Horned Lark
Eremophila alpestris [Prairie
Horned Lark]
Contributed by Gayle Pickwell
[Published in 1942:
Smithsonian Institution United States National Museum Bulletin
179: 342-356]
Out at the bleak end of the ecological series of bird habitats,
which begins with the heavy forests and ends with the barrens,
lives America's only true lark. *** Far from the treeless Arctics,
far from the deserts, this lark finds as its barrens the plowed
fields of the Midwest, the tree-denuded, wind-swept hilltops of
the northeastern states, and those peculiarly unnatural artificial
barrens, the hazards of these modern-day golf courses.
If for no other reason than that here is a bird nesting where
no bird has a right to nest, a bird in a niche that demands not
vegetation but lack of it, a bird alone and unique in its nesting
site without a competitor and far out at the end of the series--if
for no other reason than this purely ecological one--the prairie
horned lark invites close study. But if we add to this the fact
that it is a lark, a representative of our only lark, with the
song of a lark, the ways of a lark, and many a habit and
idiosyncrasy peculiarly its own, and that it is an intriguing bird
of the open field, then the bird becomes even more interesting.
The prairie horned lark, because of its tendency to occupy the
most barren regions as its home, interested me very early, for
desultory observations of this bird were begun while still a boy
in eastern Nebraska. The lark nests were found on the ridges of
listed corn and an observation of a song still remains clear and
trenchant. We were shocking wheat, hence it was mid-July, when a
lark was seen climbing the air for his song. We watched him
against the vivid sky during his long minutes aloft; were amazed
by that final headlong drop to earth.
Study of the prairie horned lark was initiated in eastern
Nebraska, continued intensively in northern Illinois (Evanston)
for two years, then transferred to Ithaca, N.Y., and concluded.
***
Courtship.--Prior to the
establishment of well-defined territories, fighting between males
is promiscuous; after that fighting takes place only on territory
boundaries, where two lark areas juxtapose. The males, at the
boundary line, frequently strut before each other and often peck
the ground furiously, like barnyard cocks, but all fighting is in
the air. On a boundary this fighting often results in a curious
game of "tit for tat," as the male larks chase one
another back and forth. Every adventitious lark, wandering into
established territories, is promptly evicted by the male. Such a
bird will leave without protest. So far as noted, the female is
never the direct cause of fighting; in fact fighting is most
frequently noted when the female is brooding and the male is no
longer attending her. Only once was a female noted driving out
another lark, a male. She was defending a recent nestling.
The female has no courting maneuvers and was never observed to
sing. Only once was she seen to importune sexual attention and
then by a crouch and flutter similar to the actions of the English
sparrow. The male struts frequently before the female with wings
dropped, tail spread, and horns up. He will assume this attitude
before another male at the territory boundary.
Nesting.--The literature shows a
surprisingly large range of habitats in which the prairie horned
lark has been known to nest. These habitats, resulting for the
most part from agricultural activity or other human agencies, are
those that most nearly result in barren conditions. It does not
matter that these barrens may be seasonal or otherwise very
temporary, if they are suitable for the initiation of nesting.
That bare ground is the determinant is shown by the fact that
variations of moisture, soil, elevations, and temperature will all
be tolerated in the selection of nest sites. ***
Some typical Chicago marsh in the Evanston region was drained
for a golf course. The course was later cut up into real-estate
subdivisions; sewers were laid exposing a wide area of bare soil
in the streetways; and old sand hazards remained here and there.
This series of activities provided nesting sites for many larks.
More than a score of nests were located in this area (about 90
acres) in 1926. A plot of vegetable gardens bordering this region
on the west, where larks had probably nested for some years, was
also subdivided and the vegetation subsequently neglected. Here
several larks also nested.
The advent of vegetation in both areas and the demand of the
lark for bare ground forced a seasonal succession of horned-lark
breeding sites first from lot surface, to streetway, to sand
hazard, to vegetable garden, in order that each was successively
occupied by verdure.
In Ithaca, N.Y., one nest was located on the overturned sod of
a former hay meadow. Most of the observations there made, however,
were on a tract of ground that was largely fall wheat, partly fall
rye, and the remainder devoted to experimental vegetable gardens.
