SHORT COMMUNICATIONS 
175 
FIG. 2. Egg of Sporophila melanogaster. (Photograph 
by Cristiano E. Rovedder). 
yellowish blotches and stripes (Sepia 219 and 
Burnt umber 22 [sensu Smithe 19751), as well as 
smaller spots were generally more concentrated at 
the larger end (Fig. 2). Egg measurements (n = 8) 
were: length = 17.5 ± 0.43 (range = 16.9-18.3) 
and width = 12.2 ± 0.35 min (range = 11.7- 
12.8). Nests had little variability in shape and 
measurements, especially in the internal chamber. 
However, height above the ground was variable 
which could be the result of the need to elevate 
the nest above the water level in the wetlands 
(Table 1). 
DISCUSSION 
Nests of S. melanogaster resemble those of its 
congener S. hypoxantha in shape, structure, and 
measurements (Di Giacomo 2005, Franz and 
Fontana 2010); the two species are sympatric in 
Part ol their breeding ranges and both use similar 
nest-support plants, including Eupatorium poly- 
stachyum and Baccharis capra riifolia (Franz and 
Fontana 2010). However, our data indicated that 
N melanogaster preferred Ludwigia sericea for 
nest sites. Nest construction is by the female, as for 
other species of Sporophila (e.g.. S. leucoptera . 
S. hypoxantha, S. lineola). The number of eggs laid 
per clutch is also similar (Di Giacomo 2005, 
Francisco 2009, Franz and Fontana 2010, Oliveira 
et al. 2010). 
The literature indicates Sporophila mekmogas- 
ter breeds only in wetlands (Machado et al. 1998, 
Bencke ct al. 2003, Machado et al. 2008). despite 
a lack of specific studies on the nesting behavior 
of the species with one exception (Rovedder 
201 I ). However, this species can nest in dry and 
natural portions of steep fields (using Eupatorium 
polystachyutn bushes) near drainages or wetlands 
where use by cattle or people is infrequent. This 
could be an adaptation to loss of wetlands and 
conversion to crops; human stresses, such as live¬ 
stock grazing or agriculture could create inappro¬ 
priate habitats for Black-bellied Seedeaters. 
Nesting-plant species preferences by 5. mela¬ 
nogaster are suggested based on the proportion of 
the first and the second most frequently used 
plant, and also by quantitative studies (Rovedder 
and Fontana in prep.). This knowledge, as well as 
detailed description of the nest and eggs of the 
Black-bellied Seedeater, is important for devel¬ 
opment of new studies on the species’ life history 
to benefit conservation of this threatened endemic 
Brazilian species. 
ACKNOWLEDGMENTS 
We are grateful to 1 I. Boldrini and staff (UFRGS) for 
assistance in identifying plant species; Ismael Franz. Jonas 
Rosoni, Marcio Repenning, and Mariana L. Gongalves for 
field assistance; two anonymous reviewers and C. E. Braun 
for manuscript improvement: the Fundacao Grupo Boti- 
cario de Protegao a Namreza and Neotropical Grassland 
Conservancy for financial support to the project; CNPi] for 
a scholarship to C. E. Rovedder; and the Museu de C iencias 
e Tecnologia da PUCRS for logistical help. 
LITERATURE CITED 
Bencke. G. A., C. S. Fontana. R. A. Dias, G. N. 
Mauricio. and J. K. F. Mahler Jr. 2003. Aves. 
TABLE 1. Measurements (cm) of 48 nests of the Black-bellied Seedeater (Sporophila melanogaster) in Brazil. 
Variables 
Mean 
SD 
Min 
Max 
Largest external diameter 
6.55 
0.57 
5.5 
8 
Smallest external diameter 
6.13 
0.45 
5.3 
7.3 
Largest internal diameter of chamber 
4.55 
0.37 
3.9 
5.5 
Smallest internal diameter of chamber 
4.24 
0.33 
3.5 
5 
Eternal height 
5.14 
0.57 
3.5 
6.8 
Internal height (depth) 
3.34 
0.42 
2.3 
4.1 
Height above ground (« = 54) 
31.5 
10.83 
15 
60 
