In response to the Turkey Vultures and Warbler post.
I'm sure you'll hear from others too, but for those of us who fly hang gliders
and paragliders, turkey vultures are one of our primary 'signs of spring'. These
birds live on the wing, migrating south in the fall as the sun drops lower in
the sky. That's because they're completely reliant on thermal updrafts for
their flight. Flight using sun-created thermals is how we stay up too, though
the TVs are far more efficient soarers than we are.
Turkey vultures and related soaring birds would starve to death if they had
to flap to stay aloft all the time searching for food. They count on the free
lift provided by the sun, and their own exquisite skill in locating that lift,
to be able to search large areas for carrion. Their incredible sense of smell
allows them to find their food because the sun-warmed air near the surface
rises, providing both lift and information on what's on the ground below.
Even human soaring pilots, handicapped though we may be with our inadequate
noses, can exploit this phenomenon. Soaring my hang glider over the orange
groves of central Florida, I could easily smell a thermal by the scent of
orange blossoms rising from the surface, or the unmistakable odor of cow
manure from the pasture next door.
When "the locals" return in spring, it means that soaring season is not
far behind. Their performance is better than what we can achieve with our
artificial wings, but if they're staying up, it's not long until the lift
builds to an intensity that will let us fly too. I've flown many times
with vultures and eagles, and if I've found a thermal first, it's not
unusual to be joined in it by the local birds, all of us turning together
in a rising aerial waltz.
Mark G. Forbes
Corvallis, Oregon
No comments:
Post a Comment