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SCIENCE Wednesday 22 July 2020
Ecuadorian hummingbirds chirp ultrasonic songs of seduction

By CHRISTINA LARSON sing at high pitches so that
AP Science Writer their love songs wouldn't
WASHINGTON (AP) — compete with background
Perched on a flowering noises in their environment,
shrub on a windy Andean such as mountain winds,
mountainside, the tiny Ec- streams and the songs of
uadorian Hillstar humming- other birds, said Marco
bird chirps songs of seduc- Monteros, a study co-au-
tion that only another bird thor and biologist at Univer-
of its kind can hear. sidad Técnica del Norte in
As the male sings, he in- Ibarra, Ecuador. "For some
flates his throat, causing iri- hummingbirds, it's like a pri-
descent throat feathers to vate channel of communi-
glisten princely purple. The cation — other bird species
female may join in a court- don't use these high-fre-
ship dance – or chase him quency sounds," said Timo-
off. thy Wright, a behavioral
For the first time, scientists ecologist at New Mexico
have shown that these State University, who was
hummingbirds can sing not involved in the study.q
and hear in pitches be-
yond the known range of
other birds, according to
research published Friday This 2019 photo provided by researcher Fernanda G. Duque shows a male Hillstar hummingbird
in the journal Science Ad- singing a high frequency song perched on a Chuquiraga jussieui flower in Ecuador.
vances. Associated Press
The male's ballad is sung at
around 13.4 kilohertz. That's shown to hear ultrasonic singing, then played back study co-author at Georgia
considered "ultrasonic" for sounds — which they use their romantic ballads to State University, where she
birds, which generally can't to locate prey, but not to test the reactions of other researches hummingbird
hear above 9 or 10 kilo- communicate. Biologists birds. brains.
hertz. have studied other hum- Other Hillstars craned their Mammals generally hear a
"Something very interest- mingbird species in South necks and turned toward wider range of pitches than
ing is going on in the ears America that make high- the speaker as it played the birds. Humans can hear
of these hummingbirds to pitched sounds, but it's high-pitched chirps; one pitches up to about 20 kilo-
allow them to hear such been difficult to confirm also flew over the speaker hertz, but lose sensitivity to
sounds," said Christopher whether those birds also to inspect it. In the lab, the high-pitch sounds with age.
Clark, a biologist at the Uni- hear the sounds. scientists verified that the During fieldwork, the
versity of California, River- For the new study, scientists part of the brain typically younger scientists could
side, who was not involved climbed into the Ecuador- engaged in auditory com- usually hear the Hillstar
in the study. ian Andes to reach high munication had been acti- hummingbird songs, but
"That's just an incredibly grasslands called paramos vated. the older participants
high pitch for a bird." and locate the Hillstars' "We confirmed that this couldn't, Duque said.
Among birds, only some breeding grounds. There song has a social function," The researchers believe the
owls have previously been they recorded the males said Fernanda Duque, a birds may have evolved to

Astronauts squeeze in last spacewalk

before SpaceX departure

CAPE CANAVERAL, Fla. (AP) commercial airlock later
— Astronauts squeezed in this year.
one last spacewalk Tues- Behnken had to scrape
day before turning their at- away a shiny metallic
tention to the all-important blob — some sort of de-
end to SpaceX's first crew bris — from the round rim
flight. of the port. This port is the
Making their fourth and future home of a domed
final spacewalk in un- airlock provided by the
der a month, NASA's Bob Houston-based company
Behnken and Chris Cassidy Nanoracks to release satel-
whipped through a vari- lites and experiments into
ety of maintenance tasks open space.
outside the International SpaceX will launch this first-
Space Station. ever commercial airlock This photo provided by NASA shows astronauts Bob Behnken
Instead of swapping bat- this fall. and Chris Cassidy on a spacewalk outside of the International
teries, they routed cables, It was the 10th spacewalk Space Station on Tuesday, July 21, 2020.
hooked up a tool storage in each astronaut's career, Associated Press
chest and removed ther- tying the U.S. record set by
mal shielding from a dock- previous space station resi- outing put Behnken's total space at 61 hours and Cas-
ing port that will house a dents. Tuesday's 5 1/2-hour time out in the vacuum of sidy's at nearly 55 hours.q