As the final song of the wood thrush is hushed by the gentle flow of darkness, a mysterious quietness stills the wild land. The daytime foragers have sought the quiescence of sleep and the protection of the night’s enveloping shroud. But for the nocturnal creatures, it is the time of awakening, and the brief moments of silence vanish amid the rising sounds of a newborn chorus. For in darkness, as in light, the pulse of life within the natural community continues unabated.
The incessant buzzing and droning of insects fill the night air. Fireflies have turned the dampened meadow into a twinkling fairyland; the enzymes within their bodies have turned on the cold luciferin lights. Beneath the lone mulberry tree in the garden, we pause and listen to the mellow orchestrations of the snowy tree crickets. They are not soloists, but play in unison—the only insects which do so. Their rhythm depends upon the temperature. We count the wing-against-wing sounds for exactly one minute: 128. We divide this number by 4, add 40, and determine the night’s temperature to be 72 degrees. Other insects compete with this novelty orchestra; they buzz, scrape, whir, or drone their songs in an ear-piercing cacophony of vibrations.
But the night does not belong to the insects alone. Nature’s more timid creatures find security in the darkness. The mice, voles, and shrews now venture forth in greater numbers. The cooler night air protects certain reptiles and amphibians from excessive body evaporation. The cottontail rabbit leaves his hide to mate and to feed on the fresh clover and plantain, but the night is damp and still; his scent is followed more easily by the hunting fox. The raccoon, opossum, and skunk are astir, and the muskrat and the mink forage along the water’s edge. The deer browses throughout the night.
Birds, too, have a particular role to play in this nighttime drama. The black-crowned night herons have left the seclusion of their daytime roosts. Their familiar “quock” can be heard as they fly overhead en route to favorite hunting areas. Nighthawks and whip-poor-wills have replaced the swifts and swallows; the relentless pursuit of flying insects continues. The most feared of all nighttime creatures, the owls, have relieved the day-flying hawks of their predacious task. They glide over field and forest as silently as a passing shadow.
The high-pitched insect orchestra is joined by other stars on the nighttime circuit. From the low wetlands come the more profound chords of the batrachian choir. The gray tree frog trills a musical obbligato, and the great basso profundo, the bullfrog, provides a rhythmic accompaniment of “more rum, more rum, more rum.” A discordant note is sounded as an owl screeches defiance at a territorial intruder. But the exhilaration of the night is unrestrained. The solo of the field sparrow descends the scale; the chat whistles; the mockingbird mimics the performers. And from across the pond comes the hysterical laughter of the gallinule, as if the whole performance were a joke.
The night is dark, but the night lives.
Owls are the silent marauders of the night. They hunt, and they kill. But this is an essential part of maintaining a functional equilibrium in the outdoor community. They are chiefly rodent eaters, and without this night and day predation by the raptors, the natural environment could suffer from drastic ecological changes. Rodents are prolific breeders, and lacking natural controls, their numbers could soon multiply to devastating proportions. Considering man’s interests, owls are among the most beneficial of all bird species, yet they are still persecuted through ignorance and superstition. In addition to rodents, owls do capture a number of other small mammals, reptiles, amphibians, insects, and birds. But we must remember: predators are present in numbers proportionate to the available food supply.
There are eight species of owls that can be considered residents of the eastern United States; four are “eared” (feather tufts), and four are round-headed. They are listed in the table on this page, together with aids to their identification. All have large heads and big eyes, and appear to be neckless. The best chance for visual observation is at dusk.
Owls are most active at night, secretive, silent-winged, and often quiet except during the nesting season. This combination of factors makes them more difficult to observe than most other birds. If you want to find owls, other than just accidentally flushing an occasional one, you must know something about their preferred habitats and the telltale signs of their presence.
Always investigate a flock of noisy crows. They seem to delight in tormenting a sleeping owl—especially the great horned. And with just cause, I am sure, because the great horned owl can cause quite a ruckus amid roosting crows. Many a great horned has eaten crow.
Many times, the screech owl will rest in whatever dense cover is nearby when it finishes foraging for the night. Its presence in a decorative evergreen, thick vines, or other heavily shaded spots about our gardens and orchards is frequently revealed by mockingbirds. Once the resting owl is discovered, it is subject to the continuous scoldings and attacks of the wrathful mockers. Yet this little owl is reluctant to leave its daytime perch, not because it cannot see to do so, for owls can see exceedingly well during daylight hours, but because it would be subject to vicious attacks while in flight and at its next resting spot. For this reason, it is often possible to observe the screech owl quite closely during the daytime.
