Here to return to
THE NIGHT FLYERS
IT is difficult to believe that at times during the season of migration the sky at night is filled with birds from dusk until dawn. Onward they hurry through the darkness. If they see the earth below, it must be too dim to guide them on their journey. Still they find their way just as surely as do those birds which travel by day.
The day flyers, as we have seen, are hardy rovers which are used to the open and do not hesitate to venture far from cover. But the night flyers are the shy, retiring birds of thickets and undergrowth, which rarely go far from their own doorstep. Or, if they live in trees, their flight is usually only from tree to tree. The Thrushes, Warblers, Vireos, and small Flycatchers are all night flyers.
Most of the Snipe live along the beaches or in treeless places, and, as we have learned, they travel by day. But that retiring member of this family, the Woodcock, lives in the dark, shady places and waits for the sun to set before he starts on his journey.
The Snipe and Plover of the open, with their long, pointed wings, need not fear Hawks when they are in the air. But the Woodcock, with his short, rounded wings, would have small chance of escaping if a bird of prey should give chase. For several reasons we know more about the travels of the night flyers than we do about those of the day flyers: first, because many more birds travel by night than by day; second, because practically all birds that fly by night are real migrants; third, because the night flyers seem unable to avoid the lighthouses in their way, and the number killed by striking these beacons erected for man’s safety has given us a vast amount of information concerning birds that travel after dark.
By night as well as day our ears can tell us much about the number of birds that are passing overhead. Indeed, during nights when many birds are flying, we can, from favorable places, such as high hilltops or cities in the birds’ highway, hear their call-notes almost constantly. The hill brings us nearer the birds, and the city lights bring the birds nearer to us. Light seems to attract them as it does moths.
An ornithologist at Madison, Wisconsin, states that on the night of September 14, 1906, no less than 3,800 bird calls were heard from one place. The average was twelve calls for each minute. But at times so many calls were heard that it was evident the air above was thronged with birds.
Study the birds’
time-table, and some night during the season of migration go out of doors and
listen. You may hear the chirp of Warblers, the metallic chink of the Bobolink,
the soft whistle of the Thrushes. Nothing I can write will make you realize
more clearly how wonderful is the journey, through the darkness, of these small
A NIGHT IN A LIGHTHOUSE
It would be a far more thrilling experience to pass a night in a lighthouse when many birds were migrating. Then you would see sights such as you never dreamed of. A lighthouse having what is called “a fixed white light” attracts many more birds than one that flashes, or revolves, or shows a red light.
When the Statue of Liberty was erected on Bedloe’s Island in New York Harbor, it was at first fitted with a strong light which proved a deadly lure to many birds. While it was thus lighted I went with several other ornithologists one night, during the height of the fall migration, to spend the night on the island. Soon after dark we began to hear the calls of passing birds. The air seemed filled with them but they were flying too high to be attracted by the light. All was going well for the night flyers and they were making rapid time on their journey toward the south. But at eleven o’clock the sky became clouded. Distant thunder was heard; soon it began to rain lightly. At once birds appeared about the light. At first there were only a few; but their numbers increased rapidly and within a few minutes there were hundreds of them.
From the feet of the great figure which holds in its hand the fatal torch, the birds, circling in the rays of light above, looked like a swarm of golden bees. In order that we might be among them, we climbed the long spiral stairway, which winds around and around inside the body of the goddess, until we reached her shoulder. Then we mounted the narrow ladder that runs through her up-stretched arm, and came out on the narrow balcony which surrounds the torch. Dazzling white pathways stretched out on every side into the blackness of the night.
The birds came from the north. We could first see them when they appeared at the end of the lane of light. There they paused for a moment. Then, as though drawn toward us by an unseen power, they would dart straight toward the lantern. Some hit parts of the statue or the glass about the light, and two or three actually flew against us as we sat behind the low rail of the balcony. Others, more fortunate, passed onward and, so far as we could see, did not return.
In spite of the great numbers seen about the light, only about thirty hit it and none of these was killed. For every bird seen, thousands were heard passing. It was a scene of indescribable interest. We seemed to have torn aside the veil which hides the mysteries of the night and with the searchlight discovered some of nature’s secrets. What a marvelous number of birds must be traveling when hundreds are killed at a lighthouse on a single night!
