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Steatornis caripensis is a gregarious species occurring
in colonies´ occupying large dark caves which are used as daytime
roosts and for breeding. The species is most famous for its use of echolocation
clicks enabling it to perfectly navigate and breed in these pitch-black
caves. This echolocation behavior is shared with Bats (Chiroptera) but
also with two less well known bird species from SE Asia, Aerodramus Swiftlets,
demonstrating an amazing example of convergent evolution from the Old
world to the New world. These Swiftlets are also locally found in dark
caves where immense colonies of sometimes millions can be found using
echolocation to navigate in the pitchblack environment. Steatornis depart
from the caves at dusk to fly long distances to forage gregariously for
fruit, apparently locating aromatic fruit by smell and nonaromatic fruits
such as palms by sight Snow (1962).
Recent
genetic analysis of caprimulgiforms indicates that Steatornis was the
earliest to branch away from all lineages, Brumfield et al (1997) with
its closest affinities thought to be with Nyctibiidae, (Potoos) and Caprimulgidae,
(Nightjars). The distinct rufous plumage and bold white spotting of Steatornis
causes it to bare a striking resemblance to the smaller rufous Potoo,
(Nyctibius bracteatus). Nyctibius bracteatus is however a true insectivore,
inhabiting the Amazonian lowland rainforests of Brazil, eastern Ecuador,
eastern Peru, northwestern Bolivia and Guyana, Ridgely and Greenfield
(2001).
On
the 21 May 1998 at Palmari Lodge, Rio Javarí, Amazonas 4º17´17
S 70º17´33 W the freshly dead remains of an Oilbird were found
by A. Antoine-Feill and R. Schiele along a forest trail through virgin
"terra firme" forest. The carcass remains suggested that it
had been very recently predated. Feather samples were collected and five
feathers were deposited in the Institute Nacional de Pesquisa da Amazonia,
INPA 447 as material evidence for this the first confirmed Brazilian Record.
AW made a direct comparison of these Palmari feathers with two Venezuelan
Steatornis specimens at the Museu Emílio Goeldi in Belém.
MPEG 33147-48 from the Rio Paragua, Sierra Urutari, Bolivar. Confirming
beyond doubt that the feathers did belong to Steatornis and referred to
a primary, two secondaries, one rectricie and a mantle feather. However
due to such few feather specimens it did not allow for a fair detailed
comparison to be made with the highland birds from Venezuela.
Following
the discovery at the Reserva Natural Palmari of the Steatornis
communication with local riberinhos (riverside people) revealed that they
not only new of the presence locally of Steatornis, they also describing
the bird´s plumage, its habits and their unusual characteristic
screaming calls. Further more they informed of how Steatornis are sometimes
killed on river cliffs or from within hollow trees as they roost by day,
later being used as torches by the community at night as they burn well
for long periods. Historically Steatornis nestlings have been collected
by indigenous peoples and cooked to extract a clear odorless oil that
was used mostly for cooking, or in some localities for lamp, oil del Hoyo
et al (1999).
From
adjacent Peru D. Graham (pers comm..) reports a recent observation of
a lone Steatornis. At 21:00 h on 1 January 2002 at Paucarillo Forest Reserve,
Loreto 3º41.28 S 72º11.19 W along the Rio Orosa where DG and
eight other ornithologists observed at close quarters a flying Steatornis.
The bird was observed in flight using a strong spotlight and became disoriented,
where upon it flew towards the light and started to emit strong clicking
sounds while it briefly flew in tight circles. The bird remained flying
in the light beam 10-15 m above the riverbank for about 45 sec before
flying off strongly out of site. This Amazonian Peru locality is some
225 km WNW from the Palmari location and on the south bank of the Amazon.
Sick
(1984) was the first to report on the possibility of Steatornis penetrating
into Brazilian territory from active Steatornis caves he located in 1970
in southern Venezuela close to the Brazilian frontier. Later during the
mid 1980´s several large Steatornis colonies were discovered in
the Venezuelan state of Bolivar on the Brazilian boarder in the state
of Roraima, including a huge colony at Aguapira contained as many as 10.000
birds. Sick (1993) included Steatornis as occurring in northern Brazil
in Roraima for the following reason. The Cerro Urutaní has contained
an active Steatornis colony in the Urutaní caves at 1300 m since
1978, whose end is 228 m away in Brazilian territory, Dickerman and Phelps
Jr (1982). In fact there are no true sight or specimen records prior to
ours confirming Steatornis occurring in Brazil. However it seams very
reasonable to assume that it was only a matter of time before Steatornis
would be confirmed from northern Brazil most probably from the Highlands
of Roraima. We feel confident to state nobody would ever have expected
Steatornis to be first confirmed from the lowlands of western Amazonian
Brazil!
