Occurrence of the Brazilian Merganser (Mergus octosetaceus) in the

Occurrence of the Brazilian Merganser (Mergus octosetaceus ) in
the Southern Border of the Espinhaço Range, Minas Gerais, Brazil
GABRIEL ARVELINO DE PAULA1, MARCONI CAMPOS CERQUEIRA JÚNIOR1 AND RÔMULO RIBON1,2
1
Laboratório de Ornitologia, Departamento de Ciências Biológicas, Instituto de Ciências Exatas Biológicas,
Universidade Federal de Ouro Preto, CEP 35400-000, Ouro Preto, Minas Gerais, Brazil
2
Current address: Museu de Zoologia João Moojen, Departamento de Biologia Animal,
Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil, CEP 36570-000
Corresponding author; Internet: [email protected]
Abstract.—We report a new locality for the Brazilian Merganser (Mergus octosetaceus), a critically endangered species from Southern and Central South America. The species’ range is considerably extended to the East, and a new
habitat and basin used by the species are given. The species was found near the city of Ouro Preto, Minas Gerais
State, Brazil, located in a transition zone between the Cerrado and the Atlantic Forest biomes. Our finding improve
a little bit the hope for the conservation of the species but more detailed studies to determine if there is a resident
population, or if we recorded a vagrant bird, are necessary. Received 11 June 2007, accepted 10 November 2007.
Key words.—conservation, Doce River, Espinhaço range, Merganser, Mergus octosetaceus, Ouro Preto, threatened
species.
Waterbirds 31(2): 289-293, 2008
The Brazilian Merganser (Mergus octosetaceus) is a critically endangered bird (BirdLife
International 2007) inhabiting clear water
and rapids, deeper than one m and more
than three m wide, where exposed rocks are
used for roosting (Silveira and Bartman
2001). Most of the time the birds feed in
clear water, weak flow natural pools (Silveira
and Bartman 2001), with submersed microphytes and riverine forests (Pineschi and Yamashita 2000). Territory is estimated to nine
km of linear river, and can be related to food
and nest sites availability (Silveira and Bartman 2001), as trunk holes in gallery forests
trees (Partridge 1956) and crevices in rocks,
at regions dominated by open grassy fields or
rupestrian fields (Lamas and Santos 2004).
Shyness and ability to detect intruders make
behavioral observations of the Brazilian Merganser a difficult task and its biology poorly
known (Silveira and Bartman 2001).
Brazilian Merganser have been recorded
in a couple of localities in Brazil: upper Tocantins river in Nova Roma county (Sick
1997), Chapada dos Veadeiros National Park
(Yamashita and Valle 1990), and Emas National Park (Collar et al. 1992), in Goiás State,
and Jalapão State Park (Braz et al. 2003), in
Tocantins State. A small population was
found in the Tibagi river, Paraná State (Anjos
et al. 1997), and there are records of 3-4 indi-
viduals in southwestern Bahia State (Pineschi
and Yamashita 2000). In Minas Gerais State
the species was observed by G.T. Mattos in
the Salitre creek, near Salitre de Minas county, in 1973 (Sick 1997), although currently
the species is suspected to be confined to the
Serra da Canastra National Park and neighborhoods (Andrade 1998). Old records are
from Mato Grosso do Sul, Rio de Janeiro, São
Paulo, and Santa Catarina states, where it is
believed to be extinct (Stattersfield 2000).
The species is also found in the upper Parana
River, Paraguay, with the last record in 1984
by N. López (Hughes et al. 2006). In Argentina the species is restricted to the Misiones
Province (Partridge1956), where it is in the
brink of extinction (Benstead et al. 1994;
Hughes et al. 2006).
METHODS
Observations were made with binoculars Tasco 8 × 21
mm and Zenit 10 × 50 mm. Calls were tape-recorded with
a Sony TCM 5000 EV and a Sennheiser ME 66 microphone, and housed at the Arquivo Sonoro Elias Coelho
(ASEC, Universidade Federal do Rio de Janeiro). Photographs and a movie were also used for documentation
(Canon EOS-500; 75-300 mm lenses). From April to August 2004 four visits a week were made to the study area.
Study Area
Observations were made at Itacolomi State Park
(IEP) (20°22’30”-20°30’00”S, 43°32’30”-43°22’30”W),
289
290
WATERBIRDS
roughly 100 km from Belo Horizonte city, Minas Gerais
State. The park extends through Ouro Preto and Mariana counties, protecting most of the Serra do Itacolomi,
the southernmost branch of the Espinhaço Range (Messias et al. 1997).
The IEP covers some 7,000 ha and its vegetation is
classified as lower-montane pluvial forest, having also riparian pluvial forest and rupestrian fields (Messias et al.
1997). The park is situated in the Rio Gualaxo basin, a
tributary of Doce River. The main watercourses are Prazeres and Domingas creeks and the Belchior stream. The
“da Curva” (20°25’85”S, 43°30’54”W), is an artificial lagoon, at 1,225 m a.s.l., with two m of maximum depth,
and scattered trees bordering it. It is near the headquarters of the park and is supplied by the Manso creek,
which is no more than one m wide and is surrounded by
closed, low vegetation.
