Transcriber Note
Text emphasis denoted by _Italics_.
Revised!
U. S. DEPARTMENT OF AGRICULTURE.
FARMERS' BULLETIN No. 54·
SOME COMMON BIRDS
IN THEIR RELATION TO AGRICULTURE.
BY
F. E. L. BEAL, B. S.,
ASSISTANT ORNITHOLOGIST, BIOLOGICAL SURVEY.
[May, 1897.]
[Illustration]
WASHINGTON:
GOVERNMENT PRINTING OFFICE.
1898.
CONTENTS.
Page.
Introduction 3
The cuckoos (_Coccyzus americanus and C. erythophthalmus_) (fig. 1) 5
The woodpeckers (figs. 2-5) 6
The kingbird (_Tyrannus tyrannus_) (fig. 6) 11
The phœbe (_Sayornis phœbe_) (fig. 7) 13
The bluejay (_Cyanocitta cristata_) (fig. 8) 14
The crow (_Corvus americanus_) 15
The bobolink, or ricebird (_Dolichconyx oryzivorus_) (fig. 9) 17
The redwinged blackbird (_Agelaius phœniceus_) (fig. 10) 19
The meadow lark, or old field lark (_Sturnella magna_) (fig. 11) 21
The Baltimore oriole (_Icterus galbula_) (fig. 12) 23
The crow blackbird, or grackle (_Quiscalus quiscula_) (fig. 13) 24
The sparrows (fig. 14) 26
The rose-breasted grosbeak (_Zamelodia ludoviciana_) (fig. 15) 28
The swallows (fig. 16) 30
The cedarbird (_Ampelis cedrorum_) (fig. 17) 31
The catbird (_Galeoscoptes carolinensis_) (fig. 18) 33
The brown thrasher (_Harporhynchus rufus_) (fig. 19) 34
The house wren (_Troglodytes aëdon_) (fig. 20) 35
The robin (_Merula migratoria_) (fig. 21) 37
The bluebird (_Sialia sialis_) (fig. 22) 39
SOME COMMON BIRDS IN THEIR RELATION TO AGRICULTURE.
INTRODUCTION.
It has long been known that birds play an important part in relation to
agriculture, but there seems to be a tendency to dwell on the harm they do
rather then on the good. Whether a bird is injurious or beneficial depends
almost entirely upon what it eats, and in the case of species which are
unusually abundant or which depend in part upon the farmer's crops for
subsistence the character of the food often becomes a very practical
question. If crows or blackbirds are seen in numbers about cornfields,
or if woodpeckers are noticed at work in an orchard, it is perhaps not
surprising that they are accused of doing harm. Careful investigation,
however, often shows that they are actually destroying noxious insects,
and also that even those which do harm at one season may compensate
for it by eating noxious species at another. Insects are eaten at all
times by the majority of land birds, and during the breeding season most
kinds subsist largely and rear their young exclusively on this food.
When insects are unusually plentiful, they are eaten by many birds which
ordinarily do not touch them. Even birds of prey resort to this diet, and
when insects are more easily obtained than other fare, the smaller hawks
and owls live on them almost entirely. This was well illustrated during
the recent plague of Rocky Mountain locusts in the Western States, when it
was found that locusts were eaten by nearly every bird in the region, and
that they formed almost the entire food of a large majority of the species.
Within certain limits, birds feed upon the kind of food that is most
accessible. Thus, as a rule, insectivorous birds eat the insects that
are most easily obtained, provided they do not have some peculiarly
disagreeable property. It is not probable that a bird habitually passes by
one kind of insect to look for another which is more appetizing, and there
seems little evidence in support of the theory that tire selection of
food is restricted to any particular species of insect, for it is evident
that a bird eats those which by its own method of seeking are most easily
obtained. Thus, a ground-feeding bird eats those it finds among the dead
leaves and grass; a flycatcher, watching for its prey from some vantage
point, captures entirely different kinds; and the woodpecker and warbler,
in the tree tops, select still others. It is thus apparent that a bird's
diet is likely to be quite varied, and to differ at different seasons of
the year.
In investigating the food habits of birds, field observation can be relied
on only to a limited extent, for it is not always easy to determine what
a bird really eats by watching it. In order to be positive on this point,
it is necessary to examine the stomach contents. When birds are suspected
of doing injury to field crops or fruit trees, a few individuals should be
shot and their stomachs examined. This will show unmistakably whether or
not the birds are guilty.
