Owls Aren't Wise and Bats Aren't Blind (19 page)

THE SAW- WHET OWL

We tend to think of owls as large birds, but they come in all sizes, from the very large to the middle-sized to the tiny—and one of the tiniest is the saw-whet owl
(Aegolius acadicus).
How small is tiny? The diminutive saw-whet stands only seven or eight inches tall and weighs approximately three ounces. It can easily fit in the palm of one’s hand and somehow seems too small to be a raptor like its bigger relatives.

Where other owls appear benign, comical, or fierce, the saw-whet, despite yellow eyes, can only manage to look cute—an owlish version of Tom Thumb. This mien is perhaps reinforced by the fact that the saw-whet is “earless,” with a smooth, rounded head. There is nothing cute about this diminutive owl when it comes to predation, however. Make no mistake, those little talons are strong and needle-sharp, and the tiny beak is perfectly capable of dissecting prey with exemplary efficiency.

Although the saw-whet eats insects and, occasionally, small birds—prey that would seem in keeping with its size—its main diet consists of mice, voles, shrews, and even young squirrels. Consider that a fat meadow vole approximates the weight of the saw-whet itself, and a young squirrel substantially outweighs it, and the rapacious nature of this little owl comes into clear focus.

The saw-whet is primarily a northern owl—resident across southern Canada and southern Alaska, the northern portions of the United States, and south through the Rocky Mountains and along the Pacific Coast to Mexico. Although it doesn’t migrate in the true sense of the word, the population of saw-whets does shift somewhat southward during the winter. In the eastern United States, the saw-whet often winters as far south as the Carolinas; less commonly, it may even be found in winter as far south as the Gulf Coast.

Although this tiny owl is common and wide-ranging, it’s rarely seen for two reasons. First, the saw-whet is almost entirely nocturnal and spends its days roosting mostly in dense evergreens, where its small size and brown coloring render it nearly invisible. Perhaps that’s why I’ve never been privileged to see a live saw-whet. Incidentally, saw-whets are noted for their great tameness when roosting during the day. They seem totally unconcerned by human proximity and reputedly can even be handled at such times.

In partial recompense for never having seen a live saw-whet, I’ve been fortunate enough to have two dead ones brought to me. My first sight of a saw-whet came only a couple of years after I mounted the skunk-scented great horned owl. A lady had found the little thing in her barn, evidently dead from natural causes. I mounted it at her request, constantly amazed that an owl could be so tiny. A second saw-whet was given to me much more recently; it, too, had died of natural causes—very possibly starvation, since it was found in the middle of a severe winter.

The second reason why the saw-whet is so seldom seen is that it’s silent for most of the year. Only with the approach of spring does the little owl vocalize, emitting a sustained series of rapid whistles, most frequently described as a monotonous
tootootootootoo,
well over one hundred times a minute. Clearly, the saw-whet is the Johnny One-Note of the bird world.

To the best of my knowledge, I’ve never heard a saw-whet owl, but an acquaintance told me about her initiation with its “song.” For hours on end, while she worked around the house on an early spring day, she kept hearing a strange and unfamiliar noise. She described it as sounding like a radio test signal—a sustained series of very short, high-pitched beeps—which went on and on until they nearly drove her crazy.

The unfortunate woman began to fear that there was either something wrong with her hearing or that she was losing her mind. Finally, in near desperation, she called in someone else and asked if that person could hear the noise. When the answer was affirmative, she was first greatly relieved and then set about locating the source of the sound. After some effort, and a bit of aural triangulation, she finally found it—a little saw-whet perched demurely in an evergreen tree behind her house.

Like other owls, the saw-whet eschews any nest-building chores. Nesting takes place in a tree cavity, often in holes abandoned by woodpeckers; abandoned flicker nests appear to be a favorite. Nesting can start as early as the end of March, but may be a month or two later, with five or six eggs laid on the floor of the cavity. Incubation takes three to four weeks before the next generation of this minuscule owl hatches.

