES: no special status

IUCN Red List of Threatened Species: least concern

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IUCN Red List Assessment


Red List Category
LC
Least Concern

Red List Criteria

Version
3.1

Year Assessed
2012

Assessor/s
BirdLife International

Reviewer/s
Butchart, S. & Symes, A.

Contributor/s

Justification
This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
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National NatureServe Conservation Status

United States

Rounded National Status Rank: NNRB - Unranked

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NatureServe Conservation Status

Rounded Global Status Rank: G5 - Secure

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Population

Population
The global population size has not been quantified, but this species is described as 'fairly common' (Stotz et al. (1996).

Population Trend
Decreasing
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Management

Needs: van Halewyn and Norton (1984) recommended that all nesting sites of this rare and local booby in the Caribbean region should be fully protected.

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Relevance to Humans and Ecosystems

Benefits

There are no known adverse affects of masked boobies on humans.

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Fishermen sometimes find schools of tuna by following feeding boobies; without knowing it, boobies provide fisherman with information on the best places to find fish. Boobies are also popular among birdwatchers.

Positive Impacts: ecotourism

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Wikipedia

Masked booby

"Parasula" redirects here. The fossil genus established by C.J.O. Harrison is properly called Empheresula.

The masked booby (Sula dactylatra) is a large seabird of the booby family, Sulidae. This species breeds on islands in tropical oceans, except in the eastern Atlantic; in the eastern Pacific it is replaced by the Nazca booby, Sula granti, which was formerly regarded as a subspecies of masked booby.[2][3] It is also called the masked gannet or the blue-faced booby.

A conspicuous and distinct gannet-like species, it was proposed for separation to a monotypic subgenus Pseudosula, but the Nazca booby and as it seems also the brown booby (S. leucogaster) are quite close relatives.

Classification[edit]

First described by French naturalist René-Primevère Lesson in 1831, the masked booby is one of six species of booby in the genus Sula. The Nazca booby (S. granti) was formerly regarded as a subspecies. There are four subspecies, none of which is separable at sea:

  • S. d. personata van Tets, Meredith, Fullagar & Davidson, 1988: Austropacific masked booby
Breeds in the central and western Pacific and around Australia, as well as off Mexico and on Clipperton Island. Birds of the latter two locations have been separated as subspecies granti, and the north west Australian population has been named as subspecies bedouti, but neither is usually considered valid.
  • S. d. dactylatra van Tets, Meredith, Fullagar & Davidson, 1988: Atlantic masked booby
Breeds in the Caribbean and some Atlantic islands including Ascension Island. It has recently started breeding off Tobago, formerly being known in this area only from a single sight record from an oil rig off Trinidad.
  • S. d. melanops van Tets, Meredith, Fullagar & Davidson, 1988: Western Indian Ocean masked booby
Breeds in the western Indian Ocean.
  • S. d. tasmani (including S. d. fullagari) van Tets, Meredith, Fullagar & Davidson, 1988: Tasman booby or Lord Howe masked booby
The form breeding on Lord Howe and the Kermadec Islands. Large prehistoric specimens known from the former and Norfolk Island are sometimes considered a distinct "species" (properly: subspecies). If this is correct, the extant population's name would be S. d. tasmani as S. d. fullagari was described after S. tasmani. Comparison of ancient DNA form tasmani specimens and living fullagari indicates that they are not distinct.

Description[edit]

This is the largest booby, at 74–91 cm (29–36 in) long, with a 137–165 cm (54–65 in) wingspan and 1.2–2.35 kg (2.6–5.2 lb) weight.[4] Adults are white with pointed black wings, a pointed black tail, and a dark grey facemask. The sexes are similar, but the male has a yellow bill, and the female's is greenish yellow; during the breeding season they have a patch of bare, bluish skin at the base of the bill. Juveniles are brownish on the head and upperparts, with a whitish rump and neck collar. The underparts are white. Adult plumage is acquired over two years.

The masked booby is silent at sea, but has a reedy whistling greeting call at the nesting colonies. While on the breeding grounds, these birds display a wide range of hissing and quacking notes.

