Avalos • REPRODUCTION OF SWALLOW-TAILED COTINGA 
253 
TABLE 1. Duration of parental 
(Phibaturaf. boliviano) at five nests. 
care of eggs (min/bout) by male and 
Values = mean ± SD. 
female Bolivian 
Swallow-tailed Cotingas 
Nest number 
Categories 
l 
2 
3 
4 
5 
Total hours 
24.5 
19.3 
19.3 
35.5 
19.6 
observed 
Incubation time 
Male 
49.8 ± 54.4 
57.1 ± 34.0 
119.3 ± 56.1 
98.4 ± 74.9 
80.3 ± 39.5 
Female 
35.7 ± 28.8 
48.5 ± 22.3 
39.3 ± 27.9 
72.5 ± 52.7 
51.7 ± 27.0 
Perching time 
Male 
7.5 ± 7.7 
36.5 ± 30.4 
10.0 ± 7.1 
20.0 ± 9.8 
Female 
3.5 ± 2.1 
14.0 ± 5.6 
1.8 ± 0.8 
5.0 ± 4.2 
Unattended eggs 
10.8 ± 7.2 
14.0 ± 7.9 
28.0 ± 18.3 
10.0 ± 5.2 
of failed nests. I followed Manolis et al. (2000) to 
calculate exposure days and Johnson (1979) for 
calculating standard deviations. Differences in 
survival rates between the incubation and nestling 
periods were compared using Program CON¬ 
TRAST (Hines and Sauer 1989). which uses 
covariance matrices, and the Chi-square distribu¬ 
tion. All values are reported as mean ± SD. 
RESULTS 
Nesting.— The first nest was found on 8 
November 2005 and contained one —13 day-old 
nestling. The last nest was discovered on 4 March 
2006 and contained one ~10 day-old nestling. 
Both parents constructed nests using lichens and 
thin twigs collected from trees with few leaves 
,c -g.. Alchomea triplinervia). Both parents emit¬ 
ted smooth guttural whistles with descending 
notes during the nest-building process. Nests for 
which construction was ''-20% complete required 
-3 - 0.8 days (range = 4-6, n = 5) to build. The 
clutch size of Phihalura f boliviano was two 
ff® 5 ' laid on 2 consecutive days (// - 7). The 
incubation period was 18 ± 0.8 days (range = 
17-19 days, n = 6) and the nestling period was 
27 - 1-7 days (range = 25-30 days, n = 9). The 
earliest age that a nestling left the nest was on day 
--T after being disturbed by cattle. 
Parental Care.— Both parents incubated the 
c Sgi (92% of the time) with interchange every 
tour on average (Table 1). However, parents also 
s tont time defending their territory from other 
roated pairs in the early stages of incubation, and 
torching in trees near the nest site (Table 1). The 
^can duration of incubation for males was 
s, gnificantly longer than for females (males: 
30.1 ± 12.4 min/hr; females: 20.7 ± 10.3 min/hr; 
paired t -test = 2.2. df = 22, P = 0.037). Time spent 
perching in trees did not differ significantly 
between males and females (paired r-test = 1.0, 
df = 13. P = 0.328). 
Parents allocated their time during the nestling 
period to different care-related activities (Fig. 1, 
Table 2). Parents initially provided almost con¬ 
tinuous care for small nestlings (99% of time), 
brooding with a rate of interchange of 12 to 27 min 
(Table 2) and showing an alert position when it 
was time to feed them. However, total attendance 
by parents at a nest (parental care at both the nest 
and from a distant tree perch) declined as age of 
nestlings increased (Fig. 1). Mean brooding time 
decreased with nestling age (F = 14.5, df = 4, 
Nestling age (days) 
FIG. I. Proportion of time in different parental care 
behaviors of Bolivian Swallow-tailed Cotinga (Phibaturaf 
boliviano ) nestlings by age group. TA = Total attention. 
BR = Brooding. PN = Perching near nest. PT = Perching 
in trees of nesting area. 