These
two recent Amazonian lowland records from Brazil and Peru of Steatornis
from May and January (well separated months) combined with the comments
of the local riverside community around Reserva Natural Palmari strongly
suggest that this occurrence from the lowlands of Steatornis may well
not be quite as unique as was at first expected.
The
nearest known breeding colony to the Reserva Natural Palmari
in Colombia is about 600 km in direct flight NNW to caves in the Colombian
tablelands, of Vaupés (Olivares 1964, Hilty and Brown 1986). Colonies
in Peru T. Schulenberg (Pers. Comm..) are mostly all from Andean foothills
800-900 km away, however a recent site record from Tahuayo 08º10
S 74º02´W some 600 km away is the closest record bringing Steatornis
east across the Ucayali River. Roca (1994) using radio telemetry in Venezuela
on ten Steatornis recorded to move 240 km in one night to another roosting
cave, proving the theory that Steatornis can cover long distances quickly.
We
suggest further ornithological fieldwork should be carried out in western
Amazonian Brazil and adjacent Loreto Peru aimed at trying to locate Steatornis
and to confirm its status. Clarifying the status of Steatornis in this
lowland region will revile if these two records do in fact involve as
yet an unknown lowland-breeding colony. If a breeding population does
exist however we strongly recommend that new material (both specimens
and tissue samples) should be collected and a through comparison of this
material (both skins and DNA analysis) should be made with the highland
birds. We feel this would be extremely important to evaluate to see if
these lowland forms may possibly, represent a different sub species or
possibly even a new taxa.
Aknowlegments-
We would like to thank T.S. Schulenberg and Devon Graham for sharing their
knowledge and unpublished data on Steatornis. Our sincere thanks go to
María L. Videira at the Museum Emílio Goeldi, Belém
for allowing AW to visit and examine the Steatornis specimens in their
collection. AW would like to thank the wonderful hospitality provided
to him from the staff at Palmari Lodge during his stay. References-
Brumfield R.T., D.L. Swofford, and M.J. Braun, 1997. Evolutionary relationships
among the Potoos (Nyctibiidae) based on isozymes.
Ornithological Monograph No 48. Pp 129-145.
Del
Hoyo, J., Elliot, A. and Sargatal, J 1999. Handbook of the Birds of the
World. Vol 5 Barn-owls to Hummingbirds. Pp 250.
Dickerman,
R.W., and W.H. Phelps, Jr. 1982. An annotated list of the birds of Cerro
Urutaní, on the boarder of Estado Bolivar, Venezuela and Territoria
Roraima, Brazil. American Museum Novitates, No 2732, pp 1-20.
Hilty,
S.L., and W.L. Brown. 1986. A guide to the birds of Colombia. Princeton
Univ., Princeton, New Jersey.
Olivares,
A. 1964. Adiciones a las aves de la Comisaría del Vaupés
(Colombia), II Caldasia 9: Pp 379-393.
Roca,
R.L. 1994. Oilbirds of Venezuela: Ecology and conservation. Nuttall Ornithological
Club 24, Cambridge, Massachusetts. Pp. 83.
Ridgely,
R.S., and P.J. Greenfield. 2001. The Birds of Ecuador. Cornell Univ. Press,
Ithaca, New York.
Sick,
H. 1993. Birds in Brazil: A natural history. Princeton Univ. Press, Princeton,
New Jersey.
Snow,
D.W. 1962. Natural history of the Oilbird Steatornis caripensis in Trinidad
W.I.II. Population, breeding, ecology and food. Zoologica 47: 199-221.
Addresses:
1)
Conjunto Acariqara, Rua Samaumas 214, Manaus 69085-410, Amazonas, Brazil.
E-mail: andrew@birdingbraziltours.com;
2)
Reserva Natural Palmari, Carrera 10 # 93-72 "Palmari" Building,
Bogotá D. C., Colombia. E-Mail: info@palmari.org / palmari@etb.net.co
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