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IX SOME FAMOUS BIRD
TRAVELERS SURPRISING as are
the travels of the Bobolink there are other birds which make even more
wonderful journeys. When we see how in
our own time the Bobolink has gone West with other pioneers, we can to some
extent understand the manner in which it may have learned the way from its
summer to its winter home. But when birds
migrate regularly to and from islands which are hundreds or even thousands of
miles from the nearest land, we are at a loss to explain how they can have
learned to make so long a journey over seas with no place to rest between the
ports. MIGRATION TO THE
BERMUDAS One February when I
was sailing to the Lesser Antilles, about midway between the Bermudas and Porto
Rico, we passed a beautiful, snowy-plumaged Tropic Bird. The bird was headed
northwest toward the Bermudas, was flying rapidly, and seemed to pay no
attention to our steamer. Doubtless he was
hurrying to join the hundreds of his kind which every year, late in February,
go to the Bermudas to rear their young. Now this little
group of islets is about six hundred miles from the most northern of the
Bahamas and the same distance from the coasts of South Carolina and Nova
Scotia. On every side it is surrounded by water of great depth and there is no
reason to believe that there ever was any land nearer to it than those places
which I have mentioned. So the Tropic Birds
which every February go to the Bermudas could not have learned the route little
by little, as the Bobolinks have crossed the continent. There was no halfway
house. The first journey had to be made just as the latest ones are, in one flight.
We cannot believe
that the first Tropic Birds to reach the Bermudas deliberately set out like
explorers to discover new worlds. Perhaps, like Columbus, they chanced to land
upon the Bermudas just as he did in the Bahamas. We may also suppose that, finding
plenty of fish to live on and holes in the coral rock to nest in, they stayed,
laid their one egg, and raised their downy white chick. When it could join them
they returned to the West Indies whence they had come. Possibly the
parents never flew back to the Bermudas but the chick, prompted by that love of
the land of his birth which plays so important a part in bird migration and
which we shall speak of later as the “homing instinct,” may have flown back to
the Bermudas the following year. “How could he find the way?” is a question
which I will try to answer in a later chapter. That his offspring do find the
way, their return in hundreds every February clearly proves. The Tropic Bird is
not the only migrant which each year visits the Bermudas. Certain shore birds
frequently stop here and, among land birds, the Kingfisher, Yellow-billed
Cuckoo, Bobolink, and Water-Thrush are sometimes found during the fall
migrations. The course of these
smaller birds after leaving the Bermudas is unknown to us. Possibly they may
head due south for Porto Rico, or they may go southwest toward the Bahamas. I have wondered
whether it was a flight of birds from the Bermudas to the Bahamas that Columbus
so fortunately saw when his discouraged sailors were about to mutiny if he
would not turn back home. On October 3 of that eventful year Columbus records
that they were uttering “murmurs and menaces,” but on the following day they
were visited, he writes, “by such flights of birds, and the various indications
of land became so numerous, that from a state of despondency they passed to one
of confident expectation.” Finally, on October
7, birds became so abundant, all flying toward the southwest, that Columbus
changed his course to follow them. So we see that it was due to the migration
of birds not only that Columbus landed in the Bahamas instead of on the Florida
coast, but perhaps that he landed at all. MIGRATION TO HAWAII If we think the
Tropic Bird’s flight of at least six hundred miles across the sea to that little
dot which marks the Bermudas on maps of the Atlantic, remarkable, what shall we
say of the birds which every year visit the Hawaiian Islands? These islands are
said to be farther from a continent than any other part of the earth’s
surface., From California on the east and the Aleutian Islands on the north
they are distant two thousand miles, while Japan is even farther away.
Nevertheless these islands are the regular winter resort of great numbers of
Golden Plover, Turn-stones, Tattlers and Curlew, all of which are believed to
rear their young in Alaska. Here, then, we have
an over-sea journey more than three times as long as that to the Bermudas; and
furthermore it is made to a winter, not a summer home. Unless what is called
the “homing instinct” acts in the fall as well as in the spring and thus leads
birds year after year to the same place in winter just as we know it does in
summer, I can give no reason for the return of these birds each autumn to this
remote group of islands. Whatever may be the
true explanation of the origin and cause of this journey, it is in many
respects the most marvelous of all bird travels. Perhaps the Golden Plovers of
the Atlantic may fly just as far without resting as those of the Pacific, but
if they are overtaken by storms there are numbers of islands scattered along
their route, or they may reach the mainland. But when the Golden
Plover starts on his journey to and from Hawaii he has at least two thousand
miles of water to cross without one single place in which he could take refuge
from a storm. For a true sea bird
like a Petrel, or a Sea-snipe like the Phalarope, such a journey would be an
easy matter. When they were tired they would simply drop down on the water,
tuck their heads under their wings, and thus “ride out” the most violent gale. But the Plover is
believed rarely if ever to rest upon the water. Once under way he must keep on
flying until he reaches his desired haven, or falls exhausted into the sea. Just how long it
takes the Plover to fly two thousand miles no one knows, but Mr. Henry W.
