Transcriber Note
Text emphasis is denoted as _Italics_.
U.S. DEPARTMENT OF AGRICULTURE
Farmers’ Bulleting
630
Contribution from the Bureau of
Biological Survey, Henry W. Henshaw, Chief.
February 13, 1915.
SOME COMMON BIRDS USEFUL TO THE FARMER.
By F. E. L. Beal, _Assistant Biologist_.
Note.—The habitat, food habits, and economic relation to agriculture
of more than 50 birds common to farming sections are discussed in this
bulletin. It supersedes Farmers’ Bulletin 54.
CONTENTS.
Page.
The bluebirds 2
The robins 3
The titmice 4
The wrens 6
Brown thrasher 7
Catbird 7
The swallows 8
Towhee 9
The sparrows 9
House finch 11
The grackles 12
Brewer blackbird 12
Baltimore oriole 13
Bullock oriole 14
The meadowlarks 14
The red-winged blackbirds 15
Bobolink 17
Crow 17
Blue jay 19
Pacific coast jays 20
The phœbes 21
The kingbirds 23
Nighthawk 24
The woodpeckers 25
The cuckoos 27
INTRODUCTION.
Whether a bird is beneficial or injurious depends almost entirely
upon what it eats. In the case of species which are very abundant, or
which feed to some extent on the crops of the farmer, the question
of their average diet becomes one of supreme importance, and only by
stomach examination can it be satisfactorily solved. Field observations
are at best but fragmentary and inconclusive and lead to no final
results. Birds are often accused of eating this or that product of
cultivation, when an examination of the stomachs shows the accusation
to be unfounded. Accordingly, the Biological Survey has conducted for
some years past a systematic investigation of the food of those species
which are most common about the farm and garden.
Within certain limits birds eat the kind of food that is most
accessible, especially when their natural food is scarce or
wanting. Thus they sometimes injure the crops of the farmer who has
unintentionally destroyed their natural food in his improvement of
swamp or pasture. Most of the damage done by birds and complained
of by farmers and fruit growers arises from this very cause. The
berry-bearing shrubs and seed-bearing weeds have been cleared away,
and the birds have no recourse but to attack the cultivated grain or
fruit which have replaced their natural food supply. The great majority
of land birds subsist upon insects during the period of nesting and
moulting, and also feed their young upon them during the first few
weeks. Many species live almost entirely upon insects, taking vegetable
food only when other subsistence fails. It is thus evident that in
the course of a year birds destroy an incalculable number of insects,
and it is difficult to overestimate the value of their services in
restraining the great tide of insect life.
In winter, in the northern part of the country, insects become scarce
or entirely disappear. Many species of birds, however, remain during
the cold season and are able to maintain bike by eating vegetable
food, as the seeds of weeds. Here again is another useful function of
birds in destroying these weed seeds and thereby lessening the growth
of the next year.
In the following pages are discussed the food habits of more than
50 birds belonging to 12 families. Many are eastern forms which are
represented in the West by slightly different species or subspecies,
but unless the food habits differ they are not separately described.
In some cases specific percentages of food are given, but for the most
part the statements are made without direct reference to the data on
which they are based.[1]
[1] Farmers’ Bulletins describing the food habits of wild birds and
groups of birds, or presenting methods of attracting them about our
homes have been issued as follows:
54. Some Common Birds in their Relation to Agriculture, by F. E. L.
Beal, 1897. The present bulletin is largely a revision of this
bulletin and supersedes it.
383. How to Destroy English Sparrows, by Ned Dearborn, 1910. This
bulletin has been superseded by Farmers’ Bulletin 493.
450. Our Grosbeaks and Their Relation to Agriculture, by W. L.
McAtee, 1911.
493. The English Sparrow as a Pest, by Ned Dearborn, 1912.
497. Some Common Game, Aquatic, and Rapacious Birds in Relation to
Man, by W. L. McAtee and F. E. L. Beal, 1912.
506. Food of Some Well-known Birds of Forest, Farm, and Garden, by
F. E. L. Beal and W. L. McAtee, 1912.
513. Fifty Common Birds of Farm and Orchard, prepared under the
direction of Henry W. Henshaw, 1913. This bulletin was issued
with illustrations in color, and the demand for it was so
enormous that it is no longer available for free distribution.
Copies may be had for 15 cents (postage stamps not accepted) of
the Superintendent of Documents, Government Printing Office.
609. Bird Houses and How to Build Them, by Ned Dearborn, 1914.
621. How to Attract Birds in Northeastern United States, by W. L.
McAtee, 1914.
The parts of this bulletin relating to the crow and blue jay were
contributed by E. R. Kalmbach, and the discussion of the nighthawk is
by W. L. McAtee, both of the Bureau of Biological Survey.
THE BLUEBIRDS.
[Illustration: Fig. 1.—Bluebird. Length, about 6½ inches.]
The eastern bluebird[2] (fig. 1), one of the most familiar and welcome
of our feathered visitors, is a common inhabitant of all the States
east of the Rocky Mountains from the Gulf of Mexico to southern Canada.
In the Mississippi Valley it winters as far north as southern Illinois,
and in the East as far as Pennsylvania. It is one of the earliest
northern migrants, and everywhere is hailed as a harbinger of spring.
