The Wilson Journal of Ornithology 123(4):726-733, 2011 
SIZE DIMORPHISM, JUVENAL PLUMAGE, AND TIMING OF 
BREEDING OF THE HYACINTH VISORBEARER 
(.AUGASTES SCUTATUS) 
LICLEIA DA CRUZ RODRIGUES' 3 AND MARCOS RODRIGUES' 
ABSTRACT—The Hyacinth Visorbearer (Augustes soutanes) is a poorly known hummingbird endemic to the Cadciado 
Espinha^o in southeastern Brazil and is classified as near threatened w ith global extinction. We verified size dimorphism of 
males and females, describe the plumage patterns of juveniles, and detail the reproductive period of this species in Serrado 
Cip6 National Park within the municipality of Monro do Pilar in the State of Minas Gerais. Brazil during August 2007 to 
July 2009. Adult males were significantly larger than adult females in all measurements assessed. Variables that best 
differentiate males and females are body mass, total body length, occipital width, bill length, and wing chord. We 
demonstrated that it may be possible to assign gender of the majority of young of this species, based primarily on the color 
of the side of the neck and the tract of feathers that circles the visor. There is some indication of a greater concentration ol 
reproductive effort during the dry season, when more juveniles and active nests were recorded. However, we captured 
fledged young in January, February, and March supporting a breeding period throughout the year for the Hyacinth 
Visorbearer. This suggests rainfall in the region is the most influential factor in timing of breeding of this species. Received 
19 February 2011. Accepted 28 June 20/1. 
The Hyacinth Visorbearer (Augastes scutatus) 
is endemic to the Cadeia do Espinhayo in 
southeastern Brazil with a distribution restricted 
to the south-central portion of the highlands. The 
species occurs only at altitudes >1.000 m along 
the southern part of the range (Iron Quadrangle = 
Quadrilatero Ferrifero) in the Serra do Cipd to the 
Serra do Pau D'Arco in northern Minas Gerais, 
almost to the southern border of Bahia (Vascon- 
celos 2008). The Hyacinth Visorbearer appears to 
be sensitive to changes in habitat, as it has not 
been observed in disturbed areas of the Cadeia do 
Espinha^o (Vasconcelos 1999). The species’ 
habitat is primarily threatened by destruction of 
large tracts of rocky fields locally known as conga 
(rocky outcrops that are rich in iron oxide) for 
extraction of iron (Jacobi and Carmo 2008). 
Mining activity in these tango areas probably 
led to the local extinction of Hyacinth Visorbearer 
in certain localities of the Iron Quadrangle 
(Vasconcelos 1999. Vasconcelos and Rodrigues 
2010). This species has a highly restricted 
geographical distribution and occurs in habitat 
that is subject to significant anthropogenic 
pressures. Thus, the Hyacinth Visorbearer has 
been classified as near threatened with global 
extinction (BirdLife International 2010). 
The Hyacinth Visorbearer is considered sexu- 
i^D La , t ? 0ra,6r, ° de ° mitolo S ia ' Dcpanamento de Zoologi 
i«A%.^ V « rsidade Fcderal de Min «* Gerais, Caixa Post. 
fl-? 270-90 i. Belo Horizonte. Minas Gerais, Brazil, 
orresponding author; e-mail: licleia@yahoo.com.br 
ally dimorphic, as males are distinguishable from 
females by their more intensely iridescent blue- 
green forehead, chin and throat, and the presence 
of a narrow black band around the visor, except 
on the lower part of the throat. The collar is while 
or pale pink and the sides of the neck, chest, and 
abdomen are iridescent blue and/or violet, varying 
by individual (Fig. I A). The forehead, chin, ana 
throat of females usually have a slight infusion of 
gold coloration, while the feather tract that 
surrounds the visor is dark brown and the sides 
of the neck are blue; there is an infusion of pans 
green and some isolated yellow and violet feathers 
in some individuals. The chest and abdomen are 
predominantly paris green with some specimens 
having isolated feathers in this region that arc 
more brown, blackish-gray and blue (Fig. 1C) 
(Abreu 2006). The intensity of polymorphism of 
the Hyacinth Visorbearer (Abreu 2006). led to 
description of two subspecies: Augastes scutatus 
sourest (Ruschi 1962) and A. scutatus ilseae 
(Grantsau 1988). However. Abreu (2006) demon¬ 
strated that A. scutatus can not be fragmented into 
other taxa and that these subspecies should be 
considered invalid. 
Morphometric data are available only for a 
small number of specimens (Abreu 2006). Size 
dimorphism between males and females was 
previously unknown and both juvenile males and 
females look like adult females (Abreu 2006)- 
They differ slightly in the coloration of the throat, 
chest, and abdomen, which is mostly varying 
shades of brown or gray that are gradually 
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