Evergreens, singly or in a cluster in a predominantly hardwood forest, provide an island of refuge for the woodland owls. Here you may find the great horned, the barred, or a number of long-eared owls. Look for their white splashings, and search the ground for pellets, fur, and feathers. If the evergreens are isolated stands, and you do not find any of these telltale signs beneath them, you can be reasonably sure there are no owls in the area.
Check any large tree (dead or live) that has one or more natural cavities; it may be a nesting tree or a roosting tree. Again, look around the base of the tree and beneath any logical perch for droppings and pellets. If there are indications that owls are present, watch the tree at dusk. It may be an ideal spot for some intensive study. Also, be sure to investigate the area beneath any large nest. Although most owls prefer to nest in cavities, lacking these, they often will appropriate old nests previously inhabited by hawks, crows, or squirrels.
The resting habits of woodland owls vary somewhat. In addition to the screech owl, the great horned and the barred owls may change their resting sites from day to day. But the tiny saw-whet will return to the same bush or limb on succeeding days until it is no longer satisfied with the feeding area. Saw-whets are quite tame, and often can be picked up by hand.
Look for the short-eared owl over marshes, pastures, and sand dune country. It hunts day or night, but is seen most often during the evening and early morning hours. When hunting, it flies just a few feet above the grass and sedges. The more slowly the owl flies, the better its chances are of spotting and capturing an unsuspecting mouse. To maintain a minimum flying speed, it dips and turns, gaining some lift with each erratic maneuver. It will also sit on a post or other low perch and watch a mouse runway in a catlike manner. You can sometimes flush the short-eared from tall grass by making a sharp loud noise, such as clap-ping your hands or closing your field guide with a sharp “bang.” This owl nests and roosts on the ground. Occasionally, resting short-ears will seek the protective cover of available evergreens.
Barn owls are strictly nocturnal, and they are seldom discovered during the daytime. They shun the bright daylight and seek protection in the darkness of old buildings, barns, silos, church steeples, mine shafts, caves, tunnels, and tree cavities. These places are also favored for nesting. Barn owls hunt over open country and are quite tolerant of human habitation. They are chiefly rodent eaters—beneficial friends of the farmers.
Usually, barn owls are found accidentally. Someone discovers a nesting site, and the word soon gets around. If the owls are not disturbed unduly, the site will be used year after year. There are records of the same site being used for a century or longer.
Keeping a nighttime vigil with a family of barn owls is a most interesting experience. It becomes a bit eerie at times as the night’s quietness is broken by rasping screams, discordant clackings, the stuttering “ick-ick-ick” of approaching adults, and the contentious hissing of the young. A strong flashlight aids in observation, but it should be used sparingly.
Your best chance of seeing burrowing owls in the eastern part of our country is in central and southern Florida. Look for them around the perimeter of airports, or in the open flatlands of cattle ranches. They can be seen sitting next to their burrows, or on a post, nearly any time of the day, but they are most active during early morning and evening hours. They feed mostly on night-flying beetles and small rodents. Burrowing owls have the peculiar habit of bobbing or bowing when they become concerned about the intentions of the observer.
Owls will respond to the calling methods described elsewhere in this chapter, especially during the nesting season, when they are concerned with the protection of established territories. The calls of owls are distinct and not very difficult to imitate.
First, study the calls and learn to imitate them with a reasonable degree of accuracy. This can be done by listening to the actual calls at night or to recordings. Then select an area where you have heard owls call, or have seen signs of their presence. Seclude yourself in some cover, or stand against the trunk of a large tree. You are now ready to call Otus and Bubo, or other members of this night-roaming clan. If you keep still, don’t be surprised if the investigating owl comes quite close—perhaps closer than you would like. This ruse will work as well during the day, particularly in the nesting territory of the great horned owl.
Owls have an exceptionally keen sense of hearing, and can be lured quite close with high, squeaking sounds that resemble the distress call of a rodent or some other creature.
Owls are an exemplary illustration of adaptation. Every detail of their physical structure contributes to their success as nighttime hunters. Their bodies are light in weight, softly feathered, and aerodynamically designed for swift and silent flight. The eyes are large, with exceptional light-gathering capacity. The eyeballs are elongated and elastic, permitting instantaneous focusing on close or distant objects; pupils can be opened or closed for proper adjustment to light intensity, much like the lens of a camera. The eyes are fixed in a straight-ahead position (which undoubtedly provides good binocular vision and exceptional depth perception), but this is compensated for by extra neck vertebrae which enable owls to turn their heads in an arc of more than 180 degrees.