In response to a general demand for definite information regarding the
food habits of our native birds, the biological Survey of the Department
of Agriculture has for some years past been conducting a systematic
investigation of the food of species which are believed to be of economic
importance. Thousands of birds' stomachs have been carefully examined in
the laboratory, and all the available data respecting the food brought
together. The results of the investigations relating to birds of prey,
based on an examination of nearly 3,000 stomachs, were published in 1893,
in a special bulletin entitled The Hawks and Owls of the United States.
Many other species have been similarly studied and the results published,
either in special bulletins or as articles in the yearbooks. The present
bulletin contains brief abstracts of the results of food studies of about
30 grain and insect eating birds belonging to 10 different families.[1]
[1] The limits of this bulletin preclude giving more than a very brief
statement regarding the food of each bird, but more detailed accounts
of some of the species will be found in the following reports of the
Biological Survey (formerly Division of Ornithology and Mammalogy): The
Cuckoos--Bulletin No. 9, 1898, pp. 1-14; Crow--Bulletin No. 6, 1895,
pp. 1-98; Woodpeckers--Bulletin No. 7, 1895, pp. 1-39; Kingbird--Annual
Report Secretary of Agriculture for 1893, pp. 233-234; Redwinged
Blackbird--Yearbook for 1897, pp. 349-351; Baltimore Oriole--Yearbook
for 1895, pp. 426-430; Grackles--Yearbook for 1894, pp. 233-248;
Meadowlark--Yearbook for 1895, pp. 420-426; Cedarbird--Annual Report
Secretary of Agriculture for 1892, pp. 197-200; Catbird, Brown Thrasher,
and Wren--Yearbook for 1895, pp. 405-418.
These species comprise among others the crow blackbirds and ricebirds,
against which serious complaints have been made on account of the damage
they do to corn, wheat, rice, and other crops; and also the cuckoos,
grosbeaks, and thrashers, which are generally admitted to be beneficial,
but whose true value as insect destroyers has not been fully appreciated.
The practical value of birds in controlling insect pests should be more
generally recognized. It maybe an easy matter to exterminate the birds
in an orchard or grain field, but it is an extremely difficult one to
control the insect pests. It is, certain, too, that the value of our
native sparrows as weed destroyers is not appreciated. Weed seed forms
an important item of the winter food of many of these birds, and it is
impossible to estimate the immense numbers of noxious weeds which are thus
annually destroyed.
If birds are protected and encouraged to nest about the farm and garden,
they will do their share in destroying noxious insects and weeds, and a
few hours spent in putting up boxes for bluebirds, martins, and wrens will
prove a good investment. Birds are protected by law in many States, but
it remains for the agriculturalists to see that the laws are faithfully
observed.
THE CUCKOOS.
(_Coccyzus americanus and C. erythophthalmus_)
Two species of cuckoos, the yellow-billed (fig. 1) and the black-billed,
are common in the United States east of the Plains, and a subspecies of
the yellow-billed extends westward to the Pacific. While the two species
are quite distinct, they do not differ greatly in food habits, and their
economic status is practically the same.
[Illustration: Fig. 1.--Yellow-billed cuckoo.]
An examination of 155 stomachs has shown that these cuckoos are much
given to eating caterpillars, and, unlike most birds, do not reject those
covered with hair. In fact, cuckoos eat so many hairy caterpillars that
the hairs pierce the inner lining of the stomach and remain there, so that
when the stomach is opened and turned inside out, it appears to be lined
with a thin coating of fur.
An examination of the stomachs of 40 black-billed cuckoos, taken during
the summer months, showed the remains of 900 caterpillars, 44 beetles,
96 grasshoppers, 100 sawflies, 30 stink bugs, and 15 spiders. In all
probability more individuals than these were represented, but their
remains were too badly broken for recognition. Most of the caterpillars
were hairy, and many of them belonged to a genus that lives in colonies
and feeds on the leaves of trees, including the apple tree. One stomach
was filled with larvæ of a caterpillar belonging to the same genus as the
tent caterpillar, while others contained that species. Other larvæ were
those of large moths, for which the bird seems to have a special fondness.
