Photo by Nick Chill

© Nick Chill

On bright sunny days I can look up in the sky and see dark specks floating around high above. These specks are most likely Turkey Vultures. You see, I live in an area where Wild Turkeys graze the hillsides and sometimes our front yards. And, where there are Wild Turkeys, there are Turkey Vultures!

Seeing those dark specks floating high above in the clear blue sky made me wonder how high Turkey Vultures and other bird species fly, so I did some research to find if there was any data.

Stanford University essay states that vultures sometimes rise over 10,000 feet in order to scan larger areas for food (and to watch the behavior of distant vultures for clues to the location of a feast).

The essay also says, “Most birds fly below 500 feet except during migration. There is no reason to expend the energy to go higher — and there may be dangers, such as exposure to higher winds or to the sharp vision of hawks. When migrating, however, birds often do climb to relatively great heights, possibly to avoid dehydration in the warmer air near the ground. Migrating birds in the Caribbean are mostly observed around 10,000 feet, although some are found half and some twice that high. Generally long-distance migrants seem to start out at about 5,000 feet and then progressively climb to around 20,000 feet. Just like jet aircraft, the optimum cruise altitude of migrants increases as their “fuel” is used up and their weight declines. … Perhaps the most impressive altitude record is that of a flock of Whooper Swans which was seen on radar arriving over Northern Ireland on migration and was visually identified by an airline pilot at 29,000 feet. Birds can fly at altitudes that would be impossible for bats, since bird lungs can extract a larger fraction of oxygen from the air than can mammal lungs.”

© Ned Harris, Winkelman, Arizona, May 2010

Turkey Vultures fly with their wings in a dihedral or shallow V-shape, and can often be identified by this dihedral as well as by their characteristic “wobbly” rocking motion in flight. They are very graceful in flight and can soar for hours without flapping their wings. Their flapping, when it occurs, appears laborious and is usually used on take-offs and before landings.

Vultures begin flying a few hours after sunrise, after the morning air has warmed. Turkey Vultures frequently circle and gain altitude on pockets of rising warm air, or thermals. When they reach the top of the thermal, they glide across the sky at speeds up to 60 miles per hour, gradually losing altitude all the while. When they need to gain more altitude, they locate another thermal and so begins another sequence of circling, rising, and then gliding. Turkey vultures can cover many miles going from thermal to thermal without ever needing to flap their wings.

Contrary to popular belief, circling vultures do not necessarily indicate the presence of a dead animal.  Circling vultures may be gaining altitude for long flights, searching for food, or playing.

These unsteady soarers with very few wingbeats glide relatively low to the ground, sniffing for carrion, or else ride thermals of warm air rising up to higher vantage points. They may soar in small groups and roost in larger numbers. These birds ride thermals in the sky and use their keen sense of smell to find fresh carcasses. They are scavengers, cleaning up the countryside. You may see them on the ground in small groups, huddled around roadkill or dumpsters.

Resources

http://www.flickr.com/photos/nchill4x4/5129022466

http://www.stanford.edu/group/stanfordbirds/text/essays/How_Fast.html

http://www.allaboutbirds.org/guide/Turkey_Vulture/id/ac

http://vulturesociety.homestead.com/TVFacts.html

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