Remarkable raptors rehabilitated at Vermont Institute of Natural Science

By RICHARD FROST
A Day Away

May 18, 2008 06:31 am

— For today's quick quiz, let me ask you, "What is a raptor?" Those who answered "a singer of hip-hop," well, you're wrong. Same for those who responded a person knocking at a door or window.
Okay, I think I heard a few of you in the back getting it right. A raptor is a bird whose diet depends on live prey.
If you didn't answer correctly -- or even if you did -- consider a trip to the Vermont Institute of Natural Science (VINS) for a chance to learn much more about these remarkable birds.
The Vermont Institute of Natural Science has its main campus just outside the tiny village of Quechee. Occupying a former quarry and farm site, the land includes third-growth forest, old stone walls and banks along the Ottauquechee River.
RAPTOR RESCUE
The institute claims a mission of protecting the natural heritage of Vermont. Education and research are two arms, while raptor rehabilitation marks the third. On-site and outreach programs bring ecological principles to adults and children across Vermont. But it's the raptors that make the center most unique.
The center rescues several hundred birds a year, of which at least half are able to return to the wild. Some of the others become permanent residents.
As we strolled along the raptor enclosures, we learned about the characteristics that make these birds good hunters. For one thing, they have excellent vision.
Owls enjoy night vision that's 100 times stronger than that of humans. Extra neck vertebrae allow them to swivel their heads 270 degrees in their search for prey.
Light skeletons facilitate staying aloft for long periods. Most kill with their powerful talons. Falcons also utilize strong beaks for that purpose. Swiftness helps, too. A peregrine falcon can fly 70 miles per hour then dive at three times that speed.
NARRATED HIKE
Keeping all this in mind made us glad these 30-plus birds lived behind wire. We looked at a new arrival, a snowy owl, then gazed upon the ominous red faces of the turkey vultures. But technically, vultures aren't raptors; they lack sharp talons and cannot kill their prey.
Barred owls are notable for the vertical lines on their breasts, while many know red-tailed hawks for their intimidating screams. Two ravens on display were larger than I'd anticipated. They're not raptors, either, but rank "among the most intelligent" in the bird kingdom.
There's more to do at the institute than just look at raptors.
Trails course through the 47-acre site. We decided to follow a staff member along a narrated half-mile loop. Erin, holding degrees in ecology and environmental education, proved quite knowledgeable about the terrain. Plus, she has a gift with children, easily involving them in the experience.
We passed a vernal pool, a seasonal wetland dependent on snowmelt and rain for its existence. Salamanders and frogs find such nutrient-rich spots ideal for breeding. Erin took a moment to tell us how amphibians turn out to be an important marker of environmental health.
In turning to the human relationship with the forest, she pointed out important tree species. Sugar maples are an important mature species here, as is the American beech. Beechnuts, high in fat and nutrition, are prized by squirrels, chipmunks and especially bears.
It's the white pine, however, that grows tallest. Many have split trunks, a result of invasion by the white pine weevil, whose larvae attack the leading shoot.
Some trees are "stump sprouters," like the cluster of five American basswood trees Erin pointed out. They spring from roots that survive fire, disease or lumbering. Red maple behaves similarly.
Besides harvesting timber, mankind impacts the land via agriculture. As we approached stone walls, Erin talked about the Merino sheep that once grazed here. The stones now provide home and shelter to a range of species, including spiders, mice, chipmunks, weasels and snakes.
Erin then brought us to old dams and to gnawed tree trunks. She reminded us beavers are second only to humans in their ability to alter the land surrounding them.
After our walk, we returned to the exhibit buildings. A special display on frogs captured our attention. Those throaty sounds frogs make at night are designed to mark their territory. The thin skin of frogs and other amphibians concentrates toxins, making them quite susceptible to chemicals added to their habitat. Thus, they become useful markers of pollution.
Some species utilize such capabilities for protection. Poison dart frogs in South America's rainforest apparently absorb noxious components of the insects in their diet, making their skin protective against those higher in the food chain. Natives have long taken advantage of this natural poison in making heads for projectiles, i.e. poison darts.
The frogs themselves are hauntingly beautiful, with their vivid red, yellow and blue colors. More importantly, the "pharmacy in their skin" offers potential chemicals useful for human medicine. As more rainforest gets destroyed, such opportunities dwindle.
Outside one building are stretched a series of ropes representing wingspans of commonly known birds. A hummingbird's span is only a few inches. At the other extreme stands the bald eagle, whose outstretched limbs can reach almost eight feet.
But back to the main attractions, the raptors. No one should visit the institute without taking part in one of the special shows demonstrating attributes of these remarkable birds. Staff member Craig, assisted by Hannah, taught and entertained us for more than an hour with their presentation on "What Makes a Bird a Raptor?"
A red-tailed hawk provided the opportunity to note the hooked beak, talons attached to strong feet and the forward-facing eyes with three-dimensional vision. Some hawks have the ability to glide up to 1,000 miles a day, needing to flap wings only once every 10 miles. The Cooper hawk, Craig told us, has become especially comfortable around people, to the point of swooping in and capturing birds on home feeders.
The next "special guest" was an American kestrel, part of the falcon family. His forte is focus, with the ability to keep his head still even while the body and wings move. Sort of like the image stabilization that my camera promises, I guess.
Then came a barred owl. Owls have superlative vision and hearing, plus the ability for silent flight. They, like most birds, lack an olfactory sense. Consequently, a great horned owl has no qualms about hunting skunks!
The turkey vulture, next on our live agenda, is the exception on smell. This carrion seeker can sense rotting prey seven miles away! The black vulture may have the better deal -- it lacks that terrific sense of smell but simply follows the turkey vulture to dinner.
I think I heard the hooting of an owl just as I finished this article. Wonder what's on his/her menu tonight.
rbforiole@aol.com

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