The hearing of owls is so keen that they can capture by sound alone a mouse hidden beneath the leaves of the forest floor. (This has been proven with captive owls.) The ears (not to be confused with the feathered tufts) lie beneath the facial disk, and face forward. A funnellike feather covering of the ears in many species helps in gathering sounds.
Being largely carnivorous, owls have long, sharp, strong claws for grasping and holding their prey. Their beaks are heavy and hooked for the purpose of tearing. Beetles and small mammals are swallowed whole by adult birds, usually head first. Large mammals are torn or pulled into bite-size pieces. This, of course, is necessary when feeding the very young.
The eggs of owls are white. There is no need for protective coloration, because incubation begins as soon as the first egg is laid. The number of eggs varies from two or three for the great horned and barred owls, to as many as five to eleven for the barn owl. Since incubation begins immediately, there is often a difference in the size of the fledglings. This becomes more noticeable as the young grow larger. If there is ample food available, all may survive. If the food supply becomes relatively scarce for some reason, the older and stronger fledglings will dominate the feeding, and the weaker ones may not survive. This is one of nature’s ways of ensuring the survival of the strongest, and of adjusting the surviving numbers to the carrying capacity of the land.
As the owls maintain their constant vigil over forests, fields, and meadows, other segments of the outdoor community are exposed to the forays of additional avian hunters in the night. Whip-poor-wills, chuck-will’s-widows, and nighthawks resume their aerial patrols; night herons stalk along the edges of ponds and streams; the woodcock and the snipe probe for earthworms in the mud flats and bottomlands.
Nighthawks make their appearance with the setting of the sun. They feed strictly on airborne insects, and their erratic flight gyrations can be observed over both city and country. Originally, they nested on barren ground and pebbly beaches. (The last ground nest that I observed was in the middle of a cow path in an abandoned pasture.) With the advent of flat gravel roofs on many of our town and city buildings, nighthawks accepted these new man-made “beaches” as ideal nesting sites. They are disturbed less often there, probably, than on the ground. Two eggs, mottled to blend with the background, are laid directly on the gravel, without any supporting nesting materials.
Whip-poor-wills and chuck-will’s-widow are more nocturnal, and they, too, feed on the wing, but not exclusively. Their exceptionally large mouths (opening to 2 inches) are used as scoops when flying through swarms of mosquitoes or other insects. Stiff bristles on both sides of their mouths help funnel the insects into the wide openings. Both species prefer to lay their two eggs on the shadowy, dappled forest floor.
With the diminishing light of the day’s ending, there is a “changing of the guard” among the herons. As the common egrets and the little blue herons return to their communal roosts in scattered flocks, the night herons can be seen heading toward the fresh-water swamps and tidal marshes, either singly or in small, loose flocks. There is an abundance of food to be harvested—minnows, frogs, toads, aquatic insects, crayfish, and other crustaceans. Night hunting is easy along the water’s edge during the season of proliferation.
Even in the darkness of night, every facet of the outdoor community is involved in the continuous struggle for the energy of life. This struggle cannot stop, for the survival of all species depends upon the continued functioning of a dynamic pattern, developed over millenniums.
A number of birds sing at night, but surely the mockingbird is the lead chorister of all the nighttime singers. He is a mimic and a clown. His exultations bubble forth in endless profusion both day and night. His ecstasy reaches its zenith on moonlit nights during the mating season. It is then that he sings incessantly from your TV antenna or the utility wires outside your bedroom window. He denies you sleep, for his song does not have the soothing qualities of a lullaby. It is loud, ebullient, and so intriguingly melodious that it demands your constant attention. His amorous antics are displayed with equal exuberance. Often while singing, he will spring into the air, do a complete somersault, and return to his perch without missing a single note. At times, the fervor of his courtship seems to reach an exhausting pinnacle, and he will flutter to the ground on stiffened wings.
Perhaps it is the constant rejoicing of the mockingbird that challenges other songsters to emulate his nightly performance. The yellow-breasted chat is a versatile night singer, and often is credited with being quite a mimic. Actually, I think its seemingly endless conglomerate of vocal noises unavoidably includes some notes or calls identifiable with other species. I believe this to be true of the catbird, also—an occasional night singer. The field sparrow joins the night chorus with a single hurried trill as though it had been awakened suddenly and wanted to announce its presence. The grasshopper sparrow is another night singer, but its high-pitched buzz can be mistaken for an insect by the untrained ear. In heavily grassed areas, the quick “flee-sic” of the Henslow’s sparrow can be heard sometimes at night. And down in the marsh, we can hear the chatterings of the marsh wrens.