The growth of the wheat forced the larks from its surface by late
May. The gardens and portions of the fall rye area that were
turned under as green manure remained suitable throughout. Clean
vegetable gardens will always present a considerable amount of
bare soil, and the prairie horned lark is usually able to occupy
such gardens until late in June.
A breeding territory was delimited by a male lark on February
7, 1926, at Evanston, Ill. From his selected territory he could
not be driven. This territory was about 100 yards square. Late
March snows disrupted all territories, and it was not learned
whether the original sites were ultimately resumed or whether the
same territory was maintained through more than one nesting. The
pressure of vegetation in late May and June greatly modified the
territories at Evanston and caused, eventually, the abandonment of
most of those on the erstwhile golf course.
At Ithaca, N.Y., a male lark was forced to mark territory for
the first time on March 13, 1927, though it had undoubtedly been
established some time before this. Territories voluntarily marked
were somewhat larger than those indicated when the birds were
forcibly driven about. The regions of a breeding territory most
frequently occupied were those boundaries that joined the
territories of a neighboring lark.
The territories at Ithaca were much larger than those at
Evanston, possibly because fewer larks attempted to occupy them.
At Evanston they were seldom over 100 yards square, whereas at
Ithaca they ran out to lengths of 300 yards and widths of 200
yards, in March and April. In general all suitable territory was
occupied at Ithaca and most boundaries were established by the
margins of unsuitable areas, though a large amount of suitable
territory, extending beyond, was used only in part by the bird.
Boundaries between males were often definitely established on
ground that had no natural marker whatsoever.
The territory history of three pairs of larks was followed from
March to June at Ithaca. One influence only modified the
territories, namely the growth of vegetation. One territory,
completely on fall wheat, was abandoned by the close of the second
nesting in May. Another territory, in part on fall wheat and in
part on the gardens, was gradually reduced to the gardens, from an
area once 300 by 200 yards to an ultimate area about 100 yards by
50 yards. A third territory, almost entirely on the gardens,
suffered no major reduction. But the owner of this third
territory, which abutted that of the second, gave no ground to the
latter.
Though most of the feeding was done on the nesting territories,
a neutral feeding territory was discovered, and others were
indicated because, now and then, the larks would go off on
purposeful flights entirely out of their areas.
The female would mark the same territory as that marked by the
male, and if anything she was more closely restricted to it than
the male. She selected the nest site with little or no regard to
the center of the area.
The literature contains four February records of nests and many
records of March nests in many states, and two or three records of
nests in July. I have records of nests from about March 21 to July
12, in 1926, at Evanston, Ill.; from about March 11 to June 28, in
1927, at Ithaca, N.Y.
It is suggested that such a strange phenomenon as that of a
passerine bird nesting in March in eastern United States cannot be
easily explained. The bird has too long a nesting season to
explain it on conditions that might exist in early spring alone;
and then, in the range where the prairie horned lark was studied,
nests are frequently destroyed by inclement weather and many young
die of starvation at this season. Since this bird demands barren
conditions, and not verdure, for a nest site, the conditions are
suitable very early, and it is suggested that an early-nesting
physiological cycle may have been acquired in a more propitious
climate and subsequently carried north and east. It is further
noted that O. a. actia of California nests in March where
conditions are quite ideal.
With one exception all of the 14 observed nests of March and
April were not begun until the mean temperature rose above 40o
F. for two or more days in succession. The exception was the
initiation of a nest on the first day that the temperature
rose above a mean of 40o F. Once
weather conditions suitable for the initiation of nesting
activities prevailed, no subsequent weather, no matter how severe,
except deep snow only, would inhibit these activities. Even birds
that had nested in March and whose nests were destroyed by late
March and early April snows, would not renest until weather
conditions were as given, though this necessitated a delay of
nearly three weeks in two cases in Ithaca, N.Y. That this was a
delay caused by weather is easily demonstrated by the fact that an
exceptional case, as noted above, began renesting on a single
suitable day, but two other larks waited two weeks longer for
renesting or until weather again was suitable and for a longer
period. It is known that two of these birds, and probably all, had
former nests. ***
It is suggested that the discovery of nests during nest
building is possible by locating first the calling or singing
male. At this period the male will be attending the female closely
and she will be discovered shortly. The status of nesting can
always be determined by the actions of the female. During nest
building she is very restless, runs here and there, flies up and
away, but shortly returns. Eventually she may disclose the site of
the nest excavation. These reactions are instinctive responses to
the desire for nest concealment. All nest building seems to be
done by the female.