The beetles were mainly click beetles and weevils, with a few May beetles.
The sawflies were all found in two stomachs, one of which contained no
less than 100 in the larval stage.
Of the yellow-billed cuckoo, 109 stomachs (collected from May to October,
inclusive) were examined. The contents consisted of 1,865 caterpillars, 93
beetles, 242 grasshoppers, 37 sawflies, 69 bugs, 6 flies, and 86 spiders.
Most of the caterpillars belonged to hairy species and many of them were
of large size. One stomach contained 250 American tent caterpillars;
another 217 fall webworms. In places where tent caterpillars are abundant
they seem to constitute a large portion of the food of these two birds.
The beetles were distributed among several families, but all more or less
harmful to agriculture. In the same stomach which contained the tent
caterpillars were two Colorado potato beetles; in another were three
goldsmith beetles and remains of several other large beetles. Besides
grasshoppers were several katydids and tree crickets. The sawflies were
in the larval stage, in which they resemble caterpillars so closely that
they are commonly called false caterpillars, and perhaps this likeness may
be the reason the cuckoos eat them so freely. The bugs consisted of stink
bugs and cicadas or dog-day harvest flies, with the single exception of
one wheel bug, which was the only useful insect eaten, unless the spiders
be counted as such.
THE WOODPECKERS.
Five or six species of woodpeckers are familiarly known throughout the
eastern United States, and in the west are replaced by others of similar
habits. Several species remain in the northern States through the entire
year, while others are more or less migratory.
Farmers are prone to look upon woodpeckers with suspicion. When the birds
are seen scrambling over fruit trees and pecking at the bark, and fresh
holes are found in the tree, it is concluded that they are doing harm.
Careful observers, however, have noticed that, excepting a single species,
these birds rarely leave any important mark on a healthy tree, but that
when a tree is affected by wood-boring larvæ the Insects are accurately
located, dislodged, and devoured. In case the holes from which the borers
are taken are afterwards occupied by colonies of ants, these ants in turn
are drawn out and eaten.
Two of the best known woodpeckers, the hairy woodpecker (_Dryobates
villosus_) (fig. 2) and the downy woodpecker (_D. pubescens_), including
their races, range over the greater part of the United States, and for the
most part remain throughout the year in their usual haunts. They differ
chiefly in size, for their colors are practically the same, and the males,
like other woodpeckers, are distinguished by a scarlet patch on the head.
[Illustration: Fig. 2.--Hairy woodpecker.]
An examination of many stomachs of these two birds shows that from
two-thirds to three-fourths of the food consists of insects, chiefly
noxious. Wood-boring beetles, both adults and larvæ, are conspicuous, and
with them are associated many caterpillars, mostly species that burrow
into trees. Next in importance are the ants that live in decaying wood,
all of which are sought by woodpeckers and eaten in great quantities. Many
ants are particularly harmful to limber, for if they find a small spot of
decay in the vacant burrow of some wood-borer, they enlarge the hole, and
as their colony is always on the increase, continue to eat away the wood
until the whole trunk is honey-combed. Moreover, these insects are not
accessible to other birds, and could pursue their career of destruction
unmolested were it not that the woodpeckers, with beaks and tongues
especially fitted for such work, dig out and devour them. It is thus
evident that woodpeckers are great conservators of forests. To them, more
than to any other agency, we owe the preservation of timber from hordes of
destructive insects.
One of the larger woodpeckers familiar to everyone is the flicker, or
golden-winged woodpecker (_Colaptes auratus_) (fig. 3), which is generally
distributed throughout the United States from the Atlantic Coast to the
Rocky Mountain. It is there replaced by the red-shafted flicker (_C.
cafer_), which extends westward to the Pacific. The two species are as
nearly identical in food habits as their environment will allow. The
flickers, while genuine woodpeckers, differ somewhat in habits from the
rest of the family, and are frequently seen upon the ground searching
for food. Like the downy and hairy woodpeckers, they eat wood-boring
grubs and ants, but the number of ants eaten is much greater. Two of the
flickers' stomachs examined were completely filled with ants, each stomach
containing more than 3,000 individuals. These ants belonged to species
which live in the ground, and it is these insects for which the flicker is
searching when running about in the grass, although some grasshoppers are
also taken.
[Illustration: Fig. 3.--Flicker.]