The whip-poor-will and the chuck-will’s-widow enunciate their names so clearly and vigorously that they are immediately recognizable. The whip-poor-will’s call consists of three distinct syllables, with the accent on the first and last syllables (“whip’-poor-weel’ ”). The chuck-will’s-widow’s call is four-syllabled with the accent on the “wid” (chuck-will’s-wid’-ow”). The “chuck” is often inaudible when the bird is not close to the observer. While there is considerable variation in the frequency and rapidity of their calls, both species have a habit of embarking on a series of consecutive calls, as though they were competing for the endurance record of their respective species. Alexander Sprunt, Jr., noted ornithologist from Charleston, South Carolina, once counted a sequence of 834 continuous calls by the chuck-will’s-widow. It is not uncommon for the whip-poor-will to repeat its name 100 times or more in rapid succession.
The most fascinating ritual of all the night performers is the aerial courtship flight of the woodcock. Every spring, hundreds of birders go afield with the hope of witnessing this exciting show; some are successful, but many are disappointed. If you lack an experienced birding friend who can tell you when and where to go, the following points will increase your chances of success.
• The aerial performances take place during the periods of mating and incubation. This can be as early as mid-winter in northern Florida and Alabama, and as late as early May in Maine. March and April are the most likely months for most of the East. Through friends or literature, determine the time for your area.
• During the day, locate what you believe to be the best possible habitats—alder bogs, brushy meadows, or bottomlands with low stands of red maples, willows, buttonbush, and similar wetland plants.
• Performances begin shortly after sunset, but will continue into the night when the moon is bright. Select an observation spot where you have a good view of the sky above the bog or meadow. (It is usually impossible to see the preliminary strutting on the ground.)
• Listen! Listen for the giveaway “peent.” It will remind you of the “peent” call of the flying nighthawk. Once you hear this, you have reasonable assurance the performance is about to begin.
This is what you will see and hear (based on personal observations in an alder bog along the Machias River in Maine).
The “peent” was repeated several times, and twice I heard a low, guttural, froglike call. (I’ve no doubt the male was strutting in his most pompous manner for the benefit of his mate, but I could not see this owing to the dim light and thick undercover.) Then a batlike silhouette rose from the alders and began circling higher and higher. All the while, I could hear a whistling sound that seemed to vibrate in the still night air. As the bird gained altitude, the rapidity of the whistling (made by the wings’ outer primary feathers) continued to increase until it ended in a blurred twitter at the climax of the bird’s ascent, a height of 200 feet or more. The woodcock circled the area twice and then began to spiral downward, but now his song was a sweet, warbling exclamation of his devotion. It continued intermittently until he was a few feet above the alders. He landed at his point of departure, and immediately resumed his “peent” call. Within two or three minutes, the display was repeated. As I retired to my tent on a high bank along the river, I could hear the courtship performance of the woodcock continue on into the night.
For those of you who would venture afield at night, there awaits a new world of mysterious and enchanting sounds that add the elements of surprise and intrigue to bird watching. The eerie hoot of an owl permeates the darkness with a haunting mysteriousness that will set the mood for the night. A strange winnowing high in the air above the meadow tells you the snipe has returned. A “wak-wak-wak” sound from the marsh causes you to wonder, and the “squawk” of a surprised heron startles you. In the South, the “kuk-kuk-kuk” of cackling coots, the frenzied laughter of gallinules, and the wailing cry of the night bird, the limpkin, remind you of faraway jungles. But there is one night call you never will forget. It is a call from the wild north country—the resonant cry of the loon echoing across a spruce-bordered lake. This is a call that embodies the spirit of wildness and freedom—a call that lures you northward again and again.
During the height of spring and fall migrations, there is a constant movement of birds both day and night. Hawks, falcons, herons, swifts, and hummingbirds are daytime travelers. The migratory flights of geese, ducks, loons, gulls, terns, and shore birds can be observed day or night. But the great majority of our songbirds do their most extensive traveling in the protective hours of darkness. In the daytime they rest, feed, and renew their energy for the continuing journey.