During egg laying the discovery of a nest is at best
accidental. Neither male nor female has been noted to approach a
nest during this period. They express no solicitude beyond that of
nest concealment, thus displaying a remarkable nonchalance,
especially on the part of the female. This reaction is so marked
that an observer can nearly always be assured of the status of
nesting whenever it is noted.
When incubation has begun the behavior is very different, as is
also the behavior after the eggs have hatched. These reactions
will be noted later. During these periods nests may be located by
a systematic search that involves driving the male about until the
female is noted. She will flush from the nest and the male will go
to her. Then a patient watch of the female will, after a variable
length of time, disclose the nest. When young are being fed the
male will, at times, disclose the nest much more quickly than the
female, for he assists in feeding and has nest-concealing
instincts that are very poorly developed. Though the nest of the
prairie horned lark is never concealed from above, it fits its
semibarren environment so closely that a promiscuous search over a
breeding territory is nearly always tiresome and unavailing. An
incubating or brooding lark, as will be discussed later, often
remains close to her nest on a chilly day or very early in the
morning or toward evening. Nests can be found under these
circumstances by a systematic search of likely habitats and so
flushing the bird from the nest.
No evidence of the use of a natural depression was noted either
at Evanston or at Ithaca; all were dug by the female. According to
Sutton (1927) and my own observations of O. a. strigata in
western Oregon, this excavation is dug with both beak and feet.
The nest is constructed usually at the edge or partially under a
grass tuft or clod, which, in the case of the prairie horned lark,
lies most frequently on the west, northwest, or north, possibly
because the cold and violent winds of the early nesting season
come from this direction. The body of the nest consists of coarse
stems and leaves with a finer lining within. The time spent in
nest construction varies from two to four days.
The majority of the nests of the prairie horned lark showed a
variable amount of clods, pebbles, or similar items laid about the
margin usually on the side away from the protective tuft or clod.
These so-called "pavings" were always composed of the
material most easily obtained regardless of its permanency. It is
suggested that the purpose of "pavings," if there is a
purpose, arises from the method of nest construction and from the
desire of the larks to have a bare-ground nest approach.
Eggs.--The egg has a background of
gray with an occasional greenish tinge, which, background is
almost completely concealed with a fine speckling of
cinnamon-brown. The cinnamon-brown often forms a denser ring about
the larger end. The average size was found to be 2.25 cm. by 1.55
cm. The eggs of natural second sets seemed to be a trifle larger
than the first sets of the same individual. The number of eggs per
set varied from two to five; the average was about four, the sets
of fewer numbers occurred early, those of larger number, later.
[AUTHOR'S NOTE: The measurements of 50 eggs average 21.6 by 15.7
millimeters; the eggs showing the four extremes measure 24.6
by 15.5, 23.1 by 17.3, 18.3 by 15.0, and 21.6 by 14.5
millimeters.]
Incubation.--The incubation
period was determined to be 11 days. Only the female incubates.
The male shows little or no solicitude during the incubation
period. The female has a highly developed series of automatic
instincts of solicitude, which are modified by time of day,
condition of weather, and frequency of disturbance. The most
highly developed and probably the most recently acquired of these
has been given the name nest concealment by abandonment, or
casual abandonment. The female leaves the nest, in this
reaction, when an intruder is at a long distance, and flies
quietly away, low against the ground, and does not show other
solicitude for a very considerable period. The distances of the
intruder from the nest during this reaction vary from 25 to 100
yards or often farther, a greater distance, it will be noted, than
would disturb even a timid lark under other circumstances. A
reaction that in many ways is the reverse of this, but still a
marked exhibit of solicitude, is that called distress
simulation. This consists of a precipitate flushing and rapid
flutter over the ground after the nest has been approached
closely. This reaction would be given most frequently on very cold
days, in the dusk of very early morning or evening, and when the
bird was flushed very shortly after she had returned to the nest.