Stereotypes being what they are, owls will no doubt continue to symbolize all that is wise for many people, but they’re clearly otherwise—far from the brightest of birds. That shouldn’t diminish our admiration for them one whit, however. Quite the contrary, owls have such astonishing abilities as predators that we should view them with respect and wonder. With their wide variety of sizes and habits, and their many amazing adaptations, owls of all descriptions will richly repay any time spent in studying or observing them.

12

Which Is Which? The Heron and the Crane

MYTHS

Herons and cranes are the same thing.

All North American cranes are endangered.

Cranes eat mostly fish.

Both cranes and herons roost and nest in trees.

IN ONE OF THE MOST PREVALENT CASES OF MISTAKEN IDENTITY IN THE REALM OF WILDLIFE, OUR LARGEST HERON, THE GREAT BLUE
(ARDEA HERODIAS)
IS TIME AND AGAIN REFERRED TO AS A CRANE. Over and over I’ve heard people here in the Northeast, for example, call a great blue heron a crane; alas for accuracy, the only cranes known in this region, historically or otherwise, are fire-place cranes and construction cranes!

Perhaps this misidentification isn’t too surprising. To those with only a passing interest in wildlife, there are several similarities between the great blue heron and our North American cranes: both are tall, long-legged, imposing, and most commonly found around water. Although these similarities are somewhat superficial, they can undeniably be misleading. Whatever their apparent resemblance, however, the great blue and the cranes aren’t even closely related, and belong to entirely separate families. As will become evident, their differences are much greater than their similarities.

Most people who are unfamiliar with cranes automatically assume they’re an endangered species. That, of course, is because the splendid whooping crane
(Grus americana)
is indeed endangered; in fact, it was what might be called the original poster child for North American species of wildlife that are endangered or threatened. The sandhill crane
(Grus canadensis),
however, is far from endangered. Some 500,000 migrate annually through Nebraska’s Platte River Valley, while another 30,000 to 35,000 migrate from the western Great Lakes region to Florida.

Whooping crane
(rear)
; great blue heron

A few similarities in general appearance notwithstanding, physical traits are as good a place as any to begin distinguishing between herons and cranes—in this instance, between the great blue heron and the whooping crane. Coloration is a very obvious difference. The great blue is well named for the bluish gray plumage on its body, while the adult whooper is all white except for red around the face and black primary wing feathers (immature whoopers show some rusty coloring). There is, incidentally, a white color morph of the great blue heron, known as the great white heron, but this is found only from southern Florida southward.

If the whooping crane’s vivid red face and the bold contrast of black on white feathers make it one of the most strikingly dramatic of all birds, the great blue offers its own special brand of personal adornment. As the spring mating season draws near, the big herons develop an array of plumes flaring from the lower neck, as well as plumes along the back. At the same time, black crest plumes, starting at the eye, bisect the white face and extend well back beyond the head. Together with black, buff, cream, and reddish brown tones on various portions of the neck, these plumes lend the great blue a rare beauty.

In flight, whoopers are easily distinguished from great blues in two ways. First, a crane flies with its head and neck extended straight forward, while the long neck of the great blue is folded back so that its head is almost between its shoulders. Second, the whooper flies with a quick, distinct emphasis on each upstroke of its wings; in contrast, the great blue flies with a slow, steady, rhythmic wingbeat.

On the ground, the differences in the neck are also highly visible. The whooper’s neck curves down from the shoulders and then upward to the head in a simple U, while the great blue’s neck loops into an S curve, much as it does in flight.

Then there is the matter of the tail assembly. When at rest, the great blue’s wingtips and tail blend together almost seamlessly into a slightly blunt point. The whooper, on the other hand, has long plumes that extend from the upper rear and drape down over tail and wingtips in what is often described as a “bustle” effect.

The voices of the two species are also totally dissimilar. As its name implies, the whooping crane has a high-pitched, rather musical cry. In stark contrast, great blue herons generally manage nothing better than harsh, dismal, and decidedly unmusical croaks. When nesting, they contrive to utter a much wider variety of sounds, but these strange cries could hardly be described as musical, either.

The eating habits of the two species are quite different, too. Herons, although their diet can be quite varied, are preeminently fish catchers. This trait has long been recognized. For example, an English writer in 1579 stated, in charmingly quaint language, “Herones, Bitternes . . . These Fowles be Fishers.” Indeed, so dependent are great blues on being able to catch and swallow large fish that the inability of many juveniles to master this art is considered a major reason why only one in five survives to adulthood.

