Clark et al. • SCINTILLANT AND VOLCANO HUMMINGBIRD COURTSHIP 
223 
any behavioral observations of this species at 
Cuerici. and found no evidence of breeding at this 
location. 
Scintillant Hummingbirds were breeding at San 
Gerardo (2.200 m asl). We observed females 
gathering nesting material and a female incubat¬ 
ing a nest in a low bush on 13 October 2009. The 
nest did not appear to be on or near a male 
territory. 
Males held territories in open areas such as the 
edge of an apple (Maius spp.) orchard, in a dense 
stand of blooming Fuchisia paniculata. or in short 
trees flanking a parking lot. All territories were in 
open areas, and males perched in 3-5 prominent 
locations between 2 and 15 m above the ground, 
on objects such as power lines, tips of dead twigs 
protruding from a large tree, on the tops of banana 
(Musa spp.) leaves, or the upper-most branches of 
a heavily blooming Fuchsia. All male territories 
contained at least a few plants in flower, and one 
included a hummingbird feeder. 
The size of a territory varied depending on the 
amount of available food. Three males held 
densely-packed territories in a thick patch of 
blooming F. paniculata with all of the male’s 
perches in a roughly 10 x 10 m area. These 
territories were also immediately adjacent to 
feeding territories held by both male and female 
Volcano Hummingbirds. Four territories found 
elsewhere, in areas with fewer natural food 
resources and fewer neighboring territories, were 
roughly 25 X 25 m in extent. 
Natural dives were performed to female 
Scintillant Hummingbirds, or to hummingbirds 
of unknown gender. A female Scintillant repeat¬ 
edly visited flowers on a male's territory during a 
set of natural observations spanning ~5 min. The 
male performed two sets of three dives to the 
female, and spent the rest of the time watching her 
while occasionally producing a type a call, or 
chasing her. Male Scintillant and both male and 
female Volcano hummingbirds that entered the 
males' territories were scolded and chased. In 
general, the behavior of the territorial males 
seemed similar to that of male Rufous and Allen's 
hummingbirds, in terms of activity, vocalizations, 
and tendency to engage in aggressive interactions 
with other hummingbirds (CJC, pers. obs.). 
Vocalizations. —Males did not sing undirected 
song from their perches. They did produce at least 
three types of calls, two of which are labeled a 
and b (Fig. 4A). A third, apparently agonistic 
(scolding) call was produced, often while perched. 
and sounded similar to a call produced by Allen’s 
and Rufous hummingbirds. We did not obtain a 
clear recording of this call. Both males and 
females at times produced call a in the apparent 
absence of other hummingbirds, while the other 
two calls seemed to be produced only in agonistic 
interactions. 
Wing Sounds and Shuttle Display.— Male 
Scintillant Hummingbirds produced a distinctive 
wing trill during flight (acoustic frequency: 9 kHz; 
Fig. 4B) that sounded nearly identical to the wing 
trill of Allen’s and Rufous hummingbirds. Males 
also produced a shuttle display characterized by 
distinctive sounds and flight kinematics similar to 
the shuttle displays performed by Allen’s and 
Rufous hummingbirds. The shuttle displays had 
two variants, 'stationary' and 'traveling’. A male 
repeatedly approached a female in a cage and then 
produced a stationary shuttle, in which he flew 
back-and-forth while producing the sound. This 
variant was also heard emanating from inside of a 
bush into which a male had pursued an uniden¬ 
tified hummingbird. In the second variant, males 
(n = 2) that spotted a female crossing their 
territory would leave their perch and pursue the 
female, but not at their top speed. In this traveling 
shuttle, as they followed the female, the males 
would occasionally produce the shuttle display 
sound, visually appearing to decrease their 
forward flight speed and change their wing beat 
kinematics as they did so. 
We obtained five sound recordings from two 
males performing the shuttle display (Fig. 4D). 
Males produced similar sounds during the travel¬ 
ing and stationary variants of the shuttle display. 
The shuttle display sounds consisted of repeated 
sounds that appeared in alternating duplets. One 
pair of sounds matched the acoustic form of the 
male’s wing trill (i.e., sound pulses with a mean 
acoustic frequency of 9.4 ± 0.43 kHz and a 
frequency bandwith of 1.87 ± 0.28 kHz; n = 5; 
labeled w in Fig. 4D). The alternate duplet (s in 
Fig. 4D) was a broad-band sound without a single 
discrete frequency. The trill rate was 93.8 ± 
5.1 Hz (/? = 5). 
High-speed videos of four shuttle displays from 
one male were recorded. The male was partially 
obscured behind other objects or, at times, out of 
frame throughout most of the videos, and sample 
sizes of specific events vary. The male flapped his 
wings at 98.1 ± 2.64 Hz (n = 4 displays) during 
the shuttle display, while rhythmically moving his 
body. We term each repeated, rhythmic move- 