Very domestic in habits, it frequents orchards and gardens, and builds
its nests in cavities of trees, crannies in farm buildings, or boxes
provided for its use.
[2] _Sialia sialis._
The bluebird has not been accused, so far as known, of stealing fruit
or of preying upon crops. An examination of 855 stomachs showed that 68
per cent of the food consists of insects and their allies, while the
other 32 per cent is made up of various vegetable substances, found
mostly in stomachs taken in winter. Beetles constitute 21 per cent of
the whole food, grasshoppers 22, caterpillars 10, and various other
insects 9, while a number of spiders and myriapods, about 6 per cent,
comprise the remainder of the animal diet. All these are more or less
harmful, except a few predacious beetles, which amount to 9 per cent.
In view of the large consumption of grasshoppers and caterpillars
we may at least condone this offense, if such it may be called. The
destruction of grasshoppers is very noticeable in August and September,
when these insects make up about 53 per cent of the diet.
It is evident that in the selection of its food the bluebird is
governed more by abundance than by choice. Predacious beetles are eaten
in spring, as they are among the first insects to appear; but in early
summer caterpillars form an important part of the diet, and these are
later replaced by grasshoppers. Beetles are eaten at all times, except
when grasshoppers are more easily obtained.
So far as its vegetable food is concerned the bluebird is positively
harmless. The only trace of any useful product in the stomachs
consisted of a few blackberry seeds, and even these probably belonged
to wild rather than cultivated varieties. Following is a list of the
various seeds which were found: Blackberry, chokeberry, juniperberry,
pokeberry, partridgeberry, greenbrier, Virginia creeper, bittersweet,
holly, strawberry bush, false spikenard, wild sarsaparilla, sumac
(several species), rose haws, sorrel, ragweed, grass, and asparagus.
This list shows how little the bluebird depends upon the farm or garden
to supply its needs and how easily, by encouraging the growth of some
of these plants, many of which are highly ornamental, the bird may be
induced to make its home on the premises.
Two species of bluebirds inhabit the Western States—the mountain
bluebird[3] and the western bluebird.[4] In their food habits they are
even more to be commended than their eastern relative. Their insect
food is obtainable at all times of the year, and the general diet
varies only in the fall, when some fruit, principally elderberries,
is eaten, though an occasional blackberry or grape is also relished.
In an examination of 217 stomachs of the western bluebird, animal
matter (insects and spiders) was found to the extent of 82 per cent
and vegetable matter to the extent of 18 per cent. The bulk of the
former consists of bugs, grasshoppers, and caterpillars. Grasshoppers,
when they can be obtained, are eaten freely during the whole season.
Caterpillars also are a favorite food and are eaten during every month
of the year; March is the month of greatest consumption, with 50 per
cent, and the average for the year is 20 per cent. Two stomachs taken
in January contained 64 and 50 per cent, respectively, of caterpillars.
Beetles also are eaten and comprise mostly harmful species.
[3] _Sialia currucoides._
[4] _Sialia mexicana subspecies._
The vegetable matter consists of weed seeds and small fruits. In
December a few grapes are eaten, but elderberries are the favorites
whenever they can be found. It is only when these are in their greatest
abundance that vegetable exceeds animal food.
THE ROBINS.
[Illustration: Fig. 2.—Robin. Length, about 10 inches.]
The robin[5] (fig. 2), in many parts of the country one of the most
cherished of our birds, is found throughout the States east of the
Great Plains, and is represented farther west and south by slightly
different subspecies.[6],[7] It breeds far north through Canada,
and is found even in Alaska. Although the great bulk of the species
leaves the Northern States in winter, a few individuals remain in
sheltered swamps, where wild berries furnish abundant food. The robin
is an omnivorous feeder and its food habits have sometimes caused
apprehension to the fruit grower, for it is fond of cherries and other
small fruits, particularly the earlier varieties. For this reason many
complaints have been lodged against the bird, and some persons have
even gone so far as to condemn it. It is, however, far too valuable to
be exterminated, and choice fruit can be readily protected from its
depredations.
[5] _Planesticus migratorius._
[6] _Planesticus migratorius propinquus._
[7] _Planesticus migratorius achrusterus._
Examinations of 1,236 stomachs show that 42 per cent of its food is
animal matter, principally insects, while the remainder is made up
largely of small fruits or berries. Over 16 per cent consists of
beetles, about one-third of which are useful ground beetles, taken
mostly in spring and fall when other insects are scarce. Grasshoppers
make up about 5 per cent of the whole food, but in August they comprise
17 per cent. Caterpillars form about 9 per cent, while the rest of
the animal food, about 11 per cent, is made up of various insects,
with a few spiders, snails, and angleworms. All the grasshoppers,
caterpillars, and bugs, with a large portion of the beetles, are
injurious, and it is safe to say that noxious insects comprise more
than one-third of the robin’s food.
Vegetable food forms 58 per cent of the stomach contents, over 42 per
cent being wild fruits and only a little more than 8 per cent being
possibly cultivated varieties. Cultivated fruit amounting to about
25 per cent was found in the stomachs in June and July, but only a
trifle in August. Wild fruit, on the contrary, is eaten every month and
constitutes a staple food during half the year. No less than 65 species
of fruit were identified in the stomachs; of these, the most important
were 4 species of dogwood, 3 of wild cherries, 3 of wild grapes, 4 of
greenbrier, 2 of holly, 2 of elder; and cranberries, huckleberries,
blueberries, barberries, service berries, hackberries, and persimmons;
together with 4 species of sumac and various other seeds not strictly
fruit.