Patience is a virtue widely urged on would-be Izaak Waltons, and it’s difficult to conjure up a better mentor in this regard than the great blue. Observing this heron at work varies from something akin to watching a video at its slowest possible speed to gazing intently at a still life for an hour or two. A wading heron moves forward, ever so slowly, barely moving one leg at a time, often standing poised on a single leg while it surveys the water for prey. When standing still, the bird freezes into total immobility, anchored stoically in one spot for improbably long periods of time.

There is nothing lethargic about a great blue when it centers a victim in its sights, however. Then, with astonishing rapidity, the elongated neck uncoils, the long, sharp beak cleaves the water’s surface with lightning speed, and more often than not the triumphant heron successfully grasps or spears its meal.

If the prey is small, the heron merely points its bill skyward and gulps it down. A large fish or other sizable prey requires more cautious treatment, though. First the heron must totally vanquish the lively and thoroughly uncooperative prey lately hoisted from its watery domain. In service of that goal, it may repeatedly stab its prospective meal to render it more or less inert. This is by no means the only weapon in the great blue’s arsenal. While watching a great blue fishing in his pond, a friend saw the heron dredge out a bullpout—a small catfish also known as a bullhead or horned pout—about a foot long. The heron then waded to the bank and industriously pounded the fish on the hard ground. It repeated this performance several times until the fish expired, and only then did the bird attempt to swallow it.

The great blue’s seemingly slender neck has an amazing ability to expand so that large fish and other sizable prey can travel from beak to stomach. Nonetheless, swallowing large fish presents a substantial hazard to the inexperienced heron. If the bird attempts to swallow the fish tailfirst, the spiny fins are likely to catch in the bird’s throat, condemning it to a slow and thoroughly unpleasant death. This is only one more of the many lessons the juvenile heron must learn successfully in order to survive.

Although large fish are ultimately the key to their long-term survival, great blue herons indulge in a wide variety of other foods. These include frogs, salamanders, crayfish, and insects, but also encompass more substantial fare, such as the occasional small muskrat or duck. At times, great blues will also seek terrestrial food. Mice, voles, and gophers are typical of this cuisine, but they’ve also been known to seize and devour Norway rats.

If great blue herons are large consumers of fish, cranes most definitely are not. Although cranes will eat fish if they’re readily available, they’re by no means patient fishermen in the mode of the great blue heron, nor do fish make up an appreciable part of their diet. Instead, cranes stalk about in marshes or on prairie land, gobbling up an extensive array of foods. Crustaceans, amphibians, and insects make up a good deal of their diet, but whoopers also feed heavily on grain and new shoots of grass. Mice and other small rodents are also fair game for the whooper.

As previously noted, the sandhill crane is thriving; in fact, it’s so abundant that it’s a highly prized game bird, legally hunted along its fall migration route in the Central Flyway. At this point, the belief that herons and cranes are essentially alike intersects with the notion that all North American cranes are endangered or are like herons. The result is widespread incredulity that sandhill cranes are legal game.

Many people, even when they learn that sandhill cranes are abundant, ask, “But why kill a sandhill? Its flesh must be strong and fishy, so what’s the point?” Again, this demonstrates the confusion between cranes and herons. Herons, if legal to hunt, would indeed taste strong and fishy, because of their diet. Migrating sandhill cranes, on the other hand, feed extensively on grain and other vegetation. As a result, they’re considered a delicacy. I can personally attest to their edibility; I once had the opportunity to sample sandhill crane at a game dinner and found it similar to wild goose—dark, succulent, and extremely tasty, without the slightest hint of any strong, fishy flavor.

A good four feet tall, with a wingspan of about six feet, blue herons are impressively large birds, highly visible and likely to attract the attention of all who see them. They have the additional virtue of being both common and widespread in much of the United States, as well as some of southern Canada. In fact, there are presently estimated to be about 133,000 nesting pairs of great blue herons in North America, with a total population that probably approaches a half-million.