Birds, Mammals
and Reptiles of Fernando de Noronha
Note:
This online review is updated and revised continuously, as soon as results
of new scientific research become available. It therefore presents
state-of-the-art information on the topic it covers.
The Archipelago of Fernando de Noronha lies in the tropical
Atlantic Ocean, 3
degrees south of the equator and 345 kilometers northeast of Cabo de São
Roque, Brazil (Carleton and Olson 1999). It is the easternmost
outpost of the Neotropics and consists
of one main island (area = 16.9 square kilometers) with a string of approximately 12 minor islets (Olson 1994, Carleton
and Olson 1999).
The island and islets of the Fernando de Noronha
archipelago are volcanic in origin and have never been connected by land
bridge to the South American mainland. Consequently, all native
animals of the archipelago have colonized the islands by flight or rafting
over the sea.
On 10 August 1503, the renowned explorer Amerigo Vespucci landed on
the main island of Fernando
de Noronha and wrote the first descriptions of its fauna for science.
He found no humans living on the island, but noted that trees were plentiful
and that land birds and sea birds were in great abundance. The
only other animals he saw were lizards, snakes and "very big rats" (Carleton
and Olson 1999). At this early date, it is believed
that the main island was "almost entirely forested" (Olson 1994).
Today only secondary forest remains (Stattersfield et al. 1998) (
Photo 1, Photo
2, Photo 3)
In the present report, we review the
native birds, mammals and reptiles of the archipelago. Fernando de Noronha has no native
amphibians and freshwater fish, however a toad (Bufo schneideri) (Photo
4) and a tree frog (Scinax aff. ruber) (Photo 5) have been introduced there by
humans (Olson 1981; Oren 1984).
Land Birds
The following species of land birds breed
on Fernando de Noronha and are believed to have colonized the archipelago
naturally:
Noronha Vireo (Vireo gracilirostris)
(Photo 6)
Noronha Elaenia (Elaenia ridleyana) (Photo
7)
Eared Dove (Zenaida auriculata noronha) (Photo
8)
Cattle Egret
(Bubulcus ibis) (Photo
9)
In addition, Olson (1981) reported
finding fossils of
an undescribed, extinct flightless rail on the main island. He briefly
added that the species did not closely resemble any rail from the mainland
of Brazil.
The vireo and elaenia are endemic to the Fernando de Noronha archipelago,
while the Eared Dove is also found on the Brazilian mainland. The vireo
breeds only on the main island of Fernando de Noronha, while the elaenia breeds on
both the main island and on Ilha Rata, the largest of the islets (Ridley
1890; Olson 1981). In addition, the Elaenia has been seen on still another
islet in the archipelago, Ilha do Meio (Oren 1984). During his studies on the
main island, Olson (1981) found the vireo
and elaenia to be "most abundant in the remaining areas of forest on the eastern
end of the island and around the base of Morro do Pico." However,
he reported that both species also occurred less frequently in trees along
roadsides, in shrubby areas and near houses.
The Noronha Vireo is more sharply differentiated from its
mainland relatives than is either the elaenia or dove. Olson (1994)
describes it as curious and tame, allowing close approach by
humans. Compared to the Red-eyed Vireo (Vireo olivaceus)
complex from which it is derived, the Noronha Vireo is smaller in size, with
a "longer, more slender bill, and a much longer tail and tarsus. The
wing is rounded rather than pointed," but has the same surface area (Olson
1994).
These anatomical features can be considered "warbler-like
specializations for gleaning small insects from foliage" (Olson 1994).
Oren (1984) writes that the Noronha Vireo habitually hangs upside down,
gleaning insects and other arthropods from foliage, inflorescences and tree
trunks, and that it forages from "the top of the trees to the ground, where
it runs short distances after its prey, reminding one more of a wren than a
vireo." Nicoll (1904) found that the Noronha Vireo's actions resembled those of the European Reed Warbler (Acrocephalus scirpaceus),
and wrote that the vireo "is an active little bird, continually on the move
amongst the leaves, now and then darting out after an insect."
A relatively new immigrant to Fernando de Noronha
is the Cattle Egret.
This bird colonized the archipelago in the final years of the twentieth
century and spread over the main island. It also has a large nesting colony on one of the islets.
Many other species of land birds
from the Brazilian mainland casually
visit Fernando de Noronha each year, but do not
breed in the archipelago (Nacinovic and Teixeira 1989).
In addition, some escaped or liberated cagebirds such as the Red-cowled Cardinal (Paroaria dominicana)
have been introduced by humans and are now breeding on the main island
(Oren 1982). For these reasons, humans visiting Fernando de Noronha may see
additional land bird species
than the four discussed here.