It is certainly more primitive than the first reaction here
described and is probably a culmination of the more frequent
distraction display that most birds present when their nests are
disturbed. Between concealment by abandonment and distress
simulation there occurs a complete gradation, which, since the
reactions are exact opposites in expression, involves a curve that
drops from the first to the zero point and then rapidly ascends to
the expression of the latter. Thus, between the two, lessened
expressions of either reaction would result, with a serious hiatus
midway in which the incubating bird would allow an intruder to
approach closely and then leave without an expression of either
type of solicitude. Experimental flushing of an incubating bird
from a blind showed that the bird, in one case, would give
distress simulation if flushed in an interval that was less than
two minutes from the time of her return; but would give casual
abandonment if flushed after an interval of five minutes. A female
lark, shortly after being forced from a nest, would express her
agitation by aimless ground pecking, and, to be sure, would
eventually be driven by the incubation urge to return to the nest
even though an intruder might be much nearer than he had been when
the nest was originally abandoned. This complex of instincts
involved both the urge to incubate and the urge to protect. The
instinct to protect, by whatever method, would all be overshadowed
in time by the instinct to incubate.
Young.--With the exception of those
nests of early April, in which incubation began before the set was
complete, all young hatched within an hour or two of each other.
The young are fed within an hour or two following hatching. In
most cases the male assisted the female in feeding the young. In
carefully observed cases he visited the nest less often but
brought greater burdens and fed more young at a visit than did the
female. A total number of observed feedings during one day (April
30, 1926) was 108. The male fed 39 times and the female fed 69
times.
Observations of the adults and dissection of a few nestlings
showed that some vegetable matter (weed seeds) is fed early in
spring but that even in March most of the food is animal matter.
Later in the season grasshoppers become conspicuous in the diet.
The adults dig up both cutworms and earthworms.
The male shows solicitude for the nest and its contents for the
first time after the hatching of the eggs. His solicitude is
restricted to calls. The female will leave her brooding in typical
concealment by abandonment when conditions are appropriate as when
incubating; likewise she will go from the young in distress
simulation under conditions as noted previously. Proportionately
the number of concealments by abandonment decreases and distress
simulations increase slightly with young in the nest. Other
reactions, which are various primitive expressions of solicitude,
or intermediates of the two just mentioned, increase
proportionately. Perhaps a return of more primitive instincts
indicates a sum total of greater solicitude. Since the female is
frequently absent from the nest in food foraging, she will come
in, as an intruder approaches, with calls and cries. One or two
references in the literature show that the reactions to dogs is
the same as to man, but that hens are driven off by entirely
different methods.
The larks removed all excreta throughout the full extent of
nest occupancy. Early in the season much of the excreta was eaten
by the adults; later it was dropped to the ground 50 or more feet
away. This seasonal change of habit may have been related to the
available food supply. The instinct compelling excreta removal
proved itself very powerful, at times overcoming strong solicitude
for nestlings and even fear.
The young showed a psychic development closely related to their
rate of growth and not to their age. Young of the same age or but
one day younger than their nest mates often presented a psychic
development two to four days behind them. This was due to uneven
feeding, which occurred frequently early in spring because of
uneven hatching or an inadequate food supply.
Normal nestlings give a food response indiscriminately up to
the fifth or sixth day. Just prior to this time their eyes open.
Following this they respond not at all or momentarily only. They
withdraw at a touch from the hand on the sixth day and sink back
quietly into the nest in crouch-concealment between the seventh
and ninth days. Upon being removed from the nest at this age they
sit quietly upon any object upon which they are placed; prior to
this time they wriggle about when taken from the nest. They leave
the nest on the tenth day and then express fear by hopping and
calling wildly when disturbed. An expression of this type of fear,
prior to the tenth day, would take them from the nest prematurely.
