Scavengers of the breeze
Growing up in the small southeastern Minnesota community of Harmony put me in close proximity to the Iowa River. Periodically on hot sultry summer days, I would cool off by wading the cool waters of that river in quest of small-mouth bass.
In addition to catching a few fish, the highlights of those adventures were avoiding timber rattlesnakes that would come down off the adjacent bluffs in search of water and sighting a very rare turkey vulture.
It was thrilling to observe these large black birds that at the time we referred to as "buzzards" soaring high on uplifting thermals over the river.
During the long span of years since those fond memories were made, the biodiversity of our planet and the local environment has been greatly diminished for a number of reasons. As some species struggle to survive, others are much more adaptable to changing habitat conditions and seem to be thriving. Common and well-known wildlife doing quite well these days include whitetail deer, coyotes, grackles, Canada geese, crows and turkey vultures.
Given the fact that we are currently experiencing a large increase in our resident bald eagle population, it is sometimes easy to confuse an eagle with a turkey culture. One easy way to differentiate between the two is that vultures soar with their wings in a "V" or dihedral position. Eagles tend to hold their wings horizontal. In addition, vultures tend to soar in groups of several birds and appear headless.
The red-skinned head of the turkey vulture has no feathers thus enabling it to feed deep inside a rotting carcass without caking its feathers with smelly blood and guts. It is not all that uncommon to observe vultures feeding on road killed deer or raccoons.
The vultures have a habit of gorging themselves to the point of having great difficulty in getting airborne. Unfortunately, this creates a bad situation for vultures feeding alongside a busy highway.
On the 1987 Environmental Learning Center Instructor Naturalist kayaking expedition on the Rio Grande in south Texas, we were receiving a shuttle ride from Dryden back to our point of departure in Big Bend National Park. In the course of that ride, I commented to the driver that there seemed to be an unusually high number of vultures along the highway.
He quickly responded with his acute dislike for these birds. It seemed as though within the past few years, he had replaced a couple windshields as a result of vulture collisions.
We also learned from him that the natural reaction of a vulture when faced with impending danger is to regurgitate its last meal. He concluded this discussion by telling us he had patronized his local car wash on several occasions.
The turkey vulture has a highly developed sense of smell and a very unique digestive system with a resistance to botulism thousands of times higher than humans. Their digestive tract contains chemicals that kill the virulent bacteria found on the decaying food they eat.
On early morning summer kayak outings in the backwaters at the head of Lake Pepin, I have observed communal roosting sites usually located in a large dead tree along the shoreline. In the early morning sun, several birds will have their wings outstretched to dry the dew giving the appearance of honoring the rising sun. The morning sunlight also serves as a disinfectant for their head and feathers.
Most recently on May 17, I climbed Barn Bluff early in the morning and was fortunate enough to surprise a dozen vultures standing on the ground at the far east end.
Upon closer examination with my binoculars, I observed that one of the birds wore a light blue wing tag with the black number of 45.
Three days and six phone calls later, I learned that researchers from Hawk Mountain Sanctuary in Pennsylvania had banded 170 turkey vultures in December 2006 in northwest Venezuela.
According to Dr. Keith Bildstein from Hawk Mountain, the main purpose of the tagging project was to learn where the vultures returned to for the nesting season. Researchers were also interested in determining the timing of the spring migration.
It is estimated that every fall 2 million and possibly 3 million turkey vultures funnel through the countryside near Vera Cruz, Mexico, on their migration to South American wintering grounds.
Circling kettles of up to 5,000 birds are sometimes observed at this time.
In the spring, the migration consists of much smaller groups, commonly a dozen in number.
My report of wing-tagged vulture No. 45 was the first observation to date. As you are out enjoying the great Red Wing outdoors this summer season, keep your eyes open for additional tagged birds.
Future sightings can be reported to: Hawk Mountain Sanctuary,(570) 943-3411; or e-mail Bildstein@hawkmnt.org