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THE WILSON JOURNAL OF ORNITHOLOGY . Vol. 123. No. 3. September 2011 
TABLE 1. 
Call characteristics (mean ± 
SD) of Alipiopsitta xanthops repertoire in Brasilia, Brazil. 
Call (a) 
Max F (kHz) 
Min F (kHz) 
Bandwidth (kHz) 
Duration (ms) 
# Pulses Pulse rate (Hz) 
Flight call (15) 
1.82 ± 0.53 
0.56 ± 0.20 
1.25 ± 0.54 
237 ± 22 
LR-alarm (49) 
1.46 ± 0.37 
0.59 ±0.11 
0.87 ± 0.41 
239 ± 16 
Agonistic I (16) 
3.85 ± 0.30 
1.03 ± 0.08 
2.81 ± 0.32 
154 ± 8 
Agonistic II (6) 
1.23 ±0.18 
0.73 ± 0.20 
0.49 ± 0.20 
141 22 
6.75 + 1.2 50 + 5 
Sentinel (29) 
1.26 ±0.11 
0.74 ± 0.07 
521 ± 110 
124 ± 10 
2.0 + 0.56 
SR alarm (5) 
1.46 ± 0.13 
0.86 ± 0.11 
599 ± 159 
179 ± 13 
Sentinel Call. —This vocalization was heard 
only during feeding (Fig. IE). It was common to 
observe one or two individual sentinels, perched 
on lop branches, emitting these sounds while 
observing the surroundings. The rate of emission 
was quite variable. Calling rales reached two 
calls/min using a 5-min recording. It has funda¬ 
mental frequencies between 0.7 and 1.2 kHz and 
duration of 120 ms (Table 1). This vocalization 
appears to inform the presence of a sentinel to 
other Hock members, as visual contact may not be 
possible in dense trees. Other calls were also 
heard during feeding, but it was not possible to 
describe the response, as there were too many, and 
we had great difficulties recording them within 
the feeding context. 
Short-range Alarm Call.— This vocalization 
was rarely heard, and is quite different from the 
long-range alarm call (Fig. IF). However, the 
response to this message was clear. As a response 
to this call, signaled by a flying individual, a 
perched parrot would fly silently, due to a danger 
situation. It has short range and does not give 
away the parrot's position, allowing furtive flight. 
Trees rapidly block the view of flying parrots and 
make it difficult to locate them. The fundamental 
frequency is between 0.8 and 1.5 kHz and 
duration '180 ms (Table 1). At times, it was 
uttered with a preliminary note. However, the low 
quantity and quality of the recordings did not 
allow us to fully understand the preliminary note 
function, nor if it could alter the response of the 
recipient parrot. We recorded it on five occasions, 
usually with low quality. However, we made other 
observations of the same reaction following this 
call. 
Amplitude Comparisons. —Call intensity com¬ 
parisons revealed a great amount of variation 
between calls. Long-range alarm calls were 
14.7 dB louder than sentinel calls ((/-test P < 
0.001). Agonistic vocalization 1 was 11 dB louder 
than agonistic vocalization II ((/-test P < 0.001). 
Congregation long-range calls can be 10 dB 
louder than long-range alarm calls; however, as 
relative intensity estimates of long-range alarm 
calls were made using medium size feeding 
flocks, differences of intensity could be greater 
for roosting flocks. 
DISCUSSION 
The Yellow-faced Parrot repertoire has a clear 
division between short- and long-range calls. 
Fernandez-Juricic (1998a) used the term 'guttural 
vocalizations’ for short-range vocalizations in the 
Turquoise-fronted Amazon. We prefer to use 
long-range or short-range vocalizations, as gut¬ 
tural refers to the timbre and not range, and range 
has a major role in parrot communication. We 
also observed other species with long-range/short- 
range communication, including Red-shouldered 
Macaw ( Diopsittaca nobilis ), Peach-fronted Par¬ 
akeet ( Aratinga aurea). Yellow-chevroned Para¬ 
keet ( Brotogeris chiriri ), Blue-and-Yellow Ma¬ 
caw' (Am ararauna ), and Turquoise-fronted 
Amazon. Proper repertoire descriptions are nec¬ 
essary to fully identify the scope of long-range 
communication in Psittacidae. These studies 
should include sound intensity and decay mea¬ 
sures, so we could fully comprehend the mecha¬ 
nism used to attain higher ranges, and its 
peculiarities among different species. 
Flocks were constantly dividing and regrouping 
during feeding (feeding flocks). At nighr a large 
flock was formed to roost (roosting flocks). Our 
data are consistent with those of Carrara el al. 
(2007) for the Yellow-faced Parrot, where max¬ 
imum flock sizes were only achieved during 
preparation for roosting. Parrots were observed 
foraging in flocks rarely larger than 20 individ¬ 
uals. while flocks of up to 160 individuals were 
observed during roosting congregation. Our data 
suggests feeding may have a central role in this 
pattern, as it indicates a direct relation between 
flock size and tree size. Other studies of different 