RESULTS
Although there is one record in 1819 for
the das Velhas river (Collar et al. 1992), near
Ouro Preto, there is no indication of the exact municipality. The first sighting in this
study of the Brazilian Merganser occurred in
24 April 2004, at 13.00 h, when a single individual was observed in the da Curva lagoon.
The record extends the species range 300
km to the east, from the site where the better
known population (and maybe the largest
one) of the Brazilian Merganser still remains—the Serra da Canastra National Park
(SCNP). In 21 May the bird was photographed, and some behavioral observations
were made. The calls were tape-recorded in
19-23 June. The same individual was observed until August of the same year. In four
of the 80 visits to the lagoon the bird was not
seen or heard.
While feeding, the bird in IEP showed
the same behavior described by Bartmann
(1988) for the birds in the SCNP—submerging of the head followed, or not, by diving.
The bird at IEP spent most of the time resting and preening over a partially submerged
trunk. When played back the bird responded promptly in an aggressive way, approaching until one m from the authors. During
these episodes the bird stretched its neck,
lifted its tail and vocalized intensively, as describe by Silveira and Bartmann (2001).
As described for other regions, the bird
at IEP was extremely keen in detecting the
human approaching, even over long distances (Braz et al. 2003). When frightened, the
individual did not fly, but only called briefly
and moved away, swimming to the opposite
side of the lagoon. The literature describes
shiner birds from other regions, as they fly
immediately after detecting human presence (Partridge 1956; Yamashita and Valle
1990; Silveira and Bartmann 2001). The
specimen at IEP often fed on small fish (of
about ten cm of total length) which are
quickly swallowed.
The duck at IEP had slight morphological differences, compared with individuals
from other regions, as it had a mandible
marked smaller than the maxilla, and had a
well visible gap in the feathers of the top of
the head (Fig. 1). Besides morphology, the
shyer behavior and habitat used were very
different, when compared to birds at SCNP
(M.C.C., Jr. and G.A.P., pers. obs.). It is not
possible to precise why the beak and crown
were defective, but the injury could have
been occurred due to a predator attack (wild
animals such as otter, or feral dogs which are
common at IEP), or even human captivity.
Genetic problems could also be the cause of
the morphological differences, but parsimony would be in favor of the previous explanations. The specimen was recognized as a
male, judging for its characteristic call (L. F.
Silveira, com. pess.).
In July 2004 the individual changed resting sites too often. It was also more secretive
than in the previous months, hiding more
frequently in the vegetated bank. These
changes coincided with the land removing
and car traffic due to the construction of a
Figure 1. Male of Brazilian Merganser (Mergus octosetaceus) at Itacolomi State Park. Note the gap in the crown
and the marked smaller mandible (I. R. Lamas).
M. OCTOSETACEUS RANGE EXTENSION
camping area near the lagoon, with increasing tourist numbers, and frequent visits of an
otter (Lontra longicaudis) in the lagoon.
The lagoon where the Brazilian Merganser was found is quite different from those
given by the literature as the only habitat
where the species is found (rapids of clear water rivers, near headwaters) (Yamashita and
Valle 1990, Stattersfield and Capper 2000).
The lagoon is formed by a straight (0.5-1 m
wide), shallow (0.1-0.5 m) and calm creek,
and has a muddy bed. These characteristics
strongly contrasts with the rocky beds of the
watercourses of the SCNP (I. R. Lamas, pers.
comm.), and those from the other sites
where the species have been found. However,
the lagoon is an exception to the rule as
there are some watercourses, in and around
IEP, whose characteristics matches perfectly
those of typical Brazilian Merganser habitat.
Additionally this is the first time the species is
recorded at the Doce River basin, which has
approximately 853 km from its head to
mouth, and could be searched for the merganser, at least near its head.
There is no information of past records of
the Brazilian Merganser at Ouro Preto. However, it is likely that the species could have occurred in the region before and, at least, in
the beginning of the great gold exploration
of the region, in the end of the 18th and beginning of the 19th centuries, when approximately 1/3 of the Portuguese population
moved to Brazil (Brant 2004). The intense
mining that took place by that time lead to a
picture of rivers and land degradation that
shocked travelers and collectors that visited
the region in the early 1800s (Saint Hilaire
1975). If mining 200 years ago was the cause
of the disappearance of the Brazilian Merganser by that time is a matter of speculation as
no skin, drawing or report was left by the
many collectors that have, obligatorily, passed
through Ouro Preto when going to the, then,
almost totally unknown Brazilian inlands. Alternatively, the region would maintain a
relictual population until the present, and
the individual of IEP could be a member of it.
A third possibility is that the bird could be a
vagrant from some far and resident population, such as that of the SCNP.
291
Figure 2. Recent (last 20 years) and historical records of
the Brazilian Merganser (Mergus octosetaceus). Itacolomi
State Park, where we found the individual in Figure 1, is
marked by a flag. Numbers indicate rivers or parks.