The depredations of the robin seem to be confined to the smaller and
earlier fruits, few, if any, complaints being made that it eats apples,
peaches, pears, grapes, or even late cherries. By the time these are
ripe the forests and hedges are teeming with wild fruits which the bird
evidently finds more to its taste. The cherry, unfortunately for man,
ripens so early that it is almost the only fruit accessible at a time
when the bird’s appetite has been sharpened by a long-continued diet
of insects, earthworms, and dried berries, and it is no wonder that at
first the rich juicy morsels are greedily eaten.
While the robin takes some cultivated fruits, it must be remembered
that, being a natural enemy of the insect world, it has been working
during the whole season to make that crop a possibility, and when the
fruit ripens the robin already has a standing account with the farmer
for services rendered, with the credits up to this time entirely on his
side.
Since the robin takes ten times as much wild as cultivated fruit,
it seems unwise to destroy the birds to save so little. Nor is this
necessary, for with care both birds and fruit may be preserved. Where
much fruit is grown it is no great loss to give up one tree to the
birds, and in some cases the crop can be protected by scarecrows.
Where wild fruit is not abundant, a few fruit-bearing shrubs and vines
judiciously planted will serve for ornament and provide food for the
birds. The Russian mulberry is a vigorous grower and a profuse bearer,
ripening at the same time as the cherry. So far as observation has
gone, most birds seem to prefer its fruit to any other. It is believed
that a number of mulberry trees planted around the garden or orchard
would fully protect the more valuable fruits.
Much has been written about the delicate discrimination of birds for
choice fruit and their selection of only the finest and costliest
varieties. This is contrary to observed facts. Birds, unlike human
beings, seem to prefer fruit that, like the mulberry, is sweetly
insipid, or that, like the chokecherry or holly, has some astringent
or bitter quality. The so-called black alder, a species of holly, has
bright scarlet berries tasting as bitter as quinine, that ripen late in
October and remain on the bushes through November. Though frost grapes,
the fruit of the Virginia creeper, and several species of dogwood are
abundant at the same time, the birds have been found to eat the berries
of the holly to a considerable extent. It is, moreover, a remarkable
fact that the wild fruits upon which birds largely feed are those which
man neither gathers for his own use nor adopts for cultivation.
THE TITMICE.
Birds of the titmouse family, though insignificant in size, are far
from being so in the matter of food habits. What they lack in size of
body they more than make up in numbers of individuals. While in the
case of some larger birds, as, for instance, the flicker, there is
one pair of eyes to look for food for one large stomach, we have in
the case of the ten times as numerous titmice an equivalent stomach
capacity divided into 10 parts, each furnished with a pair of eyes and
other accessories, as wings and feet. As against the one place occupied
by the larger bird, 10 are being searched for food at the same time by
the smaller species.
The character of the food of titmice gives a peculiar value to their
services, for it consists largely of the small insects and their eggs
that wholly escape the search of larger birds. Throughout the year most
of the species of this group remain on their range, so that they are
constantly engaged in their beneficial work, continuing it in winter
when the majority of their co-workers have sought a milder clime. It is
at this season that the titmice do their greatest good, for when flying
and crawling insects are no more to be found, the birds must feed upon
such species as they find hibernating in crevices, or upon the eggs of
insects laid in similar places. In winter’s dearth of moving insects
the search for such animal food as may be found is perforce thorough
and unremitting.
Within the boundaries of the United States are some 17 species of
titmice, with nearly as many races or subspecies, so that there is
no portion of the country lacking one or more forms. The western
coast region is peculiarly rich in representatives of the family. In
the eastern portion of the country the best-known and most widely
distributed species is the common black-capped chickadee[8] (fig. 3).
This bird, or some of its subspecies, occupies the whole of that part
of the United States north of the latitude of Washington and extends
into Canada. It is a prolific breeder, usually rearing from six to
eight young in a brood.
[8] _Penthestes atricapillus._
[Illustration: Fig. 3.—Black-capped chickadee. Length, about 5¼ inches]
Examination of 289 stomachs of this chickadee shows that its food
consists of 68 per cent animal matter (insects) and 32 per cent
vegetable matter. The former is made up of small caterpillars and
moths and their eggs. Prominent among the latter are the eggs of the
tent-caterpillar moths, both the orchard and forest species. As these
are two of our most destructive insects, the good done by the chickadee
in devouring their eggs needs no comment. During the winter the
chickadee’s food is made up of larvæ, chrysalids, and eggs of moths,
varied by a few seeds, but as spring brings out hordes of flying,
crawling, and jumping insects, the bird varies its diet by taking also
some of these. Flies and bugs are the favorites until the weather
becomes quite warm, when beetles and small wasps also are enjoyed.
