Anciaes et al • NESTING OF YELLOW-OLIVE FLATBILLS 
549 
TABLE 1 Nesting parameters of monitored nests of Yellow-olive Flatbills during .lie incubation and nestling phases 
and over the entire nesting period. Survival probability was estimated by .he Mayfield method. Values tor datly survival 
plabTmy of aurvival through phase (PSP,, and standard deviu.ions are used ,o compare 
survivorship between phases. 
Nest pture or comem 
Momiored nests 
or cement 
Exposure men. eggs, 
nesilings-davs) 
Duration (days) 
Lost nests 
or content 
DSP ± SD 
PSP = SD 
Incubation 
Nestlings 
Totals 
Eggs 
Nestlings 
Totals 
63 
53 
80 
267 
121 
388 
939 
735 
1.444 
2.720 
1,189 
3.909 
20.09 ± 0.43 
23.43 ± 0.68 
43.29 ± 1.08 
20.09 :± 0.43 
23.43 ± 0.68 
43.29 ± 1.08 
29 
23 
52 
95 
79 
174 
0.97 ± 0.01 
0.97 ± 0.01 
0.98 
0.96 ± 0.01 
0.93 ± 0.01 
0.95 ± 0.02 
0.53 ± 0.32 
0.49 ±0.17 
0.26 ± 0.21 
0.49 ±0.15 
0.20 ±0.12 
0.13 ± 0.07 
the interval between visits is small (Jehle et al. 
2004. Nur et al. 2004). We estimated confidence 
intervals for survival probabilities tollowing 
Hensler and Nichols (1981) and Mason (1985) 
lo compare nest success between egg and nestling 
periods: these values were compared to a normal 
distribution. We calculated the absolute (naive) 
survival of monitored nests as the percentage ol 
successful nests through each nest period (1 minus 
the proportion of lost nests during each nest 
period X 100). 
RESULTS 
Nests.— We found 103 nests and monitored 73; 
13 were inactive nests from previous breeding 
seasons and 17 were active, but >7 m in height, 
making them too high to be monitored. We were 
unable to ascertain the final fate of 10 ol the 73 
nests monitored, and these were excluded from 
the analyses. Seventeen nests were reused within 
the same breeding cycle, resulting in 80 active 
nests monitored when reuse was considered, and 
63 unique nests (Table 1). Nests were similar in 
structure and material composition. All were 
closed, hanging nests with a short (4-7 cm. n = 
2> tunnel entrance, constructed predominately 
trom dark fibrous fungi of the genus Marasmius 
'Fig. 1). Nests were suspended from thin tree 
branches usually hanging over streams (n — 59. 
94%); nests were also found hanging over diit 
roads (n = 4). in the forest interior (n = 1) or on a 
ravine of the main river in the study area (n — 1 )• 
Mean ± SE nest height was 3.1 — 0.1 m (n = 67). 
External nest dimensions were: 18.4 — 2.6 cm (n — 
9) in height and 9.8 ± 0.5 cm in = 9) in width. Nest 
entrances were 5.3 ± 0.2 cm wide (n = 4), and egg 
balls were 9.5 and 12.5 cm (n = 2) deep. 
Breeding Phenology.— The reproductive season 
of the Yellow-olive Flatbill began with the start of 
the rainy season. We found active nests from mid 
September through late December with a peak 
between mid October and late November coin¬ 
ciding with the first rains, and another peak before 
the start of the heavy rains in late December. Nest 
activity also coincided with a subtle increase in 
photoperiod (Fig. 2). First clutches were laid just 
FIG. 1. Nest of the Yellow-olive Flatbill hanging from 
a tree branch over the main stream on the Barreiro Reserve. 
Photograph by Paulo Cordeiro. 23 December 1996. 