On nights when migrations are at their fullest, there are many more birds in the air than we realize—hundreds of thousands of them at the same time. Many of these night migrants can be observed through a spotting scope as they pass the face of the moon. The first systematic approach to obtaining practical figures that would indicate the density of night migrants on a nationwide basis was conducted by Louisiana State Universtiy in the 1950’s. In October, 1952, more than 1,500 “moon watchers” manned nearly 700 observation stations throughout the country. The numbers and directions of flight silhouettes against the moon were recorded and reported on special forms. Then through a series of complicated formulas, involving time, location, angles, a constantly moving moon, etc., it was possible to express the results in a theoretical total indicating the number of passing birds per mile of front per hour. The following examples will give you the number of birds (to the nearest hundred) passing a mile front during the hour between 9 and 10 o’clock on the night of October 3, 1952, for the stations indicated: South Hadley, Massachusetts, 2,400; Brooklyn, New York, 1,600; Moorestown, New Jersey, 4,600; Charlotte, North Carolina, 8,600; Robins A.F.B., Georgia, 4,100; Pensacola, Florida (October 2), 28,200.1
This concerted effort, under the supervision of Louisiana State University, gave us not only the first mathematical deduction of our migration traffic rate and density, but it did much to promote the interest of moon watching among amateur birders.
Moon watching is easiest and most enjoyable when the moon is full, or nearly so. During this period you have the largest area to observe, and the complete circular shape of the moon simplifies the recording of flight directions on a clock-face basis. Past observations indicate that the largest number of birds is on the move during the middle of the night.
The place of observation should be an open area where you can follow the course of the moon without the interference of trees, buildings, or other obstructions. Avoid areas where street lights or automobile headlights interfere. The quieter the area, the better will be your chances of hearing and identifying flight calls. Within city limits, flat-roofed buildings are usually the best locations for observation stations. Of course, moon watching will be most exciting if your point of observation happens to be on a major flyway; but this is not essential. For just the fun of it, your own backyard may provide all the excitement you wish. Certainly the results will be of greater personal interest.
The first requisite of moon watching is the comfort of the observer. It is impossible to maintain continuous or accurate observations if you have to keep twisting your head or body to see through the scope. You can’t operate from a standing position except for momentary sightings. These are the reasons for using a lawn chair and a pillow. An adjustable, aluminum-framed, webbed lawn chair is ideal; it is light in weight and folds for easy transportation.
Moon watching is much more fun if the station is manned by two or more people. In fact, if accurate records are to be kept, this is almost essential. One person acts as observer while another does the recording. The following steps will help you get set up in an efficient manner.
• Face your chair toward the moon. If the moon is kept slightly to the left of the chair, you can watch it for a longer period of time without having to readjust the chair’s position.
• Mount the scope securely on the tripod. For best results, make sure the eyepiece does not exceed 20x. Greater power will not permit you to view the entire moon at one time, and the light collected is too brilliant for continuous viewing.
• Position the tripod over the chair so that the ocular is somewhere near the desired viewing position. Depending on the leg spread of your tripod, you may have to invert the center post to get the scope low enough.
• The observer (now in position) makes the final adjustments to bring the ocular to the viewing eye. A pillow beneath the observer’s head adds comfort and a certain degree of stability, and it can be used to raise or lower the head slightly for this final adjustment.
• Focus on the moon. Start with the moon at the left edge of your field of view. You can make continuous observations until the moon begins to move off the right edge of the field.
• Readjust the chair’s position until the moon is again at the left edge of the field of view.
Passing birds will appear as small, fast-moving silhouettes against the bright background of the moon. Some will be recognizable as to families, but most will not. Some birds will be in sharp focus, and others will seem hazy. Most crossings are made in a fraction of a second, the speed depending largely on the bird’s distance from the scope—the nearer the scope, the smaller the viewing plane.
Record keeping is a matter of choice. You may want to moon-watch for the pure fun of it, or you may be interested in accumulating some comparative records for your area. Picture the moon as an imaginary clock face, 6 o’clock being at the bottom nearest the horizon. The observer will call out the passing of birds—for example, “Bird 9 to 3.” This means a bird is passing the face of the moon in a direction from 9 o’clock to 3 o’clock. The recorder makes this notation. Sightings are usually blocked into time periods of 30 or 60 minutes. Field notes can be transferred to circular diagrams with arrows indicating directions and numbers.
With experience, you will be able to recognize certain passing silhouettes and identify some of the chips and pipes of the flight calls. Moon watching adds a new dimension to birding by providing a visual conception of the magnitude of migration.
1 Robert J. Newman and George H. Lowrey, Jr., Selected Quantitative Data on Night Migration in Autumn (Baton Rouge, La.: Museum of Zoology, Louisiana State University, 1964).