The red-headed woodpecker (_Melanerpes erythrocephalus_) (fig. 4) is well
known east of the Rocky Mountains, but is rather rare in New England.
Unlike some of the other species, it prefers fence posts and telegraph
poles to trees as a foraging ground. Its food therefore naturally differs
from that of the preceding species, and consists largely of adult beetles
and wasps, which it frequently captures on the wing, after the fashion
of flycatchers. Grasshoppers also form an important part of the food.
The red-head has a peculiar habit of selecting very large beetles, as
shown by the presence of fragments of several of the largest species in
the stomachs. Among the beetles were quite a number of predaceous ground
beetles, and unfortunately some tiger beetles, which are useful insects.
The red-head has been accused of robbing the nests of other birds; also
of attacking young birds and poultry and peeking out their brains, but
as the stomachs showed little evidence to substantiate this charge it is
probable that the habit is rather exceptional.
[Illustration: Fig. 4.--Red-headed woodpecker.]
It has been customary to speak of the smaller woodpeckers as "sapsuckers,"
under the belief that they drill holes in the bark of trees for the
purpose of drinking the sap and eating the inner bark. Close observation,
however, has fixed this habit upon only one species, the yellow-bellied
woodpecker, or sapsucker (_Sphyrapicus varius_) (fig. 5). This bird has
been shown to be guilty of pecking holes in the bark of various forest
trees, and sometimes in that of apple trees, from which it drinks the sap
when the pits become filled. It has been proved, however, that besides
taking the gap the bird captures large numbers of insects which are
attracted by the sweet fluid, and that these form a very considerable
portion of its diet. In some cases the trees are injured by being thus
punctured, and die in a year or two, but since comparatively few are
touched the damage is not great. It is equally probable, moreover, that
the bird fully compensates for this injury by the insects it consumes.
The vegetable food of woodpeckers is varied, but consists largely of small
fruits and berries. The downy and hairy woodpeckers eat such fruits as
dogwood, Virginia creeper, and others, with the seeds of poison ivy,
sumac, and a few other shrubs. The flicker also eats a great many small
fruits and the seeds of a considerable number of shrubs and weeds. None of
the three species is much given to eating cultivated fruits or crops.
The red-head has been accused of eating the larger kinds of fruit, such
as apples, and also of taking considerable corn. The stomach examinations
show that to some extent these charges are substantiated but that the
habit is not prevalent enough to cause much damage. It is quite fond of
mast, especially beechnuts, and when these nuts are plentiful the birds
remain north all winter, instead of migrating as is their usual custom.
[Illustration: Fig. 5.--Yellow-bellied woodpecker.]
Half the food of the sapsucker, aside from sap, consists of vegetable
matter, largely berries of the kinds already mentioned, and also a
quantity of the inner bark of trees, more of which is eaten by this
species than by any other.
Many other woodpeckers are found in America, but their food habits agree
in the main with those just described. Those birds are certainly the only
agents which can successfully cope with certain insect enemies of the
forests, and, to some extent, of fruit trees also. For this reason, if for
no other, they should be protected in every possible way.
THE KINGBIRD
(_Tyrannus tyrannus_)
The kingbird (fig. 6) Is essentially a lover of the orchard, and wherever
the native groves have been replaced by fruit trees this pugnacious bird
takes up its abode. It breeds in all of the States east of the Rocky
Mountains, and less commonly in the Great Basin and on the Pacific Coast.
It migrates south early in the fall, and generally leaves the United
States to spend the winter in more southern latitudes.
[Illustration: Fig. 6.--Kingbird.]
The kingbird manifests its presence in many ways. It is somewhat
boisterous and obtrusive, and its antipathy for hawks and crows is well
known. It never hesitates to give battle to any of these marauders, no
matter, how superior in size, and for this reason a family of kingbirds is
a desirable adjunct to a poultry yard. On one occasion in the knowledge of
the writer a hawk which attacked a brood of young turkeys was pounced upon
and so severely buffeted by a pair of kingbirds, whose nest was near by,
that the would-be robber was glad to escape without his prey. Song birds
that nest near the kingbird are similarly protected.
