Clark el al. • SCINTILLANT AND VOLCANO HUMMINGBIRD COURTSHIP 
219 
Male S- flammu'a torridus 
Male S. scintilla 
FIG. I. Male Scintillant (Selasphorus scintilla) and Volcano (S. flammula torridus) hummingbirds with rectrices 
labeled R1-R5. R1 and R2 are emarginatcd in males (arrows). Emargination is more pronounced in the Volcano 
Hummingbird. Photographs courtesy Anad Varma. 
83 48'26.01" W; 2,200 m asl), San Jose Province. 
All observations occurred between 12 and 22 
October 2009. 
We obtained high-speed videos of hovering and 
displaying hummingbirds with a hand-held mono¬ 
chrome high-speed camera (MIRO EX4, Vision 
Research. Wayne. NJ, USA) recording at 500 fps 
with a resolution of 800 X 600 pixels. We 
obtained sound recordings using a shotgun 
microphone (Sennheiscr MKH70, Wedemark- 
Wennebostel, Germany) attached to a 24-bil 
recorder (Sound Devices 702. Reedsburg, WI, 
USA), sampling al 48 kHz. Recordings were 
imported into Raven 1.3 (www.birds.corncll.edu/ 
raven) and converted into spectrograms using a 
512-sample window (Hann function. 50% over¬ 
lap), except where otherwise indicated. Acoustic 
frequencies and temporal rates presented repre¬ 
sent the frequencies recorded by the microphone 
and were not corrected for Doppler shift caused 
by the birds" velocity. 
We captured hummingbirds with either mist 
nets (24-mm mesh) or feeder-traps. Some record¬ 
ed sounds were natural, and the remainder were 
elicited by placing a live female in a cage on a 
male's territory, or by releasing a recently- 
captured female onto a homospecific male’s 
territory. Volcano females were released on a 
male Scintillant’s territory a few times, due to a 
scarcity of Scintillant females, but failed to elicit a 
response. We collected tail feathers for laboratory 
experiments, and we opportunistically obtained 
dive recordings from one male Volcano Hum¬ 
mingbird both before and after plucking his entire 
tail. More extensive manipulations of wild birds 
(as in Clark and Feo 2008. 2010; Fen and Clark 
2010) were unfeasible as these experiments 
typically take a few weeks. Tail feathers from 
each species were tested in a wind tunnel to 
ascertain if they were capable of producing 
sounds similar to the dive sound. This tunnel will 
be described in a future publication. All measures 
are mean ± SD. Specimens associated with this 
research have been deposited in the Peabody 
Museum. Yale University. Sound recordings have 
been deposited in the Museum of Vertebrate 
Zoology, University of California. Berkeley. USA 
(accession # 14752), and videos have been 
deposited in the Macaulay Library (accession #'s 
ML65124 to ML65144), Cornell University, 
Ithaca, New York, USA. 
RESULTS 
Volcano Hummingbird 
Breeding and Territorial Behavior—We saw 
females gathering nesting material and located 
two active nests with females incubating eggs at 
Cuerici on 15 October 2009. indicating breeding 