Among the bugs may be mentioned the plant lice and their eggs which are
eaten in winter. The beetles nearly all belong to the group of snout
beetles, more commonly known as weevils. These insects are mostly of
small size, and nearly all are known to the farmer or fruit raiser as
pests. Seventeen of them were found in one stomach. The plum curculio
and the cotton-boll weevil may be taken as fair examples. Grasshoppers
do not at any time constitute an important element of the food of the
chickadee, as they are too large for so small a bird; moreover they are
for the most part terrestrial insects, while the bird is essentially
arboreal. Small wasps and ants are eaten to some extent. Spiders
constitute an important element of the food and are eaten at all times
of the year, the birds locating them when they are hibernating in
winter, as well as when they are active in summer. The vegetable food
of the chickadee consists largely of small seeds except in summer when
they are replaced by pulp of wild fruit. The wax from the seeds of
poison ivy is eaten during the winter months, but the seeds themselves
are not taken. In this respect the chickadee differs from most other
birds which swallow the seeds whole; these, after digesting the wax,
pass the seeds through the alimentary canal, and so scatter them
broadcast to reproduce the noxious plants.
In the southern part of the country the Carolina chickadee[9] and the
tufted tit[10] replace the black-cap, but their food habits are so
similar that there is practically no difference in the work done. In
the West several other species occur; one of the most interesting is
the bush tit[11] which, with several subspecies, occupies the whole
Pacific coast region. They are active, social little creatures, and
except for a short time during the breeding season are found in flocks,
flitting from tree to tree, busily hunting for insects and their eggs
The contents of 66 stomachs of these birds were found to consist
mostly of injurious insects to the extent of 83 per cent. Of these the
most important was a small hemipterous insect which amounted to more
than half of the stomach contents. These insects are of considerable
economic importance, as they frequently infest grapevines and other
plants to a harmful extent. Several stomachs were almost exclusively
filled with these minute creatures, some containing as many as 100
individuals.
[9] _Penthestes carolinensis._
[10] _Bæolophus bicolor._
[11] _Psaltriparus minimus._
Perhaps the most important and interesting insect found was the black
olive scale, which occurred in 24 stomachs and amounted to a little
more than 18 per cent of the food. In addition a number of the stomachs
were more or less filled with another scale, which was not further
identified. A number of small snout beetles (weevils) were eaten and
some small caterpillars; there were also the remains of a spider.
The vegetable food of the species seemed to consist mostly of seeds,
but they were so broken up as to defy recognition. A little fruit pulp
and a little mast were also found.
Among the stomachs of the bush tits examined were those of one brood
of eight nestlings about 10 days old. The vegetable matter in these
stomachs was only three-fourths of 1 per cent and consisted of one seed
and some rubbish. The animal matter was made up of beetles, wasps,
bugs, caterpillars and pupæ, and spiders. The greatest interest lies in
the fact that every one of these stomachs contained pupæ of the codling
moth, on an average of over five to each. The oak tree in which these
birds were found was in a belt of timber near a neglected orchard which
the parent birds used as a foraging ground, and they did their best to
remedy the neglect of the owner. As feeding and digestion in the case
of nestling birds is almost continuous during the hours of daylight,
the above record would be several times repeated during a day’s
feeding. There were probably not less than a dozen nests of the bush
tit along the border of this orchard, and these birds must have exerted
a great restrictive influence upon the increase of the codling moth, as
well as of other insects in that vicinity.
THE WRENS.
[Illustration: Fig. 4.—House wren. Length, about 4¾ inches.]
The diminutive house wren[12] (fig. 4) frequents barns and gardens, and
particularly old orchards in which the trees are partially decayed. He
makes his nest in a hollow where perhaps a woodpecker had a domicile
the year before, but he is a pugnacious character, and if he happens to
fancy one of the boxes put up for bluebirds, he does not hesitate to
take it. He is usually not slow to avail himself of boxes, gourds, tin
cans, or empty jars placed for his accommodation.
[12] _Troglodytes aëdon._
In food habits the house wren is entirely beneficial. He may be said
to live upon animal food alone, for an examination of 88 stomachs
showed that 98 per cent of the contents was made up of insects or their
allies, and only 2 per cent was vegetable food, including bits of grass
and similar matter, evidently taken by accident with the insects. Half
of this food consisted of grasshoppers and beetles; the remainder of
caterpillars, bugs, and spiders. As the wren is a prolific breeder,
frequently rearing in a season from 12 to 16 young, a family of these
birds must cause considerable reduction in the number of insects in a
garden. Wrens are industrious foragers, searching every tree, shrub,
and vine for caterpillars, and examining every post and rail of the
fence and every cranny in the wall for insects or spiders.
The house wren is only one of a numerous group of small birds of
similar habits. There are within the limits of the United States 28
species and subspecies of wrens, occupying more or less completely the
whole country from the Atlantic to the Pacific. With the exception
of the marsh wrens,[13] they all appear to prefer some cosy nook for
a nesting site, and, as it happens, the farm buildings afford just
the place desired. This has led several of the wrens to seek out
the habitations of man, and he is benefited by their destruction of
noxious insects. No species of wren has been accused of harm, and their
presence should be encouraged about every farm, ranch, village, or
suburban residence.
[13] _Telmatodytes palustris._
BROWN THRASHER.
[Illustration: Fig. 5.—Brown thrasher. Length, about 11 inches.]