Before the first
signs of day were visible the birds had disappeared from about the light. Tired
and hungry, they now looked for food and shelter in some woodland. Surely at
such a time New York City must seem a most unpromising place for breakfast. It
is no wonder then that during the season of migration city parks should be
filled with wing-weary travelers. From the sky they must look like wooded
islands surrounded by a sea of houses. So the migrating birds which in the
country would be scattered over a wide area, in the city are all drawn to the
only places where they may find trees to alight in and insects to eat.
THE NIGHT FLYERS THROUGH A TELESCOPE
It is surprising to look at a drop of what seems to be pure water through a microscope and find scores of little animals swimming about in it. It is even more astonishing to look into the sky at night through a telescope and see that countless numbers of birds are flying through it.
This can be done only when the moon is full or nearly full. Then it forms a background against which the birds are seen to cross between you and its bright, golden face. A small, or low-power telescope is used in order that all the moon may be in the field of the glass. In this way the background is made as large as possible.
At various times and places I have watched the night journeys of birds through a telescope. One night in early September, near my home at Englewood, New Jersey, with a friend, I saw two hundred and sixty-two birds cross the moon between the hours of eight and eleven. Some passed so quickly that they were mere blurs. They were evidently very near. Others were in sight for two or three seconds; the movements of their wings could be seen distinctly. They were undoubtedly a long way off and very high.
Now in order to realize what a very small part we saw of the birds that were traveling, we have only to compare the size of the moon with that. Of all the sky which we see when we look at the moon. Let us imagine that I could have seen just as well everywhere as I did in that long, narrow wedge of air which stretched from the telescope to the moon. What an amazing throng of birds I should have beheld, all hurrying down the air line to their winter homes!
If we knew exactly how far the birds observed were from us, it would be possible to tell how high above the earth they were traveling. Those that passed most quickly were, of course, the nearest and lowest. Probably they were flying at the height of those birds whose call-notes we can hear so plainly as they go over us. This, perhaps, may be anywhere between five hundred and one thousand five hundred feet. But calculations show that those which were farthest away were probably three miles above us. As we go upward from the earth we know that the air becomes thinner and that what is called its pressure grows less. So it is much easier for a bird to travel at a height of two or three miles than near the ground. Beyond a certain height the air would become so thin that the bird could not live. Just how high this is we do not know; with man it is about five miles.
The tops of the highest mountain peaks in the Andes are nearly that height, but the great Condor soars easily far above them. On some of these same mountains small Flycatchers and Humming-birds live the year round nearly three miles above the level of the sea. Thus we know that at even this height the night flyers could travel comfortably.
MORE LIGHT ON THE NIGHT FLYERS
Few bird students have had a better opportunity to see birds on their night flights than was afforded Dr. Witmer Stone in Philadelphia. On the night of March 27, 1906, a great lumberyard in that city caught fire, and like a vast searchlight it showed the bird armies flying overhead. For at least several hours the feathered invaders passed by steadily and at ten o’clock, when the flight was at its height, Dr. Stone estimates that there were two hundred birds in sight at once. “They flew,” he writes, “in a great, scattered, widespread host, never in clusters. . . . Far off in front of me I could see them coming as mere specks, twinkling like stars, and gradually growing larger as they approached until their wings could be distinguished as they passed overhead. . . . Over all the illuminated area and doubtless for a greater distance beyond, they seemed about evenly distributed, those immediately over the flames glowing like coals of fire, those further away appearing silvery white.”
Dr. Stone believes
that most of the birds were Juncos and Sparrows of several kinds and the
discovery of the partly burned bodies of some of these unfortunate night flyers
that had come too near the flames proved that he was correct.
SUGGESTIONS FOR STUDY
How do we know that birds travel at night? Why do some birds migrate only after dark? Mention some birds which travel only at night. Have you ever heard birds calling at night? When? Where? Were they flying over? Were their calls answered? Where is Bedloe’s Island? Who made the Statue of Liberty? By whom was it given to the United States? Have you ever seen bird travelers in city parks? Why should they visit them? Do you know of any parks in which feeding stands and baths have been arranged for the entertainment of bird visitors? In order to understand clearly how small a section of the sky can be examined through a telescope which takes only the moon in its field, draw on the blackboard a diagram representing the moon at one end, a telescope at the other. It is, of course, only through the narrowest part of this area, that nearest the telescope, that birds are visible. How many have been seen through a telescope in three hours? At what height can birds fly? Describe the observations of Dr. Stone.