Countries and years of records are as follows: Brazil: 1)
Novo river (2002), 2) Jalapão State Park (2002), 3)
Grande river (1999), 4) Correntina and Arrojado rivers
(1999), 5) Corrente river (1999), 6) Formoso and
Itaguari rivers (1999), 7) das Pedras river (2003), 8)
Chapada dos Veadeiros National Park (2004), 9) Emas
Natinal Park (1990), 10) Salitre creek (1973), 11) Serra
da Canastra National Park (2006), 12) Itacolomi State
Park (2004), 13) Rio de Janeiro – no river specified
(1816), 14) Paranapanema river (1903), 15-16) Tibagi
river (2001), 17) Itararé river (1820), 18) Ivaí river
(1926), 28) Itajaí (1827); Argentina: 20) Iguazú river
(1978), 21) Uruguai and Uruzu rivers (1988/2002), 22)
Piray Guazu river (1995), 23) Piray Mini river (1993),
25) Guaruhape and Paranay Guazu rivers (1982/1984),
26) Mandarinas and Victória rivers (1953/1969), 27) Yabebirí river (1912); Paraguay: 19) Paraná river (1891),
24) Carapá river (1984). Letters indicate Brazilian
states: RS = Rio Grande do Sul, SC = Santa Catarina, PR
= Paraná, SP = São Paulo, MG = Minas Gerais, RJ = Rio
de Janeiro, MS = Mato Grosso do Sul, MT = Mato Grosso, Go = Goiás, TO = Tocantins, BA = Bahia, DF = Distrito Federal. Data from Hughes et al. (2006).
The initial tolerance of the Merganser at
IEP to humans and vehicles have not been
described before in the literature which always highlights its secretive habits. We can
not precise the cause of the behavioral
292
WATERBIRDS
change in July 2004 as at least three probable
disturbances have happened that month.
However, all of them, summed, could have
had some influence in the shiny behavior
and latter disappearance of the bird.
DISCUSSION
Our record of the Brazilian Merganser at
Ouro Preto reinforces the importance of the
Espinhaço range to the conservation of the
Neotropical avifauna, which have other Brazilian endemic and near-threatened species
such as the Hyacinth Visorbearer (Augastes
scutatus) (Sick 1997). A priority imposed by
our discovery was the search for other birds
in and out the IEP, to determine if there was
a resident population of the Brazilian Merganser. From September 2004 to September
2006 we conducted play-back surveys in eleven watercourses in Acuruí, Itabirito, Mariana, Ouro Branco and Ouro Preto, and conducted interviews with locals. During 49
field-days 134 points were sampled (approximately one km right from the neigbor, when
in the same watercourse), covering near 160
km of small rivers and creeks (detailed data
available from the authors). No additional
individual of the Brazilian Merganser was
seen but we obtained two strong independent reports from the same family at Conceição river, among 82 interviews with locals.
According to them, two mergansers used to
appear in the early morning or near the sunset in a small, dark water pond (20 m2) used
as fisheries, 50 m from the river. After four
visits to the area we did not see the birds but
the general landscape fits well those where
the Brazilian Merganser have been found in
other sites and more effort should be made
to try to confirm these individuals.
If more individuals have to be found in
the region, the implementation of an educational program targeting the Brazilian Merganser and its habitats would be important.
However, priority should be given to a rigorous control of mining activities that abound
in the region and are already in course, or
those planned to be implemented in the
near future. That priority is based in the fact
that, although with a relatively efficient en-
forcement of environmental regulations,
some mining companies discharge large
amounts of effluents in clear water rivers,
leaving their water muddy by several days.
These action can have important impact upon the few, if existent, individuals of the Brazilian Merganser in the region.
Although the bird seen by us could be a
vagrant, the landscape in our study area, and
the historical record in the Das Velhas river,
lead us to believe that it could have been a
resident population in Ouro Preto region in
the past. In fact, the region was the most degraded by gold mining during the XVII and
XVIII centuries (Dean 1996) and a strong
impact to mergansers could have been imposed even as early as 200 years ago.
Specifically at IEP, access to the camping
area should be strongly controlled and be
made only by the road in the west margin of
the Curva lagoon, that is more forested, allowing observation by tourists while trying
not to interfering in the roosting and resting
site, near the opposite margin.
ACKNOWLEDGMENTS
We are grateful to Fundação O Boticário de Proteção à Natureza (Project 0665_20051), Instituto Estadual de Florestas de Minas Gerais (IEF) and Arquivo
Sonoro Elias Coelho (ASEC-UFRJ). Some equipment
was made available from Birder’s Exchange Program of
the American Birding Association. Thanks to Alberto
Vieira (manager of the IEP), Juarez Távora, André L.
Rochelle, Osiel Magalhães, Lívia V. Lins, Ivana R. Lamas, and Luís F. Silveira by their support, as well to our
parents (M.C.C., Jr., G.A.P.) for financial and moral support. We appreciate the improvements in English usage
made by Jim Armacost through the Association of Field
Ornithologists’ program of editorial assistance. P. F. Develey and an anonymous reviewer made important contributions to the text.
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