WORTHINGTON -- It really amazes me just how many comments I get regarding the general interest outdoor column I write on a weekly basis. I love those reader comments and I encourage you to drop me a note at rall@knology.net if you have any questions about a covered topic, or if there is a specific topic you would like to see in a future column. I even had a call from a guy in Texas a few weeks ago who had read my column on the NRA.
I received a note from a reader inquiring about the big vultures seen far more commonly soaring over southwest Minnesota. This is my attempt to answer some of those basic questions regarding the biggest bird regularly seen in our area.
They are the Turkey Vulture -- also known by the scientific name of Cathartes Aura. These birds are common all over North America during the summer months. They tend south in fall but are still seen from Kansas and other states that share those common latitudes and southward. There are actually five different sub-species of the bird.
They are scavengers and only eat things that are already dead. They prefer fresh kills and avoid those that have reached the point of no longer tasty. Road kill makes up the highest part of their diet -- there is nothing to big or too small. A dead cow or a dead rabbit both fit the menu just fine.
They fly at medium altitudes and can smell the gasses of decaying animals from great distances. When located, they then come in for a closer look. If the coast is clear then the dinner bell can ring. They have the ability to tear apart carcasses. Other scavengers like crows cannot accomplish this and need to follow after the bigger birds have made them an opening.
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Turkey vultures are really big birds. They grow up to 32 inches in length and have wing spans of right at 6 feet. Even with their big overall size they only weigh just under 4 pounds. These are daytime birds because they need thermals (rising heated air masses) to fly. They can soar for hours and literally never flap their wings.
By the time the sun goes down, these birds need to be roosted up for the night as flight is difficult without the sun. Even under good conditions these creatures have to work really hard to achieve flight. They run and hop about in an effort to gain enough speed to take off.
A great horned owl could, and would, kill a turkey vulture but by the time the owl comes out, the vultures are all tucked in for the night. For this reason they have few natural predators to control their numbers. Eagles manage to eat a few, but it is the raccoons and other predators that can raid the nest and eat the eggs or kill the young.
An adult turkey vulture can actually throw up undigested food at the threatening predator and, if they are successful, it causes a stinging sensation and the predator normally flees. If they are attacked by a predator they must eject any undigested meals they have consumed in order for them to take flight.
Turkey vultures prefer to roost in abandoned barns and other structures that have an access window. This is also where they can lay the customary two eggs and raise their young. The young are fed by regurgitation. This sounds quite unappealing unless you are a baby turkey vulture. They don't make a nest, and lay their eggs on just about any flat surface that allows them cover. They also lay eggs in hollow trees or other brushy spots. They have a long life span that averages 10 years in the wild, although they can live up to 30 years in captivity.
The city of Worthington built a new water tower at Centennial Park a few years ago and these less-than-beautiful birds have taken a liking to it. I have seen as many as 10 or more roosting on the top of it in the late afternoons. It is not uncommon to have large groups gathered and roosting together.
It seems to me there are many more of these birds around here than in past years. I called Bill Penning, Farmland Wildlife Director for the Minnesota Department of Natural Resources, to see if he could explain why this might be. In the end, neither of us could really come up with a definite answer.
I know there is a place in nature for every animal. Turkey vultures are nature's modern day Schaap Sanitation and do the work no other animal really wants to do. So, with this as their task in life, I will continue to watch them as they soar effortlessly looking for the next fresh meal. They, like many other birds, will be leaving Minnesota very soon for warmer climates.
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I am sure that next spring, like the tens of thousands of springs before that, we again will see them soaring high in the sky and mistakenly identify them as eagles.
Scott Rall is the Daily Globe's outdoors columnist. His column can also be read weekly at www.dglobe.com .
