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THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123. No. 2. June 2011 
l Brood patch or cloacal protuberance —*— Molt 
FIG. 2. Shrike-like Tanager adults captured with brood 
patches or cloacal protuberance and molting at Estagao 
Ecologica de Aguas Emendadas, Brazil, from 2003 to 2006. 
March was not included as no adults were captured. 
and late in 2004 with smaller differences in the 
other years (INMET 2006). This flexibility in nest 
initiation timing allows the species to cope with 
climatic unpredictability and, perhaps, avoid 
nesting in periods of low food abundance. 
Precipitation is known to affect the phenology of 
fruits (Batalha and Mantovani 2000, Batalha and 
Martins 2004) and insects (Diniz and Morais 
1997, Pinheiro et al. 2002) in the Cerrado. 
The breeding period (—13 weeks) is short, 
compared to that of tropical forest birds (reviewed 
by Stutchbury and Morton 2001). The finding of 
some birds with brood patches in January suggests 
Time (days) 
FIG. 3. Nestling period of the Shrike-like Tanager at 
ts * a ( g° Ecologica de Aguas Emendadas, Brazil, from 2003 
to 2006. 
□ 1 egg ■ 2 eggs ■ 3 eggs 
2003 2004 2005 2006 
Years 
FIG. 4. Clutch size (n = 112) of Shrike-like Tanagers 
at Estagao Ecoldgica de Aguas Emendadas, Brazil, from 
2003 to 2006. 
the breeding season may end later than December 
in some years. This short breeding season is 
similar to that for birds breeding in the Cerrado 
(Marini and Duraes 2001; Lopes and Marini 
2005a; Medeiros and Marini 2007; Marini et al. 
2009a, b; Rodrigues 2009; Santos and Marini 
2010). Despite the short breeding season, Shrike¬ 
like Tanager females usually attempted to nest 
more than once in the same breeding season, and 
had high adult survival and low fecundity (Duca 
2007). Tropical birds have long breeding seasons 
compared to temperate species (reviewed by 
Stutchbury and Morton 2001). This does not 
apply in several highly seasonal tropical environ¬ 
ments, such as the cerrado, pantanal wetlands 
(Pinho 2005). and caatinga dry forests (CD, pers. 
obs.). Harsh climatic (e.g., prolonged dry periods 
in the cerrado or caatinga) or environmental (e.g- 
flooding in the pantanal) conditions may last at 
least 4 months and constrain the time available for 
breeding and molt in a similar context as in 
temperate regions. 
Incubation and Nestling Periods .—The incuba¬ 
tion period of the Shrike-like Tanager was ~15~ 
30% shorter than that (15-17 days) reported in 
another area 40 km from our study site (Alves and 
Cavalcanti 1990). This difference in the incuba¬ 
tion period might be explained by methodological 
or year differences or small sample sizes. The 
incubation period we documented is similar lo 
that reported for the Lesser Elaenia ( Elaenio 
chiriquebsis ) (13.4 days) (Medeiros and Marini 
2007) and Black-throated Saltator (14 days) 
