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ON 24(1) 95
SHORT COMMUNICATIONS
ORNITOLOGIA NEOTROPICAL 24: 95–99, 2013
© The Neotropical Ornithological Society
A NOVEL HOST OF THE SHINY COWBIRD (MOLOTHRUS
BONARIENSIS): THE NEAR-THREATENED PALE-THROATED
SERRA-FINCH (EMBERNAGRA LONGICAUDA)
Lilian Mariana Costa
Programa de Pós-Graduação em Ecologia, Conservação e Manejo de Vida Silvestre, ICB,
Universidade Federal de Minas Gerais, Caixa Postal 486, Belo Horizonte, Minas Gerais,
31270-901, Brazil. E-mail: [email protected]
Um novo hospedeiro do parasita de ninho Vira-bosta (Molothrus bonariensis): o quase-ameaçado
Rabo-mole-da-serra (Embernagra longicauda).
Key words: Pale-throated Serra-Finch, Embernagra longicauda, Shiny Cowbird, Molothrus bonariensis,
Brazil, breeding biology, brood parasitism, cowbirds, fledgling, interspecific nest parasitism.
INTRODUCTION
The Pale-throated Serra-Finch (Embernagra
longicauda) is a poorly-known bird endemic to
the mountain tops of eastern Brazil, being
nearly confined to the Espinhaço Range in
the states of Minas Gerais and Bahia (Vasconcelos 2008). It is listed as Near Threatened by
BirdLife International (2012) due to habitat
loss within its restricted and naturally fragmented distribution range.
The natural history of the Pale-throated
Serra-Finch is still poorly known. The most
detailed study of the species is about its territory size and habitat selection (Freitas & Rodrigues 2012). Recent observations have also
been made on the species’ diet, behavior, and
other natural history aspects (Freitas & Rodrigues 2008, 2011; Hoffmann et al. 2009).
The reproductive biology of the Pale-throated
Serra-Finch - breeding season, nest, egg, nestling and juvenile descriptions - are generally
known (Mattos & Sick 1985, Vasconcelos &
Silva 2003, Freitas & Rodrigues 2008, Freitas
et al. 2009, Hoffmann et al. 2009, Rodrigues et
al. 2009). More than 10 breeding attempts
(nests of family groups) can be gathered from
those studies; nevertheless, none have mentioned brood parasitism in this species. Here I
document the Pale-throated Serra-Finch as an
effective host of the Shiny Cowbird (Molothrus
bonariensis), an obligate brood parasite.
METHODS
The observation was conducted opportunistically in ‘Alto do Palácio’ (19°15’37”S,
43°31’57”W; c. 1360 m a.s.l.), a region in the
northern part of Serra do Cipó National Park,
municipality of Morro do Pilar, state of Minas
95
COSTA
Gerais, southeastern Brazil. Alto do Palácio
lies near the top in eastern slope of the Serra
do Cipó mountain, in the southern portion of
the Espinhaço Range (see Rodrigues et al.
2011 and Freitas & Rodrigues 2012 for a
detailed description of the area).
RESULTS AND DISCUSSION
On 18 January 2012, I found a Shiny Cowbird
fledgling perched in a ‘candeia’ tree (Eremanthus sp., Asteraceae) growing in the sparse
vegetation of campos rupestres (rocky grasslands) habitat. The parasite fledgling was in a
dull blackish plumage, matching the ‘melanogyna’ morph (Fraga 2011). After a few
minutes, an adult Pale-throated Serra-Finch
approached and fed the parasite (Fig. 1). The
finch foraged in the denser cover of low
bushes surrounding the area, while the cowbird stayed for most time perched in visible
higher bushes or small trees, sometimes following the host. I observed the birds by about
40 min, during which no other adult Palethroated Serra-Finch nor fledgling was
detected.
January is the end of the breeding season
of the Pale-throated Serra-Finch, when fledglings are still observed (Freitas & Rodrigues
2008, Freitas et al. 2009, Hoffmann et al.
2009). The Shiny Cowbird is recorded at
Serra do Cipó highlands mostly from August
to December (Costa & Rodrigues 2012),
which overlaps the Pale-throated SerraFinch’s breeding season.
The Pale-throated Serra-Finch has not
been listed among the target host species of
the Shiny Cowbird (Lowther 2012), although
its status as a host of this parasitic bird was
previously suspected by Collar et al. (1992).
The observation reported here strongly suggests that the species is a true or effective
host, i.e., able to rear parasitic young until
independence (Lowther 2012). The congeneric Great Serra-Finch (Embernagra platensis)
96
and the phylogenetically related Wedge-tailed
Grass-Finch (Emberizoides herbicola) have also
been reported as victims (sensu Lowther 2012)
of the Shiny Cowbird in Paraguay and Argentina (Friedmann 1931, Di Giacomo 2005,
Lowther 2012).
A recent compilation listed more than 260
species as victims of the Shiny Cowbird with
97 species known to be true hosts along the
range of this obligate brood parasite (Lowther
2012).
In Brazil, there has been limited information about the hosts of the Shiny Cowbird
(see Sick 1958, 1997; Cavalcanti & Pimentel
1988). Therefore, to help our understanding,
it is essential that brood parasitism be studied
in Brazil and that even simple observations
reporting new hosts be properly published
(e.g., Maurício 2011).
Although based on a single observation,
this report indicates that brood parasitism is
one potential threat for the Pale-throated
Serra-Finch. In Serra do Cipó highlands,
another bird also endemic to the mountain
tops and near-threatened, the Cipo Canastero
(Asthenes luizae), is a recognized host of Shiny
Cowbird (Gomes & Rodrigues 2010) which is
intensely parasitized also by the ‘melanogyna’
morph of M. bonariensis (Costa & Freitas in
prep.; see Costa 2011). This is the only information on brood parasitism for the region.
In ‘Alto do Palácio,’ where the Pale-throated
Serra-Finch is common (Rodrigues et al.
2011), 17 mated pairs were studied for
one year, but only one nest and few family
groups were observed (Freitas & Rodrigues
2008, 2012; Freitas et al. 2009, Rodrigues et al.
2009). In Serra do Rola Moça State Park,
municipality of Nova Lima, Minas Gerais,
two of three nests of the Pale-throated SerraFinch were successful (Hoffmann et al. 2009).
The paucity of recorded breeding attempts
prevents additional inference on breeding
success or parasitism frequency of this
species.
SHORT COMMUNICATIONS
FIG. 1. Shiny Cowbird (Molothrus bonariensis) fledgling being fed by an adult Pale-throated Serra-Finch
(Embernagra longicauda), at Serra do Cipó National Park, southeastern Brazil.
Further studies could discover if the Palethroated Serra-Finch is a casual host or if it is
regularly parasitized, and determine the
effects of parasitism on the population
dynamics of this species in order to improve
the conservation needs of this species.
ACKNOWLEDGMENTS
I am especially grateful to Elisa P. Mesquita
for help in fieldwork. I thank CAPES and
Fundação O Boticário de Proteção à
Natureza for financial support during the
study, and the staff of ICMBio/IBAMA for
permitting research in Serra do Cipó National
Park. Rosendo M. Fraga, Peter E. Lowther,
Guilherme H. S. Freitas, and anonymous
reviewers provided helpful suggestions that
improved the manuscript.
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SHORT COMMUNICATIONS
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Accepted 8 April 2013.
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