The brown thrasher[14] (fig. 5) breeds throughout the United States
east of the Great Plains, and winters in the South Atlantic and Gulf
States. It occasionally visits the garden or orchard, but nests in
swamps or in groves standing upon low ground. The thrasher’s favorite
time for singing is in early morning, when, perched on the top of a
tall bush or low tree, it gives an exhibition of vocal powers which
would do credit to a mocking bird. Indeed, in the South, where the
latter bird is abundant, the thrasher is known as the sandy mocker.
[14] _Toxostoma rufum._
The food of the brown thrasher consists of both fruit and insects. An
examination of 636 stomachs showed 36 per cent of vegetable and 64 of
animal food, practically all insects, and mostly taken in spring before
fruit was ripe. Half the insects were beetles and the remainder chiefly
grasshoppers, caterpillars, bugs, and spiders. A few predacious beetles
were eaten, but on the whole the work of the species as an insect
destroyer may be considered beneficial.
Eight per cent of its food is made up of fruits like raspberries and
currants which are or may be cultivated, but the raspberries at least
are as likely to belong to wild as to cultivated varieties. Grain, made
up mostly of scattered kernels of oats and corn, is merely a trifle,
amounting to only 3 per cent. Though some of the corn may be taken from
newly planted fields, it is amply paid for by the destruction of May
beetles which are eaten at the same time. The rest of the food consists
of wild fruit or seeds. Taken all in all, the brown thrasher is a
useful bird, and probably does as good work in its secluded retreats
as it would about the garden, for the swamps and groves are no doubt
the breeding grounds of many insects that migrate thence to attack the
crops of the farmer.
CATBIRD.
[Illustration: Fig. 6.—Catbird. Length, about 9 inches.]
The catbird[15] (fig. 6), like the thrasher, is a lover of swamps and
delights to make its home in a tangle of wild grapevines, greenbriers,
and shrubs, where it is safe from attack and can find its favorite
food in abundance. It is found throughout the United States west to
the Rocky Mountains, and extends also from Washington, Idaho, and Utah
northward into the provinces of Canada. It winters in the Southern
States, Cuba, Mexico, and Central America.
[15] _Dumetella carolinensis._
Reports from the Mississippi Valley indicate that the catbird is
sometimes a serious annoyance to fruit growers. The reason for such
reports may possibly be found in the fact that on the prairies
fruit-bearing shrubs, which afford so large a part of this bird’s food,
are conspicuously absent. With the settlement of this region comes an
extensive planting of orchards, vineyards, and small-fruit gardens,
which furnish shelter and nesting sites for the catbird as well as for
other species. There is in consequence a large increase in the numbers
of the birds, but no corresponding gain in the supply of native fruits
upon which they were accustomed to feed. Under these circumstances
what is more natural than for the birds to turn to cultivated fruits
for their food? The remedy is obvious: Cultivated fruits can be
protected by the simple expedient of planting the wild species which
are preferred by the birds. Some experiments with catbirds in captivity
show that the Russian mulberry is preferred to any cultivated fruit.
The stomachs of 645 catbirds were examined and found to contain 44
per cent of animal (insect) and 58 per cent of vegetable food. Ants,
beetles, caterpillars, and grasshoppers constitute three-fourths of
the animal food, the remainder being made up of bugs, miscellaneous
insects, and spiders. One-third of the vegetable food consists of
cultivated fruits, or those which may be cultivated, as strawberries,
raspberries, and blackberries; but while we debit the bird with the
whole of this, it is probable—and in the eastern and well-wooded part
of the country almost certain—that a large part is obtained from wild
vines. The rest of the vegetable matter is mostly wild fruit, as
cherries, dogwood, sour gum, elderberries, greenbrier, spiceberries,
black alder, sumac, and poison ivy. Although the catbird sometimes does
considerable harm by destroying small fruit, it can not on the whole be
considered injurious. On the contrary, in most parts of the country it
does far more good than harm.
THE SWALLOWS.
[Illustration: Fig. 7.—Barn swallow. Length, about 7 inches.]
Seven common species of swallows are found within the limits of the
United States, four of which have abandoned to some extent their
primitive nesting habits and have attached themselves to the abodes of
man.
In the eastern part of the country the barn swallow[16] (fig. 7)
now builds exclusively under roofs, having entirely abandoned the
rock caves and cliffs in which it formerly nested. More recently the
cliff swallow[17] has found a better nesting site under the eaves of
buildings than was afforded by the overhanging cliffs of earth or
stone which it once used and to which it still resorts occasionally in
the East and habitually in the unsettled West. The martin[18] and the
white-bellied, or tree, swallow[19] nest either in houses supplied for
the purpose, in abandoned nests of woodpeckers, or in natural crannies
in rocks. The northern violet-green swallow,[20] the rough-winged
swallow,[21] and the bank swallow[22] still live in practically such
places as their ancestors chose.
[16] _Hirundo erythrogastra._
[17] _Petrochelidon lunifrons._
[18] _Progne subis._
[19] _Iridoprocne bicolor._
[20] _Tachycineta thalassina._
[21] _Stelgidopteryx serripennis._
[22] _Riparia riparia._
Field observation convinces an ordinarily attentive person that
the food of swallows must consist of the smaller insects captured
in mid-air or picked from the tops of tall grass or weeds. This
observation is borne out by an examination of stomachs, which shows
that the food is made up of many small species of beetles which are
much on the wing; many species of mosquitoes and their allies, together
with large quantities of flying ants; and a few insects of similar
kinds. Most of these are either injurious or annoying, and the numbers
destroyed by swallows are not only beyond calculation but almost beyond
imagination.