Henshaw who has made a special study of the migration of this bird gives us an
estimate of the probable speed at which it travels. He thinks that Plovers can
easily fly fifty to seventy-five miles an hour, and believes they can travel at
the rate of about forty miles an hour for the entire journey. At this pace the
birds would cover nine hundred and sixty miles a day, and if they steered a
true course they would go from the Aleutian Islands to Hawaii in just two days
and two hours. During this time
they are without either food or rest and we may well believe that when they
land they are not only very tired but very hungry birds. A TWO THOUSAND FOUR
HUNDRED MILE FLIGHT The Golden Plovers
that nest on the shores of the Arctic Ocean spend their winters far from those
that nest in western Alaska and pass this season in Hawaii. The young Plovers
are born in June, and in July, when they are large enough to fly, they all go
to the coast of Labrador. Here, by feasting on crowberries, they become very
fat, and thus store fuel for the long voyage which lies ahead. From Labrador they
cross the Gulf of St. Lawrence to Nova Scotia and then strike out across the
ocean for northern South America, two thousand four hundred miles away. If the weather is fine they are seen passing over the Bermudas and Lesser Antilles. But if the conditions are unfavorable they may rest on these islands or they may seek refuge on the mainland. When they reach northern South America they still have two thousand seven hundred miles to go before they arrive at their winter quarters in Argentina, nearly eight thousand miles from their nesting ground. Here they remain for about four times as long as they do in their nesting resort before beginning their northward journey.
The path they
select in the spring makes the Golden Plover’s migration route one of the most
puzzling things in bird migration. They do not return to the Arctic Regions
over the road by which they came from them, but take a wholly different course.
This leads them first to northwestern South America whence they go through
Central America, or over the Caribbean Sea to the Gulf of Mexico. They then
cross the Gulf, migrate up the Mississippi Valley, and finally reach their
Arctic summer home through British America. There are other
birds which have a double route. For example, the Connecticut Warbler migrates
northward up the Mississippi Valley, and southward along the Atlantic coast. The Black Tern
evidently follows a similar course. In the spring it is rarely seen on the
North Atlantic coast but from August to early October it is not uncommon there.
How can we explain
these double migration routes in which a bird goes south one way and returns
another? Here there is no
gradual advancing followed by retracing of steps, generation after generation,
as there has been, for example, with the Bobolink. These birds never go back
by the route over which they came, and how they have learned either to go or
come I am sure I do not know. THE WORLD’S
CHAMPION MIGRANT What Professor
Cooke well calls the “world’s migration champion” is the Arctic Tern. This bird
looks much like the common Tern which was so nearly exterminated by milliners’
collectors not many years ago, but, thanks to protection on its nesting
grounds, is now becoming more numerous. The Arctic Tern
nests from the coast of Maine northward to the very northern limit of land and
it winters along the borders of the Antarctic Continent. The distance between
its summer and winter home is, therefore, about eleven thousand miles. This
means that one bird flies nearly half-way around the earth and back each year.
This great journey is made by thousands of Arctic Terns; but in spite of their
numbers and the length of their route, few ornithologists have ever seen them
traveling, and no one knows just what route they follow. On the Atlantic coast
they have been seen south of their nesting ground but once. So it seems
probable that, like the Golden Plover, they migrate far out at sea. Professor Cooke
calls attention to the interesting fact that the Arctic Tern “has more hours
of daylight than any other animal on the globe. At the northern nesting-site
the midnight sun has already appeared before the birds’ arrival, and it never
sets during the entire stay at the breeding grounds. During two months of their
sojourn in the Antarctic the birds do not see a sunset, and for the rest of the
time the sun dips only a little way below the horizon and broad daylight is
continuous. The birds, therefore, have twenty‑four hours of daylight for at
least eight months in the year, and during the other four months have
considerably more daylight than darkness.” What wonderful
lives these famous bird travelers live! Almost constantly they are on the go.
The scene is ever changing. Here today, they are hundreds Of miles away
tomorrow. Once the brief nesting season is over they are free for the rest of
the year and in their winter homes may wander whither the fare is most to their
liking. But we must not forget the dangers to which their long journeys expose
them. Thousands fall by the way; and of those that leave us in the fall
possibly not more than half return the following spring. SUGGESTIONS FOR
STUDY Where are the
Bermuda Islands? How far are they from the nearest land? When were they
discovered? To whom do they belong? What bird travelers visit them? Where are
the Bahamas? When and by whom were they discovered? What part did birds play in
their discovery? Where are the Hawaiian Islands? To whom do they belong? How
far are they from the nearest land? What birds visit them in winter? Trace on
the map the migration route of the western Golden Plover. At about what rate of
speed is it believed to travel? At this rate, how long a time would it require
to fly from the Aleutian Islands to the Hawaiian Islands? Trace on the map the
route of the eastern Golden Plover in traveling from its summer home to its
winter quarters; and in returning. In what respect is its journey remarkable?
Mention some other birds which have a double migration route. Trace the route
followed by the Arctic Tern. |
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