Sea Birds
The following seabirds have been recorded breeding in the
Fernando de Noronha Archipelago:
Red-billed Tropicbird (Phaethon aethereus)
White-tailed Tropicbird
(Phaethon lepturus)
Masked Booby (Sula dactylatra)
Red-footed Booby (Sula sula) (Photo 10)
Brown Booby (Sula leucogaster) (Photo 11)
Magnificent Frigatebird (Fregata magnificens) (Photo
12)
Sooty Tern (Sterna fuscata)
Brown Noddy (Anous stolidus) (Photo 13)
(Photo 14)
Black Noddy (Anous minutus)
White Tern (Gygis alba) (Photo 15)
References: Sharpe 1890; Oren (1982); Nacinovic and Teixeira (1989)
The Rat of Fernando de Noronha
In 1503, the explorer Amerigo Vespucci found no mammals
on Fernando de Norohna except "very large rats."
Because subsequent visiters to the archipelago did not mention these large rats
and, because it is unlikely that old world rats (Rattus spp.) had colonized Fernando de Noronha at this early date, Ridley (1888)
proposed that the large rats seen by Vespucci belonged to a now extinct
species of rat-like mammal unknown to science.
In 1973, a joint US-Brazilian expedition, lead by the paleontologist Storrs
L. Olson visited Fernando de Noronha and discovered many fossils of a large
undescribed rat which may have been the species Vespucci saw. Carleton and Olson (1999) formally described this animal, the
rat of Fernando de Noronha, as both a
new genus and species: Noronhomys vespuccii. They named the genus after
the island of Fernando de Noronha because they believed the rat was endemic
to this island. They named the species after Amerigo Vespucci because
his writings were the only known reference suggesting "the existence of an
indigenous rodent on the island."
The rat of Fernando de Noronha was the only native land
mammal of the archipelago. When Carleton and Olson (1999) studied its
fossils, they found similarities in its morphology to the semi-aquatic marsh
rats (Holochilus and
Lundomys) of
the South American mainland. These researchers hypothesized that
Noronhomys, Holochilus and possibly Lundomys descended from a recent common
ancestor. Like the marsh rats of today, this ancestor may have lived
along marshes, streams and rivers, constructing its nests, "often in
clusters, in trees and grasses growing along streams" (Carleton and Olson
1999). It is easy to imagine how a group of these rodents could
have become stranded on a raft of vegetation that eroded from the river's edge and
was swept out to sea by currents and winds, eventually
being cast up onto Fernando de Noronha (Carleton and Olson 1999).
Three exotic rodents, the
roof rat (Rattus rattus), house
mouse (Mus
musculus), and rock cavy (Kerodon rupestris) now occur on Fernando de Noronha. The
first two are believed to
have colonized the island sometime after 1503, probably from ships visiting
the island (Carleton and Olson 1999). The rock cavy was successfully
introduced to Fernando de Noronha in 1967 (Oren 1984). Another mammal,
the domestic
cat (Felis catus) is also now present on Fernando de Noronha, as are
domestic livestock such as "goats, sheep, cattle, dogs and horses" (Oren 1984).
Marine Mammals
The spinner dolphin (Stenella longirostris) uses
Golfinhos Bay of the main island for resting and breeding (Maida and
Ferreira 1997; Silva & Silva 2009) Photo 16,
Photo 17. Its diurnal behavior there was studied in detail by
Silva et al. (2005a), who discovered that spinner dolphins function
as a food supplier to reef fishes. This is a novel ecological role,
never before reported for cetaceans.
The feces, vomits and parasites of spinner dolphins
are eaten regularly by many species of coral reef fishes
at Fernando de Noronha (Sazima et al. 2003, 2006). The black durgon (Melichthys niger) is the most
ubiquitous of these offal-feeding fishes and, when associating with the
spinner dolphins, its group size is positively correlated with dolphin group
size (Sazima et al. 2003, 2006), Photo 18.
The spinner dolphin
feeds on fishes, squids and prawns. Individual fish pursuit and
coordinated fish school herding are the two hunting tactics most frequently
seen. (Silva et al. 2007)
Spinner dolphins at Fernando de Noronha
occasionally hybridize with other dolphin species (Silva et al. 2005b).
The whalesucker (Remora australis),
an oceanic diskfish that attaches only to cetaceans, has been found
year-round on the
spinner dolphins at Fernando de Noronha (Silva-Jr. and Sazima 2003, 2006),
Photo 19. The number of whalesuckers
found per dolphin ranged from one to three (Silva and Sazima 2006).
The
highly social nature of the dolphins may facilitate mating encounters
between individual whalesuckers attached to different dolphins (Silva
and Sazima 2003, 2006).
Silva and Sazima (2006) observed whalesuckers
cleaning wounds of the spinner dolphins and whalesuckers feeding on dolphin
feces. The dolphin provides the whale sucker with free transportation,
a place to live and mate, and "perhaps protection from sharks, tunas and
larger dolphins (Silva and Sazima 2006)."
Terrestrial Reptiles
Two endemic species of reptiles are present in the
archipelago: a worm-lizard (Amphisbaena ridleyi) and the
Noronha skink (Trachylepsis atlantica). In addition, the tegu lizard (Tupinambis merianae)
and the house gecko (Hemidactylus mabouia) have been introduced
by humans (Olson 1981; Oren 1984).