Unlike many other groups of birds, the six species of swallows found in
the Eastern States extend in a practically unchanged form across the
continent, where they are reinforced by the northern, or Pacific-coast,
violet-green swallow.
It is a mistake to tear down from the eaves of a barn the nests of a
colony of cliff swallows, for so far from disfiguring a building they
make a picturesque addition to it, and the presence of swallows should
be encouraged by every device. It is said that cliff and barn swallows
may be induced to build their nests in a particular locality, otherwise
suitable, by providing a quantity of mud to be used by them as mortar.
Barn swallows may also be encouraged by cutting a small hole in the
gable of the barn, while martins and white-bellied swallows will be
grateful for boxes like those for the bluebird, but placed in a higher
situation.
TOWHEE.
[Illustration: Fig. 8.—Towhee. Length, about 8 inches.]
The towhee, chewink, or ground robin[23] (fig. 8), as it is variously
known, inhabits nearly the whole of the United States east of the Great
Plains. It breeds from the Middle States northward and winters in the
southern half of the country. Naturally associated with the catbird and
brown thrasher, it lives in much the same places, though it is more
given to haunting hedgerows along roads and fences. After snow has
disappeared in early spring an investigation of the rustling so often
heard among the leaves near a fence or in a thicket will frequently
disclose a towhee hard at work scratching for his dinner after the
manner of a hen; and in these places and along the sunny border of
woods old leaves will be found overturned where the bird has been
searching for hibernating beetles and larvæ. The good which the towhee
does in this way can hardly be overestimated, since the death of a
single insect at this time, before it has had an opportunity to deposit
its eggs, is equivalent to the destruction of a host later in the year.
The towhee has also been credited with visiting potato fields and
feeding upon the potato beetle. Its vegetable food consists of seeds
and small wild fruits, but no complaint on this score is known to have
been made. So far as observation goes, the bird never touches either
cultivated fruit or grain; in fact, it is too shy and retiring even to
stay about gardens for any length of time.
[23] _Pipilo erythrophthalmus._
THE SPARROWS.[24]
[24] The sparrows here mentioned are all native species. A full account
of the English, or house, sparrow (_Passer domesticus_), including its
introduction, habits, and depredations, was published in Bul. No. 1
of the Division of Ornithology in 1889. For information in regard to
combating the English sparrow, see Farmers’ Bulletin 493, The English
Sparrow as a Pest, by Ned Dearborn, 1912.
Sparrows are not obtrusive birds, either in plumage, song, or action.
There are some 40 species, with nearly as many subspecies, in North
America. Not more than half a dozen forms are generally known in any
one locality. All the species are more or less migratory, but so widely
are they distributed that there is probably no part of the country
where some can not be found throughout the year.
While sparrows are noted seed eaters, they do not by any means confine
themselves to a vegetable diet. During the summer, and especially in
the breeding season, they eat many insects and feed their young largely
upon the same food. Examination of stomachs of three species—the song
sparrow[25] (fig. 9), chipping sparrow,[26] and field sparrow[27]
(fig. 10)—shows that about one-third of the food consists of insects,
comprising many injurious beetles, as snout beetles or weevils, and
leaf beetles. Many grasshoppers are eaten. In the case of the chipping
sparrow these insects form one-eighth of the food. Grasshoppers would
seem to be rather large morsels, but the bird probably confines
itself to the smaller species; indeed, the greatest amount (over 36
per cent) is eaten in June, when the larger species are still young
and the smaller most numerous. Besides the insects already mentioned,
many wasps and bugs are taken. Predacious and parasitic hymenopterous
insects and predacious beetles, all useful, are eaten only to a slight
extent, so that as a whole the insect diet of the native sparrows may
be considered beneficial. There are several records of potato-bug larvæ
eaten by chipping sparrow’s.
[25] _Melospiza melodia._
[26] _Spizella passerina._
[27] _Spizella pusilla._
[Illustration: Fig. 9.—Song sparrow. Length, about 6½ inches.]
Their vegetable food is limited almost exclusively to hard seeds.
This might seem to indicate that the birds feed to some extent upon
grain, but the stomachs examined show only one kind, oats, and but
little of that. The great bulk of the food is made up of grass and weed
seed, which form almost the entire diet during winter, and the amount
consumed is immense.
In the agricultural region of the upper Mississippi Valley, by
roadsides, on borders of cultivated fields, or in abandoned fields,
wherever they can obtain a foothold, masses of rank weeds spring up and
often form almost impenetrable thickets which afford food and shelter
for immense numbers of birds and enable them to withstand great cold
and the most terrible blizzards. A person visiting one of these weed
patches on a sunny morning in January, when the thermometer is 20° or
more below zero, will be struck with the life and animation of the busy
little inhabitants. Instead of sitting forlorn and half frozen, they
may be seen flitting from branch to branch, twittering and fluttering,
and showing every evidence of enjoyment and perfect comfort. If one of
them is captured it will be found in excellent condition; in fact, a
veritable ball of fat.
