Blane Klemek: Ospreys have adapted to their environment
I watched an American robin a few mornings ago on my lawn struggling with an oversized nightcrawler, yanking at the annelid as it tried to pull the hapless meal out of the ground. The robin eventually won the tug-of-war, and off it flew with its breakfast.
One of my thoughts as I observed the bird was how this familiar native avian neighbor of ours must have fared before Europeans populated this continent, cleared the forests, built cities and towns and began mowing lawns. The robin, as we all know, is a bird that is as at home in the Boundary Waters Canoe Area Wilderness as it is in most any American urban center. The species has adapted very well with and without our influence.
I had a similar thought last week while traveling U.S. Highway 10 northwest of Frazee, Minn. A few miles between the cities of Frazee and Detroit Lakes, a utility line crosses the highway. Adjacent to the roadway and supporting the overhead power line is a steel lattice structure support-tower. On top of the structure is a nesting platform with a large stick-nest sitting "naturally" on the platform. And inside the nest are two growing osprey chicks. I've delighted in watching the nestlings grow day by day.
Like the robin, the osprey appears to be a bird that has benefited from a manmade environment. The bird has adapted very well to our presence and routinely nests on structures such as utility poles. Indeed, ospreys are an interesting bird. Often called a "fish hawk or fish eagle," these latter names are aptly assigned for good reason - the osprey's principle prey is fish. It is no wonder that this elegant hawk makes its home throughout Minnesota's thousands of lakes, wetlands and rivers.
The osprey is fairly easy to distinguish. With a wingspan of over 5 feet and a body length from beak to tail at about 2 feet, the bird is sizable among hawks and eagles. In flight, ospreys are sometimes confused with gulls and eagles. But the manner in which ospreys fly and hold their wings will often be enough for proper identification.
A distinctive kink at the elbows gives the wings a kind of swept-back appearance in the shape of a subtle looking "M." And if you're lucky enough to observe an osprey do what they do best, catching fish, then you've seen what really sets them apart from other fishing birds.
I'll never forget the first time I witnessed an osprey hunting for prey. I was a young boy canoeing on the Crow Wing River and enjoying the thrills of new adventures around every bend. Floating lazily along a scenic stretch of the river that cuts through farmland on one side and jack pine on the other, I was alerted by a loud splash a few hundred feet downstream.
My canoe partner powering the bow was equally as surprised and so the two of us immediately ceased paddling. We watched as a large and obviously wet bird emerged from the river like some giant hatching mayfly. The bird flew straight up and began to hover effortlessly some 30 or so feet above the water.
A few seconds later it abruptly fell from the sky as though forgetting to flap its wings. In an instant the bird entered the water in a thunderous splash, feet first, disappeared momentarily in its own wake, and reemerged, beating its wings laboriously, but this time, clutched tightly in its talons, with a prize: a squirming fish.
I watched the fish hawk control and subdue its struggling prey while it continued on in flight. The osprey, clutching the fish with one foot in front of the other, positioned the fish head first, parallel to its own body. The image of the bird's underside while carrying the fish suspended below itself was not unlike that of a sailboat's keel.
Ospreys plumage coloration is classic among the animal kingdom. Colored white below and dark above, or as is often referred to as "disruptive coloration," many other species of fishes, amphibians, birds and mammals exhibit similarly contrasting bellies and dorsums.
The reason is simple. Whether the species is the hunted or the hunter, being able to escape detection is vital to its survival. And ospreys are no different. While hovering above a lake's surface, the bird's white belly blends into the sky above, thus making it difficult for fish and other quarry to see the raptor. Being less visible is key to an osprey's fishing success.
But other adaptations contribute to their amazing abilities, too. An osprey's feet are large and scaly with sharp little spines below each talon. In addition, its toes are the same length, which is different from other raptors, as well as possessing reversible outer toes. These enable ospreys to better grip their slippery and wiggling prey.
The remarkable osprey is a bird worth watching. Striking plumage, vocalizations, hunting style, pair bonding, nests, and parenting are just some of the many fascinating characteristics of this bird of prey. Belonging to the same lineage as hawks, eagles, and falcons, the osprey is nonetheless a different sort of bird as we get out and enjoy the great outdoors.