Weight-growth curves show a gradual increase over the first
three days, a very precipitate rise (except for April nestlings)
for the next three or four days, a marked leveling during the
seventh and eighth (in one case the sixth), and a gradual rise
during the ninth and tenth. Nestlings in May grew slightly more in
the same period than a nestling in June and much more than a
nestling in April. This discrepancy of growth seems closely
(though perhaps indirectly) correlated with the temperatures of
these seasons.
A lessening in weight growth occurs, normally, between the
seventh and eighth days. This is brought about by the simultaneous
unsheathing and drying of most of the feathers. On the other hand,
growth in length shows, if anything, an acceleration at this
period due to the extension of the tail. Marked variations in
growth occurred in the various broods measured and in the
different young of the same brood. This was brought about by two
things: the fact that a slight difference in age gave the older
larks a great advantage in securing food from the parents; and the
fact that food was more plentiful later in the season than at the
beginning.
Length-growth curves show a precipitate rise during the first
three days, a slight leveling during the next three days, and a
precipitate rise during the sixth, seventh, eighth, ninth, and
tenth days. The cause for the intermediate leveling is not
understood, but the rise toward the end of the nesting period is
brought about by the growth of the tail.
In the early breeding season the enemies of the young are
weather and a scanty food supply. The weather may result in snows
that bury them from sight. The scanty food supply may result in
the starvation of one or more of the nestlings. Starvation results
from the automatic feeding reaction of the adults wherein the
nestling nearest that part of the nest habitually approached by
the adults will receive the first feeding; if the food is scanty
this bird will receive all or nearly all the food.Only when food
is so abundant that the first nestlings fed do not swallow
promptly will the remainder of the brood be fed. In this case food
is withdrawn from the mouth and put in the next and so on. The
female lark rarely brings more than will go into one mouth; the
male may feed two or more, but never four or five, at a time.
Those young larks that have a few hours' advantage in hatching--a
full day in several cases in the early spring--will have the
advantage in size that will allow them to push to that side of the
nest over which the food always comes. They survive; the others
may perish. Such occurred in many observed nestings in April.
Predacious enemies cause a greater and greater loss as the
season advances into June and July. The optimum season for the
welfare of the young is shown to be May.
One case of cowbird parasitism was observed and followed. A
lark, which hatched before the cowbird, came to maturity. The
cowbird probably did not. It suggested that the early nesting
season and the exposed habitat may mitigate against such
parasitism as may also the early departure of the young larks from
the nest. However, since the adult lark will tolerate the
parasitism and the food of June and July is suitable, other
reasons prevent more extensive parasitism at this later season.
The young leave the nest, normally, on the tenth day, some
three to four days before they can fly. Their protection during
this interval is silence and a very effective "freeze"
or crouch-concealment. Their plumage is remarkably adapted for
this. The actions of the parents, especially the female, with her
abandonment concealment, are calculated to take advantage of the
protective color of nest and young at all ages.
Young leave the nest usually by following a parent that has
brought food. One case was noted wherein a female enticed a
belated nestling from the nest with a food morsel. The young fly
in about five days after leaving the nest. They hop for some days
after nest leaving, whereas the adults walk. This hopping may be
anatomical or an atavism.
Plumages.--The recently hatched
nestlings are rather heavily covered with down, a necessary
protection against sun and cold in their exposed location. The
down is cream-buff in color. At nest-leaving age the young lark is
in full juvenal plumage but presents an appearance quite unlike
that of the adults; each feather of the upper surface has a
triangle of brown at its tip, the under surface is white except
the throat, which is gray. ***
Food.--McAtee (1905), in his
extensive account of the food of the horned larks, writes that in
August and September many grasshoppers are taken (7.1 and 8.9
percent of the total food, respectively) and that weevils
constitute 18 percent of the food in August. He says further that
spiders are taken in every month. The conspicuous weed seeds that
he lists (foxtail grasses, smartweeds, bindweeds, amaranth,
pigweeds, purslane, ragweed, crab and barn grasses) are probably
largely consumed in fall, winter, and early spring. The total of
79.4 percent of vegetable matter taken in the year, as given by
McAtee, is made up largely of these weed seeds. He found about 40
percent of food taken in August to be animal matter, 20 percent
animal matter in September, between 10 and 20 percent in October,
5 percent or less in November, about 2 percent in December, 1.73
percent in January, and 3.11 percent in February. The animal
matter of January and February consisted principally of weevils
and cocoons of tineid moths. Grain, chiefly waste oats, corn, and
wheat, formed 12.2 percent of the food of larks, exclusive of
California forms, and much of this would have been taken in the
period under consideration.
