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THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 124. No. 3. Sept ember 2012 
The Yellow-olive Flatbill in Brazil occupies, 
but is not restricted to. threatened habitats such as 
Atlantic Forest fragments and gallery forests of 
the Cerrado, both within highly disturbed biomes. 
Forest fragmentation may affect breeding success 
through increased brood parasitism and nest 
predation, reducing bird numbers in fragmented 
landscapes (Wilcove 1985. Temple and Cary 
1988. Robinson 1989. Marini 1997, Tewksbury 
et al. 2006). The "V ellow-olive Flatbill represents a 
model lor studies addressing the effects of habitat 
fragmentation on nesting success and. ultimately, 
population viability in these fragmented systems 
(e.g.. Duca et al. 2009). 
We describe the nesting biology of the Yellow- 
olive Matbill in Atlantic Forest fragments in 
Minas Gerais. Braz.il. We report morphometric 
measurements ot eggs, nestlings, and nests; nest¬ 
ing seasonality, and duration of breeding cycles 
between 1996 and 2000; and estimated egg fail¬ 
ure, fledgling productivity, and overall survival 
rates for the study period. 
METHODS 
Study Area. This study was conducted in the 
protected areas of the Barreiro and Mutuca 
reserves, owned by Minas Gerais Water Company 
(COPASA MG). The reserve system is in the 
municipalities of Nova Lima and Belo Horizonte 
Minas Gerais State. Brazil (20 02'-20 00' S. 42 
59'-44 00' W). We searched for and monitored 
nests in one 50-ha and one 200-ha forest fragment 
at Barreiro Reserve each year from 1996 to 2000 
during July through January. We searched for and 
monitored nests in 1996 in a 300-ha forest frag¬ 
ment at Mutuca Reserve. Both reserves contain a 
combination ol dry, semi-deciduous, and gallery 
forests which are secondary growth with succes- 
sional stages varying between 90 and 150 years 
(CETEC 199.3). These three forest fragments 
represent the only forest habitat available in the 
reserves, and they were included in the study. 
Trails within the reserves were chosen randomly 
and we also searched for and monitored nests 
along the main river courses within the forests. 
This region is subject to warm, rainy summers and 
cool, dry' winters with most precipitation between 
November and March. Annual precipitation varied 
studv Th ( ^ IO mm (,997) durin £ °ur 
; u'T""" teni P era,ure recorded was 9 C 
and 1 9 )7) and the maximum was 37 C (1 997 ) 
(Mutuca and Fechos climatic stations, managed by 
MBR-Minerafocs Brasileiras Reunidas and CO¬ 
PASA MG, respectively). 
/Vest Monitoring. Nest searches began in Juh 
and were conducted systematically every 3-5 daw 
along rivers, roadbeds, and in the forest interior. 
We marked locations of nests with pink plastic 
Hugging 5-10 m from the nest and checked nest 
status every 3-5 days. We counted eggs and/or 
nestlings during each visit, weighed them with a 
0.1 or ().2-g spring dynamometer, and measured 
them with 0.05-mm precision calipers. We 
measured nests with calipers after nests were 
considered inactive. 
We considered a nest successful when at least 
one nestling left the nest. Monitored nests found 
empty alter the maximum known age for nestlings 
to Hedge, and did not have signs of structural 
damage caused by predation were considered 
successlul. These nests were successful at the 
prior visit and lacked common evidence of pre¬ 
dation (leathers, partial nest destruction), and wc 
assumed they produced fledglings. Nests found 
empty prior to predicted fledge dates, as well as 
those with evidence of predation such as feathers 
or damage to the nest structure, were considered 
depredated. Nests w'ere considered abandoned 
when eggs remained intact in the nest for longer 
than the incubation period. Nests with dead 
nestlings without any signs of aggression were 
also considered abandoned. Nests abandoned 
belore eggs were laid were not considered in 
analyses of reproductive success. 
Nestling Growth and Productivity. —Growth 
curves lor nestlings were plotted using logistic 
regression (Ricklefs 1976. Zullingeret al. 1984): 
M(t) — A(e-k " " + l)~f, where A = asymptote 
(mass. wing, tail, tarsus or bill), t = age (days), k 
= growth rate constant (days -1 ), and / = age al 
the inflection poim (days). We calculated egg 
volumes using Hoyt's (1979) equation: volume = 
0.51 X (length) X (breadth)-. We divided the total 
number of nestlings by the total number of egg> 
laid to calculate hatching rate. Morphological 
parameters ot eggs and fledglings are presented as 
means t. SB. We estimated productivity from the 
ratio between total number of fledglings and total 
number of broods. 
Statistical Analyses. —We followed Mayfield 
(1961. 1975) and Manolis et al. (2000). Alterna¬ 
tive nest survivorship estimation methods have 
recently been proposed, but we used the Mayfield 
method because it has proven as useful as other 
indices when sample siz.es are large (n > 25) and 