[Illustration: Fig. 10.—Field sparrow. Length, about 5½ inches.]
The snowbird[28] and tree sparrow[29] are perhaps the most numerous of
all the sparrows. Examination of many stomachs shows that in winter the
tree sparrow feeds entirely upon seeds of weeds. Probably each bird
consumes about one-fourth of an ounce a day. In an article contributed
in 1881 to the New York Tribune the writer estimated the amount of
weed seed annually destroyed by these birds in Iowa. On the basis of
one-fourth of an ounce of seed eaten daily by each bird, and an average
of ten birds to each square mile, remaining in their winter range
200 days, there would be a total of 1,750,000 pounds, or 875 tons of
weed seed consumed in a single season by this one species. Large as
are these figures, they unquestionably fall far short of the reality.
The estimate of 10 birds to a square mile is very conservative, for
in Massachusetts, where the food supply is less than in the Western
States, the tree sparrow is even more abundant than this in winter.
The writer has known places in Iowa where several thousand tree
sparrows could be seen within the space of a few acres. This estimate,
moreover, is for a single species, while, as a matter of fact, there
are at least half a dozen birds (not all sparrows) that habitually
feed during winter on these seeds. Farther south the tree sparrow is
replaced in winter by the white-throated sparrow,[30] the white-crowned
sparrow,[31] the fox sparrow,[32] the song sparrow, the field sparrow,
and several others; so that all over the land a vast number of these
seed eaters are at work during the colder months reducing next year’s
crop of worse than useless plants.
[28] _Junco hyemails._
[29] _Spizella monticola._
[30] _Zonotrichia albicollis._
[31] _Zonotrichia leucophrys._
[32] _Passerella iliaca._
HOUSE FINCH.
Of all the sparrow group, there is probably no member, unless it be
the exotic form known as the English sparrow,[33] that has by reason
of its food habits called down so many maledictions upon its head as
the house finch,[34] red-head, or linnet, as it is variously called.
This bird, like the other members of its family, is by nature a seed
eater, and before the beginning of fruit raising in California probably
subsisted upon the seeds of weeds, with an occasional taste of some
wild berry. Now, however, when orchards have extended throughout the
length and breadth of the State and every month from May to December
sees some ripening fruit, the linnets take their share. As their name
is legion, the sum total of the fruit that they destroy is more than
the fruit raiser can well spare. As the bird has a stout beak, it has
no difficulty in breaking the skin of the hardest fruit and feasting
upon the pulp, thereby spoiling the fruit and giving weaker-billed
birds a chance to sample and acquire a taste for what they might not
otherwise have molested. Complaints against this bird have been many
and loud, more especially in the years when fruit crops first came to
be an important factor in the prosperity of the Pacific coast. At that
time the various fruits afforded the linnets a new and easily obtained
food, while cultivation had reduced their formerly abundant supply
of weed seed. When the early fruit growers saw their expected golden
harvest suddenly snatched away or at least much reduced in value by the
little marauders, it is no wonder that they were exasperated and wished
to destroy the authors of the mischief.
[33] _Passer domesticus._
[34] _Carpodacus mexicanus frontalis._
In order to test the matter thoroughly and ascertain whether these
birds ate any other kind of food that might to some extent offset the
damage inflicted upon the fruit, the horticulturists and ornithologists
of California were requested to secure a number of the stomachs of
these birds and send them to the Biological Survey. An agent was also
sent to the fruit-raising sections, who watched the birds in the
orchards and collected a number of them. In this way 1,206 stomachs
were obtained and carefully examined, and the result shows that animal
food (insects) constituted 2.44 per cent and vegetable food 97.56 per
cent of the stomach contents, not counting gravel.
So small a proportion of animal food can not, of course, mean a great
destruction of insects. As these stomachs were collected in every
month, with the greater number taken during the summer, it is evident
that whatever good one may expect from the linnet must not be looked
for in this direction. Unlike most of the sparrow family, the linnet
does not feed its young upon insects to any great extent. The contents
of the stomachs of a number of nestlings were carefully examined, and
the only animal food was found to consist of woolly plant lice. These
also constituted the great bulk of the animal food eaten by adults.
The vegetable food of the species consists of three principal
items—grain, fruit, and weed seeds. Grain amounts to less than 1½ per
cent in August, which is the month of greatest consumption, and the
average for the year is a trifle more than one-fourth of 1 per cent.
Fruit attains its maximum in September, when it amounts to 27 per cent
of the whole food, but the average for the year is only 10 per cent.
The seeds of weeds constitute the bulk of the diet of the linnet, and
in August, the month of least consumption, amount to about 64 per cent
of the food. The average for the year is 86 per cent.
From the foregoing it is evident that whatever the linnet’s sins may
be, grain eating is not one of them. In view of the great complaint
made against its fruit-eating habit, the small quantity found in the
stomachs taken is somewhat of a surprise. But it must be remembered
that the stomach contents do not tell the whole story. When a bird
takes a single peck from a cherry or an apricot, it spoils the whole
fruit, and in this way may ruin half a dozen in taking a single meal.