The Main Subdivision at Evanston, where the most extensive
observations were made by the writer, had, in winter of 1925-26,
great quantities of Agropyron repens (quack grass), Seteria
(foxtail), and Amaranthus (pigweed), all of which had been
allowed to mature seeds. Of this the seeds of the quack grass were
eaten first and wherever their long stems had fallen over the
sidewalks the larks would invariably be found in January and
February. When quack grass failed, foxtail was eaten, and lastly Amaranthus
was substituted when no other seeds were available. Once or twice
larks were noted along the roads feeding on the oats of horse
droppings, when snow covered all the weed seed of the subdivision.
And again at Ithaca the compost heaps, put out for fertilizer
along the garden margins, supplied some food when snow lay deeply
over the ground.
At Ithaca, during the spring of 1928, prairie horned larks were
observed feeding on Setaria (March 1), on Ambrosia
artemisiaefolia (April 1). A pair of larks were frightened
away from an arctiid moth larva (Apatensis arge), which I
observed the female dig up (March 3). Finally a few adults were
collected in March at Ithaca (Connecticut Hill), and examination
of the stomachs of six individuals showed that the vegetation
consisted of oats, Setaria, Ambrosia artemisiaefolia,
and waste buckwheat.
In summary of the feeding habits of the prairie horned lark in
autumn, winter, and early spring, all that need be said is that
the bulk of food taken is that of weed seeds, and the animal food,
a much smaller proportion, is almost entirely of those forms
harmful to the agriculturist. The lark, in feeding habits, finds
for his food those things that appertain to the waste lands he
inhabits.
Behavior.--Breeding birds, such
as females in abandonment concealment of the nest, or males in
flight song, exhibit several distinct flights, but at other
seasons the flight is of but one definite character. This is a
choppy undulation brought about by three or four rapid, even
strokes of the wings interrupted by the space of about two beats
during which the wings are closed. A note is uttered on the climb
of each undulation. Or again, on prolonged flights, the character
of the wing beat is as follows: Long strokes are made, one, two,
three (or one, two), with a pause of about one wing beat between
each stroke wherein the wings are folded. Then comes a pause of
the length of one or two beats, with wings folded, causing a drop
in elevation. These repeat. The bird goes thus: jump, jump, jump,
climb (call also), drop, jump, jump, jump.
Voice.--The horned lark, like the
goldfinch, usually advertises itself in flight by a definite,
unmistakable note. Except for an occasional song, this is about
the only sound from the birds in fall and winter. The flight and
call notes are several in number, some of them appertaining more
especially to the breeding season than to wintering birds, and in
that connection they will be considered again. The chief stock in
trade of the lark and the one most commonly heard is p-seet
or merely zeet. It is uttered casually on the climb of the
ordinary undulating flight, especially on long journeys or in
flights of young birds. Adults frequently make low flights over
the ground without uttering a note. This p-seet is
occasionally, sometimes frequently, lengthened to p-seet-it
during the flight. When flushed the note is zu-weet or zur-reet
(long drawn), zeet-eet-it, or zeet-it-a-weet, which
is so high pitched and mournful in character that it makes the
birds indeed a part of the winter's gale that whips them away.
The season of song extended, in the Evanston region, from
mid-January until early July; in the Ithaca region, from
mid-February to late in June. With flight songs used for
criterion, it was found that May was the optimum month. The lark
sings both from the ground and in the air, under all conditions or
weather, though flight songs are most numerous on quiet, mild
days, perhaps a little more numerous when the sky is overcast than
when it is clear.