In its food habits this species is largely insectivorous. It is a true
flycatcher by nature, and takes a large part of its food on the wing. It
does not, however, confine itself to this method of hunting, but picks
up some insects from trees and weeds, and even descends to the ground in
search of myriapods or thousand legs. The chief complaint against the
kingbird is that it preys largely upon honeybees; and this charge has been
made both by professional bee keepers and others. Many observers have seen
the bird at work near hives, and there is no reason to doubt the honesty
of their testimony. One bee raiser in Iowa, suspecting the kingbirds of
feeding upon his bees, shot a number near his hives, but when the birds'
stomachs were examined by an expert entomologist not a trace of honeybees
could be found.
The Biological Survey has made an examination of 281 stomachs collected
in various parts of the country, but found only 14 containing remains of
honeybees. In these 14 stomachs there were in all 50 honeybees, of which
40 were drones, 4 were certainly workers, and the remaining 6 were too
badly broken to be identified as to sex.
The insects that constitute the great bulk of the food of this bird are
noxious species, largely beetles--May beetles, click beetles (the larvæ
of which are known as wire worms), weevils, which prey upon fruit and
grain, and a host of others. Wasps, wild bees, and ants are conspicuous
elements of the food, far outnumbering the hive bees. During summer
many grasshoppers and crickets, as well as leaf hoppers and other bugs,
are also eaten. Among the flies were a number of robber flies--insects
which prey largely upon other insects, especially honeybees, and which
have been known to commit in this way extensive depredations. It is thus
evident that the kingbird by destroying these flies actually does good
work for the apiarist. Nineteen robber flies were found in the stomachs
examined; these may be considered more than an equivalent for the four
worker honeybees already mentioned. A few caterpillars are eaten, mostly
belonging to the group commonly known as cutworms, all the species of
which are harmful. About 10 per cent of the food consists of small native
fruits, comprising some twenty common species of the roadsides and
thickets, such as dogwood berries, elder berries and wild grapes. The
bird has not been reported as eating cultivated fruit to an injurious
extent, and it is very doubtful if this is ever the case, for cherries
and blackberries are the only ones that might have come from cultivated
places, and they were found in but few stomachs.
Three points seem to be clearly established in regard to the food of the
kingbird--(1) that about 90 per cent consists of insects, mostly injurious
species; (2) that the alleged habit of preying upon honeybees is much less
prevalent than has been supposed, and probably does not result in any
great damage; and (3) that the vegetable food consists almost entirely of
wild fruits which have no economic value. These facts, taken in connection
with its well-known enmity for hawks and crows, entitle the kingbird to a
place among the most desirable birds of the orchard or garden.
THE PHŒBE.
(_Sayornis phœbe._)
Among the early spring arrivals at the North, none more welcome than the
phœbe (fig. 7). Though, naturally building its nest under an overhanging
cliff of rock or earth, or in the mouth of a cave, its preference for the
vicinity of farm buildings is so marked that in the more thickly settled
parts of the country the bird is seldom seen at any great distance from a
farmhouse except where a bridge spans some stream, affording a secure spot
for a nest. Its confiding disposition has rendered it a great favorite,
and consequently it is seldom disturbed. It breeds throughout the United
States east of the Great Plains, and winters from the South Atlantic and
Gulf States southward.
[Illustration: Fig. 7.--Phœbe.]
The phœbe subsists almost exclusively upon insects, most of which are
caught upon the wing. An examination of 80 stomachs showed that over 93
per cent of the year's food consists of insects and spiders, while wild
fruit constitutes the remainder. The insects belong chiefly to noxious,
species, and include many click beetles. May beetles, and weevils.
Grasshoppers in their season are eaten to a considerable extent, while
wasps of various species, many flies of species that annoy cattle, and a
few bugs and spiders are also eaten regularly. It is evident that a pair
of phœbes must materially reduce the number of insects near a garden or
field, as the birds often, if not always, raise two broods a year, and
each brood numbers from four to six young.
The vegetable portion of the food is unimportant, and consists mainly of a
few seeds, with small fruits, such as wild cherries, elder berries, and
juniper berries. The raspberries and blackberries found in the stomachs
were the only fruits that might have banged to cultivated varieties, and
the quantity was trifling.
There is hardly a more useful species than the phœbe about the farm,
and it should receive every encouragement. To furnish nesting boxes is
unnecessary, as it usually prefers a more open situation, like a shed, or
a nook under the eaves, but it should be protected from cats and other
marauders.
