Hmmmmmmmmmmmm, I am going to search for the real meaning now,lol!
https://www.geek.com/geek-cetera/ho...ound-during-elaborate-mating-rituals-1420103/
If this is really true!
How hummingbirds make such awesome sounds
By
Jennifer Bergen 09.10.2011 :: 9:02AM EDT
If you want to impress your friends over your weekend drinks or brunch, then listen up. A
Yale University zoologist has figured out what exactly makes a
hummingbird hum. The hummingbird is one of the smallest of all birds, with the smallest, the Bee Hummingbird, at just 5 cm. Though tiny, these birds can produce quite a hum, which is where their name is derived from.
Yale student Christopher Clark studied the characteristics of the hummingbird and reported his findings in a paper published in the Sept. 9 issue of
Science. Clark found that in addition to the mesmerizing mid-air hovering that hummingbirds are known for, the other trait they’re known for (the humming) comes from the males who make the sound with their tail feathers while courting lady hummingbirds. Clark found that the air flowing past the tail feathers makes the male’s feathers flutter and generate a humming sound.
Apparently, the birds only make the sound during their elaborate mating rituals that typically see a male flying up to 40 meters into the air and then dive-bombing down right past the casually-perched female. When the he-bird reaches the lowest part of his dive, he quickly spreads and then closes his tail feathers which expose them to air. This in turn causes the flutter sound. Also, like a tuning fork, when one feather vibrates, it causes the one next to it to vibrate, and so on, creating a loud sound. Clark found that two feathers fluttering together can make a sound about 12 decibels louder than two that are fluttering independently.
The birds can fly at speeds exceeding 15 m/s and, depending on the species, can flap their wings 12 to 90 times per second. So how is it that Clark was able to deduce that it’s the tail feathers that cause the sound if these little birds are moving so quickly? As you can see in the video below, Clark recreates some of the sounds by putting the feathers in a wind tunnel and turning the air speed up to a range similar to their dives. He took high-speed video of the wings’ flutters that were recorded at 23,000 frames per second and were slowed down by 1,000 times. He also analyzed the fluttering sounds by measuring the sound of hummingbird feathers with a Scanning Laser Doppler Vibrometer, which is an instrument used to measure a surface’s vibrations.
Not only did Clark discover the reasoning behind the humming sound; he also found out that each species has a “signature sound.” The researcher said in a
press release that the sounds the feathers can make are more varied than he expected. Each species has a different frequency, volume, and sound which come from factors like the size, shape, stiffness, and mass of the feathers.
Though he’s still not sure why males have evolved to create sound with their tail feathers during courtship, Clark hypothesizes that female hummingbirds might prefer the mate who’s the best flyer. The volume of a male’s tail feathers would mean he’s very fit, and males dive fast to increase the volume of their fluttering to create a louder hum.
Also, a fun little tidbit for you, hummingbirds are the only group of birds that are able to fly backwards.