It is safe to say that the fruit pulp found in the stomach does not
represent more than one-fifth of what is actually destroyed. That the
linnets are persistent and voracious eaters of early fruits, especially
cherries and apricots, every fruit raiser in California will bear
testimony. That the damage is often serious no one will deny. It is
noticeable, however, that the earliest varieties are the ones most
affected; also, that in large orchards the damage is not perceptible,
while in small plantations the whole crop is frequently destroyed.
THE GRACKLES.
The crow blackbird or grackle[35] (fig. 11) in one or more of its
subspecies is a familiar object in all the States east of the Rocky
Mountains. Throughout the year it is resident as far north as
southern Illinois, and in summer extends its range into the Canadian
Provinces. In the Mississippi Valley it is one of the most abundant
of birds, preferring to nest in the artificial groves and windbreaks
near farms instead of in the natural “timber” which it formerly used.
It breeds also in parks and near buildings, often in considerable
colonies. Farther east, in New England, it is only locally abundant,
though frequently seen in migration. In the latter days of August and
throughout September it is found in immense numbers before moving
southward.
[35] _Quiscalus quiscula._
The grackle is accused of many sins, such as stealing grain and fruit
and robbing the nests of other birds. An examination of 2,346 stomachs
shows that nearly one-third of its food consists of insects, most of
which are injurious. The bird also eats a few snails, crawfishes,
salamanders, small fish, and occasionally a mouse. The stomach contents
do not indicate that it robs other birds’ nests to any great extent, as
remains of birds and birds’ eggs amount to less than half of 1 per cent.
It is on account of its vegetable food that the grackle most deserves
condemnation. Grain is eaten during the whole year, and only for a
short time in summer is other food attractive enough to induce the
bird to alter its diet. The grain taken in winter and spring probably
consists of waste kernels from the stubble. The stomachs do not
indicate that the bird pulls sprouting grain; but the wheat eaten in
July and August and the corn eaten in fall are probably from fields
of standing grain. The total amount of grain consumed during the year
constitutes 45 per cent of the food, but it is safe to say that at
least half is waste grain and consequently of no value. Although the
crow blackbird eats a few cherries and blackberries in their season,
and in the fall some wild fruit, it apparently does no damage in this
way.
[Illustration: Fig. 11.—Purple grackle. Length, about 12 inches.]
Large flocks of grackles no doubt do considerable injury to grain
crops, and there seems to be no remedy, except the destruction of
the birds, which is in itself expensive. During the breeding season,
however, the species does much good by eating insects and by feeding
them to its young, which are reared almost entirely upon this food.
The bird does the greatest amount of good in spring, when it follows
the plow in search of large grubworms, of which it is so fond that it
sometimes literally crams its stomach full of them.
BREWER BLACKBIRD.
The Brewer blackbird[36] takes the place in the Western States of the
grackle, or crow blackbird, which lives in the Mississippi Valley and
farther east and is very similar in appearance and habits. It breeds
east to the Great Plains and north into Canada, and winters over most
of its breeding range in the United States and south to Guatemala. At
home in fields, meadows, and orchards, and about ranch buildings and
cultivated lands generally, it nests in bushes and weeds, sometimes in
trees, and is very gregarious, especially about barnyards and corrals.
The bird feeds freely in stockyards and in cultivated fields, and when
fruit is ripe does not hesitate to take a share. During the cherry
season in California the birds are much in the orchards. In one case
they were observed feeding on cherries, but when a neighboring fruit
grower began to plow his orchard almost every blackbird in the vicinity
was upon the newly opened ground close after the plowman’s heels in its
eagerness to secure the insects turned up.
[36] _Euphagus cyanocephalus._
The laboratory investigation of this bird’s food covered 312 stomachs,
collected in every month and representing especially the fruit and
grain sections of southern California. The animal portion of the food
was 32 per cent and the vegetable 68 per cent.
Caterpillars and their pupæ amounted to 12 per cent of the whole food
and were eaten every month. They include many of those pests known as
cutworms. The cotton-boll worm, or corn-ear worm, was identified in at
least 10 stomachs, and in 11 were found pupæ of the codling moth. The
animal food also included other insects, and spiders, sow bugs, snails,
and eggshells.
The vegetable food may be divided into fruit, grain, and weed seeds.
Fruit was eaten in May, June, and July, not a trace appearing in any
other month, and was composed of cherries, or what was thought to be
such, strawberries, blackberries or raspberries, and fruit pulp or
skins not further identified. However, the amount, a little more than
4 per cent for the year, was too small to make a bad showing, and if
the bird does no greater harm than is involved in its fruit eating it
is well worth protecting. Grain amounts to 54 per cent of the yearly
food and forms a considerable percentage in each month; oats are the
favorite and were the sole contents of 14 stomachs, and wheat of 2,
but no stomach was completely filled with any other grain. Weed seeds,
eaten in every month to the extent of 9 per cent of the food, were
found in rather small quantities and irregularly, and appear to have
been merely a makeshift.
Stomachs of nestlings, varying in age from 24 hours to some that were
nearly fledged, were found to contain 89 per cent animal to 11 per cent
vegetable matter. The largest items in the former were caterpillars,
grasshoppers, and spiders. In the latter the largest items were fruit,
probably cherries; grain, mostly oats; and rubbish.
BALTIMORE ORIOLE.
[Illustration: Fig. 12.—Baltimore oriole. Length, about 7½ inches.]