Behaviour[edit]

Masked boobies are spectacular divers, plunging diagonally into the ocean at high speed. They mainly eat small fish, including flying fish. This is a fairly sedentary bird, wintering at sea, but rarely seen far away from the breeding colonies. However, Caribbean birds occasionally wander north to warm southern Gulf Stream waters off the eastern seaboard of the United States. More remarkably, there have been three western Palaearctic records of masked booby, presumably dactylatra, all from Spanish waters, although one of these also entered French territorial areas.

Breeding[edit]

The masked booby nests in small colonies, laying two chalky white eggs on sandy beaches in shallow depressions, which are incubated by both adults for 45 days. In most cases, the first chick will kill its smaller, weaker sibling after it hatches.[5] Siblicide has been well studied in this species; researchers such as David Anderson have demonstrated that while the boobies can manage to feed two chicks if siblicide is prevented, they do so at a steep penalty to health and future reproductive success.[6][7][8]

Compared to other species of boobies such as the blue-footed booby, siblicide is obligatory in the masked booby. One reason is because the masked boobies build very shallow flat nests, so older chicks can expel their younger siblings with relative ease. Blue-footed booby parents, meanwhile, build nests with steeper sides, thus preventing some older chicks from engaging in siblicidal behaviour.[9]

References[edit]

  1. ^ BirdLife International (2012). "Sula dactylatra". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013. 
  2. ^ Pitman, R. L.; Jehl, J. R. (1998): Geographic variation and reassessment of species limits in the "Masked" Boobies of the eastern Pacific Ocean. Wilson Bulletin 110(2): 155-70
  3. ^ Friesen, V. L.; Anderson, D. J.; Steeves, T. E.; Jones, H. & Schreiber, E. A. (2002): Molecular Support for Species Status of the Nazca Booby (Sula granti). Auk 119(3): 820–26. [English with Spanish abstract] DOI: 10.1642/0004-8038(2002)119[0820:MSFSSO]2.0.CO;2 PDF fulltext
  4. ^ [1] (2011).
  5. ^ Mack, Alison. 1997. "Natural born killers." Earth 6, no. 3: 12. General Science Collection, EBSCOhost (accessed May 4, 2007).
  6. ^ Anderson, David J. 1990. "Evaluation of Obligate Suicide in Boobies. 1. A Test of the Insurance-Egg Hypothesis." The American Naturalist 135, vol. 3: 334-350
  7. ^ Anderson, David J. 1990. "Evolution of Obligate Siblicide in Boobies. 2: Food Limitation and Parent-Offspring Conflict" Evolution 44 no. 8: 2069-2082
  8. ^ Alda, Alan (Host). (1999). Voyage to the Galapagos [Television series episode]. Scientific American Frontiers. Arlington, Virginia: Public Broadcasting Service. (transcript here: http://www.pbs.org/saf/transcripts/transcript1001.htm)
  9. ^ Anderson, David J. (1995). "The Role of Parents in Siblicidal Brood Reduction of Two Booby Species". The Auk 112 (4): 860–869. doi:10.2307/4089018. 
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Notes

Description and cool facts

A large seabird of tropical oceans, the Masked Booby is only a rare visitor to North America. It has attempted to breed in the Dry Tortugas in Florida, but it is most frequently encountered at sea in the Gulf of Mexico or off the southern Atlantic states.

The population of Masked Boobies breeding along the Pacific Coast of northern South America, including the Galapagos, was recently recognized as a separate species, the Nazca Booby. The Nazca Booby has an orange, not yellow, bill and is smaller with a significantly shorter, shallower bill. Whereas the Masked Booby usually nests on low, flat areas, the Nazca Booby uses cliffs and steep slopes.

Although the Masked Booby regularly lays two eggs, it never raises two young. The first egg is laid four to nine days before the second, and the older chick always ejects the second from the nest. The parents do not protect or feed the ejected chick, and it is quickly scavenged by a host of associated crabs, landbirds, and frigatebirds.

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Names and Taxonomy

Taxonomy

Comments: S. dactylatra formerly included S. granti, the Nazca Booby, but, on the basis of differences in bill color, size and proportions, plumages and nesting habitat, the latter was given full species status by AOU (2000), as proposed by Pitman and Jehl (1998). The breeding range of S. granti is restricted to the Galapagos Islands and Isla La Plata, Ecuador; Malpelo Island, Colombia; and (in small numbers) Clipperton Island and the Revillagigedos, Mexico.

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