The most vigorous period of song extends through nest building,
egg laying, and incubation. Perhaps of this period that portion of
it when the female incubates allows most song from the male, since
he attends the female carefully during nest building and egg
laying. The period of least song occurs when the young are in the
nest, for the male assists in feeding. Ground songs are regularly
distributed throughout the entire day; flight songs seem to be
most numerous toward noon or near sundown.
For three months the prairie horned lark is the only singing
bird in the open field; but with the coming and establishment of
other migrants late in May and in June many other songs will be
heard in that region. On June 16, 1926, at Evanston, the prairie
horned lark, the last to begin singing that morning, went into
flight song at 4:00 a.m. However, the lark almost always closes
the singing at night with a long period of recitative which in
mid-June would not close until after 8:00 p.m.
The literature contains several descriptions of the flight song
of the prairie horned lark, that of Langille (1884) seeming to be
most accurate. He describes the flight. The song he describes as
"quit, quit, quit, you silly rig and get away."
This is the intermittent type; nowhere in the literature has a
description of the recitative been found.
Songs are sung from the ground, from a clod or any other slight
elevation, the greatest elevation noted being the roof of a sample
apartment put up on the Evanston area, and from the air. The
ground songs are similar to flight songs though rarely as long or
as systematically presented. The urge to flight song may come at
any time or after an invading male lark has been evicted from
occupied territory. Larks will also go into flight song upon
approach of a human being or they can be forced to go up by
driving them for a time about their territory.
The climb to flight song is distinctive and usually executed
without a sound from the bird. The songs, in the air, are of two
types: a recitative or rapid monotony of notes usually uttered at
the beginning of the flight song, though occasionally at other
periods, never over a few seconds in duration, accompanied by a
steady beat of the wings; and an intermittent song uttered while
the lark sails, about two seconds in duration, followed by a
somewhat longer silent period during which the lark flutters up.
The recitative can be transcribed as pit-wit, wee-pit, pit-wee,
wee-pit; the intermittent as pit-wit, pit-wit, pittle
wittle, little, little, leeeeee. Large circles are described
overhead during the flight song, or the bird heads into the wind
if it is strong. The lark closes flight song by a headlong drop to
earth with wings tightly folded.
Female larks seem to be unaware of the males in flight song,
though other males note the bird overhead. The territory a bird
may occupy in flight song is very extensive. Never were two
visible birds noted in such a performance simultaneously. The one
in the air is left undisturbed though his performance may carry
him over many other lark breeding grounds below. Breeding
territories are not vertical for a distance above a few feet; the
flight song territory is something quite different.
Of several methods employed to determine the heights of larks
in flight song, the most accurate was found to be the use of a
binocular with an ocular scale. It was determined thus, through
measurement of 25 songs, that the lark sings from elevations that
vary from 270 to 810 feet. The average was 464.4 feet. Differences
in height seemed to be individual variations or due to weather.
Thirty times flight songs varied from one minute to five; the
average was 2.34 minutes. Intermittents, regularly given, averaged
11.9 a minute.
An Evanston bird sang from song posts on the ground, which,
during one entire day, varied a few feet from the incubating
female out to 100 yards. The average was 38.66 yards. Ithaca
birds, with bigger territories, sang frequently as far as 150
yards from the nest.
Fall.--Young larks flock shortly
after nest leaving. If the breeding ground has become untenable
owing to vegetation, they seek other regions. Flocks grow larger
through addition of adults in August and September and then
smaller as migration begins. In flight the flocks are
comparatively compact, but they spread widely when the birds
alight to feed or pass the night. During autumn and winter they
occupy regions essentially like those in which they breed in March
and April, that is, semibarren or almost denuded areas, which may
be natural or due to some seasonal condition of agriculture. The
Lapland longspurs and the shore larks (Octocoris alpestris
alpestris) are the only other birds that occupy a habitat with
conditions just like those in which the prairie horned lark occurs
in fall and winter.
Horned Lark*
Eremophila alpestris [Prairie
Horned Lark]
Contributed by Gayle
Pickwell
*Original Source: Bent,
Arthur Cleveland. 1942. Smithsonian Institution United States
National Museum Bulletin 179: 342-356. United States Government
Printing Office
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