THE BLUE JAY.
(_Cyanocitta cristata._)
The blue jay (fig. 8) is a common bird of the United States east of the
Great Plains, and remains throughout the year in most of its range,
although its numbers are somewhat reduced in winter in the Northern
States. During spring and summer the jay is forced to become an
industrious hunter for insects, and is not so conspicuous a feature of
the landscape as when it roams the country at will after the cares of the
nesting season are over.
[Illustration: Fig. 8.--Blue Jay.]
Ornithologists and field observers in general declare that a considerable
portion of its food in spring and early summer consists of the eggs and
young of small birds, and some farmers accuse it of stealing corn to an
injurious extent in the fall. While there may be some truth in these
accusations, they have almost certainly been exaggerated. No doubt many
jays have been observed robbing nests of other birds, but thousands have
been seen that were not so engaged.
In an investigation of the food of the blue jay 292 stomachs were
examined, which showed that animal matter comprised 24 per cent and
vegetable matter 70 per cent of the bird's diet. So much has been said
about the nest robbing habits of the jay that special search was made
for traces of birds or birds' eggs in the stomachs, with the result that
shells of small birds' eggs were found in three and the remains of young
birds in only two stomachs. Such negative evidence is not sufficient to
controvert the great mass of testimony upon this point, but it shows that
the habit is not so prevalent as has been believed. Besides birds and
their eggs, the jay eats mice, fish, salamanders, snails, and crustaceans,
which altogether constitute but little more than 1 per cent of its diet.
The insect food is made up of beetles, grasshoppers, caterpillars, and
a few species of other orders, all noxious, except some 3½ per cent of
predaceous beetles. Thus something more than 19 per cent of the whole food
consists of harmful insects. In August the jay, like many other birds,
turns its attention to grasshoppers, which constitute nearly one-fifth of
its food during that month. At this time, also, most of the other noxious
insects, including caterpillars, are consumed, though beetles are eaten
chiefly in spring.
The vegetable food is quite varied, but the item of most interest is
grain. Corn was found in 70 stomachs, wheat in 8, and oats in 2--all
constituting 19 per cent of the total food. Corn is evidently the favorite
grain, but a closer inspection of the record shows that the greater part
was eaten during the first five months of the year, and that very little
was taken after May, even in harvest time, when it is abundant. This
indicates that most of the corn is gleaned from the fields after harvest,
except what is stolen from cribs or gathered in May at planting time.
The jay's favorite food is mast (i. e., acorns, chestnuts, chinquapins,
etc.), which was found in 158 of the 292 stomachs and amounted to more
than 42 per cent of the whole food. In September corn formed 15 and mast
35 per cent, while in October, November, and December corn dropped to
an almost inappreciable quantity and mast amounted to 64, 82, and 83
per cent, respectively. And yet in these months corn is abundant and
everywhere easily accessible. The other elements of food consist of a few
seeds and wild fruits, among which grapes and blackberries predominate.
The results of the stomach examination show, (1) that the jay eats many
noxious insects; (2) that its habit of robbing the nests of other birds is
much less common, than has been asserted; and (3) that it does little harm
to agriculture, since all but a small amount of the corn eaten is waste
grain.
THE CROW.
(_Corvus americanus._)
There are few birds so well known as the common crow, and unlike most
other species he does not seem to decrease in numbers as the country
becomes more densely populated. The crow is commonly regarded as a
blackleg and a thief. Without the dash and brilliancy of the jay, or the
bold savagery of the hawk, he is accused of doing more mischief than
either. That he does pull up sprouting corn, destroy chickens, and rob the
nests of small birds has been repeatedly proved. Nor are these all of his
sins. He is known to eat frogs, toads, salamanders, and some small snakes,
all harmless creatures that do some good by eating insects. With so many
charges against him, it may be well to show why he should not be utterly
condemned.
The examination of a large number of stomachs, while confirming all the
foregoing accusations, has thrown upon the subject a light somewhat
different from that derived slowly from field observation. It shows that
the bird's nesting habit, as in the case of the jay, is not so universal
as has been supposed; and that, so far from being a habitual nest robber,
the crow only occasionally indulges in that reprehensible practice. The
same is true in regard to destroying chickens, for he is able to carry off
none but very young ones, and his opportunities for capturing them are
somewhat limited. Neither are many toads and frogs eaten, and as frogs are
of no great practical value, their destruction is not a serious matter;
but toads are very useful, and their consumption, so far as it goes, must
be counted against crow. Turtles, crayfishes, and snails, of which he eats
quite a large number, may be considered neutral, while mice may be counted
to his credit.
