For almost all of human time (we assume) we have been bird watching and envying their ability to defy the laws of gravity and move at will through the air. The ancient Greek myth of Daedalus and Icarus is an excellent example of that yearning. Daedalus was able to create wings with branches and wax for him and his son Icarus, but once airborne the exhilaration caused Icarus to forget the warnings from his father not to fly too close to the sun. His high flying freedom soon melted into disaster and he fell into the sea. While that story has lots of lessons tied into it, it did nothing to stop humans from actually trying to replicate those mythical wings and flight. In fact it may have inspired others to try.
Through the centuries various designs appeared, including detailed ones by Leonardo da Vinci. It wasn’t until the early 20th century that we managed to make true extended flights, and then we soared even higher than ever imagined, ultimately reaching the moon. We could say that all of these accomplishments stemmed from observations of the creatures with feathers.
I have known this desire to fly, both in my dreams and in actual fact. Back in the 1970s I attempted to learn how to hang glide. It was a short lived attempt, since the hills available in the Minneapolis area didn’t give you much time or distance to get airborne. The equipment was heavy and rudimentary and ultimately I decided it probably wasn’t the best sport to take up as the mom of two young children. Thirty years later, my son Jon, who lives in Bozeman, MT, has taken up paragliding. He too has always wanted to fly, but couldn’t afford airplane lessons. In theory I understand his desire to glide above the earth, but in reality it makes me very anxious to know he is going to be soaring hundreds of feet in the air after launching
from nearby mountains. This is one of those very difficult conundrums we sometimes face as parents, even if your child is in his 40s.
Meantime, the birds continue to take flight in stride and show no signs of wishing to escape the boundaries of our atmosphere. Archaeopteryx is the oldest known fossil of an animal that had wings and feathers. Discovered in 1861 in a German quarry, the fossil was dated to 150 million years ago. This small dinosaur (20 inches from head to tail) had teeth, claws on the ends of its wings, and a long reptilian type tail with feathers on either side. Yet, the structure and arrangement of its feathers were similar enough to birds today, that scientists believe it could fly.
How that original flight came to be is up for grabs. It is believed that the feathers evolved for reasons other than flight; the need for thermal regulation and an aide in catching prey. Some believe it was a ground dwelling species, running and flapping its wings, which eventually led to gliding over the ground, while others believe it was a tree-dwelling species and hopped from branch to branch, using the wings passively to glide down. Eventually, through countless iterations, and some inevitable dead ends, the flapping became forceful enough to allow flight and eventually soaring.
Over the ages, wings have evolved to match the bird and its particular size and needs, based on its habitat and diet. Whether the birds are searching for insects or wild bird seed, wings can be long and narrow, others broad and short, with every configuration in between. Generally speaking the longer and more pointed the wing, the greater the ability to maneuver and travel fast. Good examples are the swallows and falcons. The larger the surface of the wing, the greater the ability to soar; examples include pelicans, eagles and turkey vultures. While I have just pointed out that birds do not venture into space, bar-headed geese come close, flying over the Himalayas at an altitude of almost 24,000 feet.
Birds need to be able to fly at least 11mph to remain in the air. House sparrows have one of the slowest
speeds – around 16-19 mph, while spine-tailed swifts have been clocked at 218 mph in a straight-forward flight. The majority of birds fall in between these two extremes. These have been measured by radar similar to those used by police sitting on the side of the road in wait for a speeder.
As I write, my attention is constantly averted by the blur of wings at the window. The hummingbird feeder is both an entertainment and a distraction. One can’t help but be mesmerized by wings that beat 55 times per second when hovering, 75 per second when flying straight forward and 61 times per second when backing up. It is no wonder that a hummingbird’s chest muscles account for 20 percent of its mass. According to Bret Tobalski, a University of Montana physiologist, “If a human had that mass of muscles, it would stick out like a 55 gallon drum.”, concluding, “It would be freaking enormous.”
By Kate Crowley