Fly, dive like a bird in the sky; swim, dive like a bird in water
I've often wondered what it would be like to be a bird. Perhaps it was this desire that compelled me to learn how to fly airplanes, which I once did. Although I have not piloted an airplane for many years, the longing to return to the sky has never waned.
As much as I enjoy flight, my first airplane ride was unusual to say the least. Up into the air I flew, as a passenger, somewhere between 3,000 and 4,000 feet in altitude, inside a small aircraft, enjoying the ride...yet I never landed -- not in the airplane anyway.
Oddly, I jumped -- as in jumping out of the relative safety of the winged machine I was being transported in. From a few thousand feet above the earth I dived, and then floated lazily downward aided only by the sprawling canopy of a parachute gently flapping overhead. It was an exhilarating experience.
These lofty adventures, though grand on every level, was followed by another out-of-world experience where I once swam below the surface of the water, breathing oxygen, swimming and diving and enjoying a medium that human beings have no business experiencing.
Indeed, I have flown and dived like a bird in the sky, and I have swum and dived like a bird in the water, yet not all birds can fly and dive in the sky, and not all birds can swim on and below the water. There are, however, a few avian notables that can and do; and in some case, all of the above.
The first bird that comes to my mind that has the amazing ability to fly, swim, and dive is Minnesota's state bird -- the common loon. Possessing a skeleton dissimilar to other birds adept at flight, the loon is nonetheless a master of both air and water. The bird's bone structure is not to say, however, that it is out of its element when aloft -- loons fly with a command of grace, power, and speed. Common loons routinely reach flight-speeds in excess of 70 miles per hour.
As powerful a flyer as the loon is, the bird is also nearly penguin-like when it comes to swimming and capturing prey within the lakes of northern Minnesota. Loons can dive underwater many dozens of feet, up to 100 feet and more, for as long as ten minutes at a time. The birds are able to do this for a number of reasons.
Most birds' bones are relatively hollow in structure. Hollow bones are lighter in weight and thus, enable birds to accomplish and maintain flight easier. But for loons, having lighter bones would be maladaptive. For these birds, solid and heavier bones are the ticket. Loons are less buoyant with such bones, which enable them to achieve maximum dive depths.
Loons are also able to compress the feathers on their body. Such action effectively squeezes out any air that may be trapped between their densely arranged feathers. Again, buoyancy is reduced. Couple this trick with the structure of their bones and powerful swimming legs located far back on its body, the loon is like an avian torpedo.
Many other birds dive too. Ospreys, or fish hawks as they are sometimes called, are true champion fish catchers. An osprey generally sights its prey while hovering above the surface of the water. It will then drop from the sky, feet-first, to catch a fish. Holding its wings vertically above itself and out of the way, the osprey hits the water with such force and speed that it frequently disappears beneath the surface before emerging with its meal gripped tightly within its sharp talons.
Ospreys also have a unique way of transporting fish. Once in the air and on its way to a feeding site, the bird will usually position a fish headfirst and inline with its own body. Furthermore, the osprey's feet are specifically adapted for fish grabbing. With reversible outer toes and sharp projections on the undersides of their feet, slippery fish aren't apt to "slip away."
Though we don't have brown pelicans in our neck of the woods (our species is the American white pelican) the dives of these birds are worthy to mention. Both pelicans are fish eaters, but the white pelican fishes in a vastly different manner. Unlike its cousin of the Atlantic and Pacific coastlines, the white pelican does not dive. Instead, this bird cooperates with others of their kind by forming lines in the water and herding the fish ahead of them while beating the surface with their wings.
But the brown pelicans' fishing method involves graceful and pinpoint dives that are often performed with other pelicans hunting together. After the pelican has sighted its prey from above the water, it dives headfirst with its bill completely closed. A second before the dive occurs the wings are extended behind the bird. Once underwater the pelican lifts its upper mandible and opens its pouch like a giant scoop, catching the fish at that precise moment.
Other great divers include the belted kingfisher. From heights as high as twenty or more feet, the squat little bird propels straight down, and, with a splash, is almost as quickly back to its perch with a meal. Another amazing diver, oldsquaw, now called long-tailed duck, has been found at impossible depths. Great Lakes fishermen have captured these ducks in gill nets set as deep as 160 to 200 feet!
Incredible diving birds, whether performing their feats in the air, below the surface of the water, or both, exist everywhere throughout the world. From peregrine falcons that dive to speeds of over 200 miles per hour in pursuit of winged prey, to Emperor penguins reaching depths of up to 1,500 feet as they hunt for fish, to the unlikely underwater dives of American dippers underneath swift moving streams; so many birds -- so many swimming, diving and flying birds -- to observe and appreciate as we get out and enjoy the great outdoors.
(Klemek is the DNR Area Wildlife Supervisor in Detroit Lakes. You can contact him at firstname.lastname@example.org)