In his insect food, however, the crow makes amends for sins in the rest of
his dietary, although even here the first item is against him. Predaceous
beetles are eaten in some numbers throughout the season, but the number
is not great. May beetles, "dor-bugs," or June bugs, and others of the
same family, constitute the principal food during spring and early summer,
and are fed to the young in immense quantities. Other beetles, nearly all
of a noxious character, are eaten to a considerable extent. Grasshoppers
are first taken in May, but not in large numbers until August, when, as
might be expected, they form the leading article of diet, showing that
the crow is no exception to the general rule that most birds subsist,
to a large extent, upon grasshoppers in the month of August. Many bugs,
some caterpillars, mostly cutworms, and some spiders are also eaten--all
of them either harmful or neutral in their economic relations. Of the
insect diet Mr. E. A. Schwarz says: "The facts, on the whole, speak
overwhelmingly in favor of the crow."
Probably the most important item in the vegetable food is corn, and by
pulling up the newly sprouted seeds the bird renders himself extremely
obnoxious. Observation and experiments with tame crows show that hard, dry
corn is never eaten if anything else is to be had, and if fed to nestlings
it is soon disgorged. The reason crows resort to newly planted fields
is that the kernels of corn are softened by the moisture of the earth,
and probably become more palatable in the process of germination, which
changes the starch of the grain to sugar. The fact, however, remains that
crows eat corn extensively only when it has been softened by germination
or partial decay, or before it is ripe and still "in the milk." Experience
has shown that they may be prevented from pulling up young corn by
tarring the seed, which not only saves corn but forces them to turn their
attention to insects. If they persist in eating green corn it is not so
easy to prevent the damage; but no details of extensive injury in this way
have yet been presented and it is probable that no great harm has been
done.
Crows eat fruit to some extent, but confine themselves for the most part
to wild species, such as dogwood, sour gum, and seeds of the different
kinds of sumac. They have also a habit of sampling almost everything
which appears eatable, especially when food is scarce. For example, they
eat frozen apples found on the trees in winter, or pumpkins, turnips,
and potatoes which have been overlooked or neglected; even mushrooms are
sometimes taken, probably in default of something better.
In estimating the economic status of the crow, it must be acknowledged
that he does some damage, but, on the other hand, he should receive much
credit for the insects which he destroys. In the more thickly settled
parts of the country the crow probably does more good than harm, at
least when ordinary precautions are taken to protect young poultry and
newly-planted corn against his depredations. If, however, corn is planted
with no provision against possible marauders, if hens and turkeys are
allowed to nest and to roam with their broods at a distance from farm
buildings, losses must be expected.
THE BOBOLINK, OR RICEBIRD.
(_Dolichconyx oryzivorus_)
The bobolink (fig. 9) is a common summer resident of the United States,
north of about latitude 40°, and from New England westward to the Great
Plains, wintering beyond our southern border. In New England there are few
birds, if any, around which so much romance has clustered; in the South
none on whose head so many maledictions have been heaped. The bobolink,
entering the United States from the South at a time when the rice fields
are freshly sown, pulls up the young plants and feeds upon the seed. Its
stay, however, is not long, and it soon hastens northward, where it is
welcomed as a herald of summer. During its sojourn in the Northern States
it feeds mainly upon insects and small seeds of useless plants; but while
rearing its young, insects constitute its chief food, and almost the
exclusive diet of its brood. After the young are able to fly, the whole
family gathers into a small flock and begins to live almost entirely upon
vegetable food. This consists for the most part of weed seeds, since in
the North these birds do not appear to molest grain to any great extent.
They eat a few oats, but their stomachs do not reveal a great quantity of
this or any other grain. As the season advances they gather into larger
flocks and move southward, until by the end of August nearly all have
left their breeding grounds. On their way they frequent the reedy marshes
about the mouths of rivers and on the inland waters of the coast region,
subsisting largely upon wild rice. After leaving the Northern States they
are commonly known as reed birds, and having become very fat are treated
as game.