The worm-lizard is limbless and is undoubtedly the "snake"
seen by Amerigo Vespucci in 1503. The serpentine appearance of this
lizard "would suggest a snake
to anyone save an experienced herpetologist (Carleton and Olson 1999)." (See
Photo 20).
The Noronha worm-lizard is a truly
distinct form of worm-lizard, with a uniquely derived molarform dentition
for feeding on snails (Pregill 1984). On the slopes of
Morro do Pico, which is the highest point (321 m) on the main island, the Noronha
worm-lizard is more abundant than worm-lizards
of the same genus on the mainland (Olson 1981).
The Noronha skink is "ubiquitous
and incredibly abundant" (Carleton and Olson 1999), occurring across a
broad spectrum of habitats from "rocky seashore to insular forest (Silva-Jr.
et al. 2005c)." It is eaten by introduced animals such as cats, rats,
and tegu lizards (Silva-Jr. et al. 2005c). Molecular analysis of the
Noronha skink's DNA shows that its ancestors came from Africa rather than
from South America (Mausfeld et al. 2002).
See Photo 21,
Photo 22.
The Norohna skink is a "very versatile and opportunistic forager" (Sazima
et al. 2005), eating a broad array of foods ranging from "flower nectar to
human leftovers (Silva-Jr. et al. 2005c)." However, plant
material makes up 77% of the food volume it eats (Rocha et al. 2009).
It is not active at night (Rocha et al. 2009).
In spite of its "predominately ground-dwelling habits,"
this lizard is "a skilled climber," and is
frequently seen visiting flowers of the leguminous mulungu tree (Erythrina
veluntina), which it climbs high in the treetops to reach (Sazima et al.
2005, 2009). Since Fernando de Noronha has no natural freshwater supply
during drought periods, the nectar of these flowers may be important to
the skink as a source of water, as well as a source of energetic sugar (Sazima
et al. 2005, 2009).
Throughout the world, relatively few
lizards are known to regularly visit flowers for nectar. Most of these
flower-visiting lizards are found on oceanic islands and they visit the flowers
of herbs and shrubs rather than the flowers of trees as the Noronha skink
does. Thus, both endemic species of reptiles found on Fernando de
Noronha have diverged ecologically from their mainland relatives in ways
that are special and noteworthy.
Sea Turtles
The green turtle (Chelonia mydas) breeds on a
few sandy beaches of the main island (Photo
23). The hawksbill turtle (Eritmochelys
imbricata) also occurs in the waters of the archipelago, but conclusive
evidence of its breeding there has not yet been found (Photo
24).
A coral reef fish, the wrasse (Thalassoma
notonhanum), associates with the green turtle as the latter species
forages for benthic algae (C. Sazima et al. 2004). This opportunistic
fish feeds "on drifting particles turned loose from the bottom by the
turtle's feeding activity (C. Sazima et al. 2004)."
Marine algae grows on the shells of sea
turtles, producing drag and reduced speed. To clean themselves of
algae, sea turtles visit "cleaning stations" on reefs where various species
of herbivorous and omnivorous fishes and shrimps live (C. Sazima et al.
2004; I. Sazima et al. 2004). These fish and shrimps eat not only the algae growing on the
turtle shells, but also molting skin and ectoparasites from the turtles'
head and fins (Losey et al. 1994; C. Sazima et al. 2004, 2010; Grossman et
al. 2006). (Photo
25).
References
Carleton MD, Olson SL (1999) Amerigo Vespucci and the rat of
Fernando de Noronha: a new genus and species of Rodentia (Muridae:
Sigmodontinae) from a volcanic island off Brazil's continental shelf.
American Museum Novitates 3256: 1-59
Grossman A, Sazima C,
Bellini C, Sazima I (2006) Cleaning symbiosis between hawksbill
turtles and reef fishes at Fernando de Noronha Archipelago, off northeast
Brazil. Chelonian Conservation and Biology 5: 284-288
Losey GS, Balazs GH, Privitera LA
(1994) Cleaning symbiosis between the wrasse Thalassoma duprerrey
and the green turtle Chelonia mydas. Copeia 1994: 684-690
Maida M, Ferreira BP (1997) Coral reefs of Brazil: an
overview. Proceedings of the 8th International Coral Reef
Symposium 1: 263-274.
Martínez-Vilalta A, Motis A (1992) Family Ardeidae (Herons).
Pp. 376-429 in Handbook of the Birds of the World, Volume 1. del
Hoyo J, Elliott A, Sargatal J (editors). Lynx Editions, Barcelona
Mausfeld P, Schmitz A, Bohme W, Misof B, Vrcibradic D,
Rocha CFD (2002) Phylogenetic affinities of Mabuya
atlantica Schmidt, 1945, endemic to the Atlantic Ocean archipelago of
Fernando de Noronha (Brazil): Necessity of partitioning the genus
Mabuya Fitzinger, 1826 (Scincidae: Lygosominae). Zoologischer
Anzeiger 241: 281-293
Nacinovic JB, Teixeira DM (1989) As aves de Fernando de
Noronha: uma lista sistemática anotada. Revista Brasileira de
Biologia 49: 709-729
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