Only the largest birds have a wingspread and silhouette sufficient to cast an eye-catching shadow as they pass overhead, interposed between us and the sun. Soaring birds, especially, ride updrafts on virtually motionless wings, their stillness making the shadow they cast even more apparent.

Two familiar soaring birds are a common sight in my neighborhood. But their fleeting shadow is usually not a foolproof identifier, and usually requires a turn of the head—eyes focused skyward—to confirm their identity. As I mowed and did yard work over the long Labor Day weekend, both were in evidence overhead.

The point where land and water meet seems a particularly good place for these birds to catch updrafts that keep them aloft with a minimum of wingbeat effort. The first to put in an appearance was following the shoreline, not much above treetop level, though “treetop” can be white pines standing 50 feet tall, or more. It took mere seconds scanning the sky to pick up the fan of brilliant white tail feathers, then the white-feathered head, that confirmed the bird’s identity as a bald eagle. They’re a relatively common sight here, so the sighting was no surprise.

Though we glorify it on our coins, our federal buildings, government documents and what-have-you, the bald eagle is as much a scavenger as it is a symbol of power. One of the reasons bald eagles are found near water is the prospect of an easy fish meal. This can be the result of caught-and-released fish that do not survive; perhaps a result of hooking injury, or being brought up quickly from great depth. Fish also die in some lakes due to summertime oxygen depletion, and scavengers in the vicinity—including eagles--benefit.

Some bald eagles are drawn to popular duck hunting waters. There they occasionally pick up birds that have been wounded or killed by a duck hunter, but unfortunately not retrieved. It’s happened to me. A duck has been harvested and is drifting motionless at the edge of the decoys. As I’m preparing to row out and retrieve it, a bald eagle cruising over the lake has spotted the floating duck, homes in on it and—to my open-mouthed surprise—glides down and snatches it. Adaptive scavenging, for sure.

The second of these soaring birds casts a shadow not markedly different from the first. But when eyes turn skyward, the differences become evident. This bird has narrower wings, the feathers at the tips more widely spread—almost like fingers. A shorter neck joins this bird’s head with the “fuselage” between its wings. It’s entirely dark, and lacks any visibly bright plumage; head, tail or anywhere else.

In its dining habits, this bird is not so different from the bald eagle, scavenging meals where it can find them, though it is chiefly an over-the-land hunter. This second soaring bird is the turkey vulture. Unlike the bald eagle, few humans hold the vulture in high esteem. We even use “vulture” as an epithet to describe someone who takes advantage of the misfortune of others.

This scorn, despite the bird’s service to Nature in recycling wild or domestic creatures that have died of natural causes, or at the claws and fangs of predators. This prejudice is not uniquely American. Though you’ll find eagles on flags, coats-of-arms and in other symbolisms in many countries, you’ll look far and wide to find any similar recognition given to the vulture.

We tend to make similar judgments of worth or desirability with other creatures, too. We value the brown or brook trout we take from a river or stream, but thumb our nose at the chub or sucker taken from the same water. We prize the walleye, but scorn the eelpout (except during the winter Eelpout Festival in Walker, Minnesota!). We harvest ducks with enthusiasm, but are embarrassed if we shoot a coot, even though a creative cook can make one into a delicacy.

We find the red-winged blackbird cheery and handsome, but see the jet-black, yellow-eyed grackle as a stealthy and murderous nest robber. We find frogs interesting and appealing, but toads creepy, never to be touched. Centipedes creepy, but caterpillars cute. And so on, with fish, fur or fowl.

There’s little rhyme or reason to some of these prejudices, other than to concede that we’re a bundle of biases and contradictions; including where Nature is concerned!