The Wilson Journal of Ornithology 123(2):259-265, 2011 
VARIATION IN BREEDING OF THE SHRIKE-LIKE TANAGER IN 
CENTRAL BRAZIL 
CHARLES DUCA 1,3,4 AND MIGUEL A. MARINI 2 
ABSTRACT.—The Shrike-like Tanager {Neothraupis fasciata) is a Cerrado bird considered as near threatened. Its life 
history is poorly known, especially its reproduction. We monitored reproduction during four breeding seasons (2003-2006) 
with 120 nests in a protected area in central Brazil. Nesting began at the end of the dry season and start of the rainy season. 
The incubation (13.0 days) and nestling (11.7 days) periods were shorter than for most neotropical birds, but similar to some 
other tanagers. Clutch size (2-3 eggs) was similar to most tropical birds. However, clutch size increased and nest initiation 
date advanced ~30 days in a year of early precipitation compared to 3 other years with regular or late precipitation. The 
Shrike-like Tanager had breeding flexibility and ability to adapt to changes in temporal precipitation patterns. Received 23 
July 2010. Accepted 21 December 2010. 
Understanding population dynamics is of fun¬ 
damental importance in ecology, evolution, and 
conservation, especially in regions with habitat 
loss or other anthropogenic degradation. The 
Shrike-like Tanager (Neothraupis fasciata), the 
only species in this genus, occurs in the Cerrado 
(neotropical savanna) and is classified as near 
threatened (IUCN 2009). It is a generalist forager 
(Alves 1991) occurring at altitudes from 500 to 
1.100 m (Ridgely and Tudor 1994). It constructs a 
basket-shaped nest <1 m above ground (Alves 
and Cavalcanti 1990) and often is a sentinel in 
mixed species flocks (Alves 1990. Ragusa-Neto 
2000). It is monogamous, forms flocks of up to six 
individuals and is a cooperative breeder (Alves 
1990). Clutch size is usually two or three (Alves 
and Cavalcanti 1990). It is one of the few of the 
>800 cerrado birds whose breeding has been 
studied (Marini 1992; Lopes and Marini 2005a; 
Francisco 2006; Carvalho et al. 2007; Medeiros 
and Marini 2007; Marini et al. 2009a, b). 
Breeding requires additional energy (over non¬ 
breeding metabolic needs) and includes risks that 
influence future survival (Rieklefs 1990). Clutch 
and egg size, and duration of incubation and 
nestling periods contribute to individual fitness 
and are subject to natural selection (Lack 1947. 
Rieklefs 2000a). Little is known about the natural 
history and breeding biology of most neotropical 
1 (^.s-graduafao em Ecologia, Universidade de Brasilia, 
Brasilia, DF 70910-900, Brazil. 
Dcpanamcnto de Zoologia, Universidade de Brasilia. 
Brasilia, DF 70910-900. Brazil. 
Current address: Centro UniversitArio Vila Velha. 
L'nidade AcadSmicu II - Cifincias Bioldgicas, Rua Comis- 
Si frio Jose Dantas de Mello 21 - Boa Vista, 29102-770. Vila 
'•'elha, Espirito Santo, Brazil. 
Corresponding author; e-mail: cduca@uvv.br 
birds (Mason 1985, Martin 1996), especially those 
species endemic to restricted areas. Even less is 
known about the flexibility of tropical birds to 
changes in temporal climatic patterns (Stutchbury 
and Morton 2001) and global climatic conditions 
(Dunn 2006). Our objectives were to; (1) examine 
the timing of breeding and nesting cycle of the 
Shrike-like Tanager, and (2) learn whether these 
breeding parameters are flexible over time. 
METHODS 
Study Area.—We studied Shrike-like Tanagers 
in a 10,547-ha protected area (Esta^ao Ecologica 
dc Aguas Emendadas) (ESECAE) (15° 29' to 
15 36' S. 47° 31' to AT AY W) in the Distrito 
Federal, Brazil. The protected area includes 
—6,000 ha of suitable Shrike-like Tanager habitat 
(Duca 2007). ESECAE is one of the most 
important protected areas in central Brazil with 
287 bird species (Bagno 1998) or 35% of the total 
species known for the Cerrado hiome (Silva 
1995). ESECAE is an isolated protected area with 
most nearby and surrounding areas now occupied 
by agriculture or housing. The local vegetation is 
a mosaic, ranging front grassland to dense and 
closed woodland, and gallery forests. The climate 
is markedly seasonal with the rainy season from 
September to April, and the remainder of the year 
is exceptionally dry (Niroer 1979). Details on the 
amount of monthly rain during this study (2003- 
2006) are available in Duca (2007). Biological 
details of ESECAE are described by Silva and 
Felfili (1996) and Marirtho-Filho et al. (1998). 
Urban areas and agricultural activities, and 
increased fire risk, are near ESECAE (SEMARH 
2004). 
Shrike-like Tangers were studied mostly in 
100 ha (1 X 1 km) in the interior (>1 km from 
259 