They begin to arrive on the rice fields in the latter part of August, and
during the next month make havoc in the ripening crop. It is unfortunate
that the rice districts lie exactly in the track of their fall migration,
since the abundant supply of food thus offered has undoubtedly served to
attract them more and more, until most of the bobolinks bred in the North
are concentrated with disastrous effect on the south east coast when the
rice ripens in the fall, there was evidently a time when no such supply of
food awaited the birds on their journey southward, and it seems probable
that the introduction of rice culture in the South, combined with the
clearing of the forests in the North, thus affording a larger available
breeding area, has favored an increase in the numbers of this species. The
food habits of the bobolink are not necessarily easily inimical to the
interests of agriculture. It simply happens that the rice affords a supply
of food more easily obtainable than did the wild plants which formerly
occupied the same region. Were the rice fields at a distance from the
line of migration, or north of the bobolinks' breeding ground, they would
probably never be molested; but lying, as they do, directly in the path
of migration, they form a recruiting ground, where the birds can rest and
accumulate flesh and strength for the long sea flight which awaits them in
their course to South America.
[Illustration: Fig. 9.--Bobolink.]
The annual loss to rice growers on account of bobolinks has been estimated
at $2,000,000. In the face of such losses it is evident that no mere
poetical sentiment should stand in the way of applying any remedy which
can be devised. It would be unsafe to assume that the insects which the
birds consume during their residence in the North can compensate for such
destruction. If these figures are any approximation to the truth, the
ordinary farmer will not believe that the bobolink benefits, the Northern
half of the country nearly as much as it damages the Southern half, and
the thoughtful ornithologist will be inclined to agree with him. But even
if the bird really does more harm than good, what is the remedy! For years
the rice planters have been employing men and boys to shoot the birds
and drive them away from the fields, but in spite of the millions slain
every year their numbers do not decrease. In fact, a large part of the
loss sustained is not in the grain which the birds actually eat, but in
the outlay necessary to prevent them from taking it all. At present there
seems to be no effective remedy short of complete extermination of the
species, and this is evidently impracticable even were it desirable.
THE REDWINGED BLACKBIRD.
(_Agelaius phœniceus._)
The redwinged, or swamp, blackbird (fig. 10) is found all over the United
States and the region immediately to the north. While common in most of
its range, its distribution is more or less local, mainly on account of
its partiality for swamps. Its nest is built near standing water, in
tall grass, rushes, or bushes. Owing to this peculiarity the bird may be
absent from large tracts of country which afford no swamps or marshes
suitable for nesting. It usually breeds in large colonies, though single
families, consisting of a male with several wives, may sometimes be found
in a small slough, where each of the females builds, her nest and rears
her own little brood, while her liege lord displays his brilliant colors
and struts in the sunshine. In the Upper Mississippi Valley it finds the
conditions most favorable, for the countless prairie sloughs and the
margins of the numerous shallow lakes form nesting sites for thousands
of redwings; and there are bred the immense flocks which sometimes do so
much damage to the grain fields of the West. After the breeding season is
over, the birds collect in flocks to migrate, and remain thus associated
throughout the winter.
Many complaints have been made against the redwing, and several States
have at times placed a bounty upon its head. It is said to cause great
damage to grain in the West, especially in the Upper Mississippi Valley;
and the rice growers of the South say that it eats rice. No complaints
have been received from the Northeastern portion of the country, where the
bird is much less abundant than in the West and South.
An examination of 725 stomachs showed that vegetable matter forms 74 per
cent of the food, while the animal matter, mainly insects, forms but
26 per cent. A little more than 10 per cent consists of beetles, mostly
harmful species, Weevils, or snout-beetles, amount to 4 per cent of the
year's food, but in June reach 25 per cent. As weevils are among the most
harmful insects known, their destruction should condone for at least some
of the sins of which the bird has been accused. Grasshoppers constitute
nearly 5 per cent of the food, while the rest of the animal matter is
made up of various insects, a few snails, and crustaceans. Several dragon
flies were found, but these were probably picked up dead, for they are
too active to be taken alive, unless by one of the flycatchers. So far as
the insect food as a whole is concerned, the redwing may be considered
entirely beneficial.
[Illustration: Fig. 10.--Redwinged blackbird.]
The interest in the vegetable food of this bird centers around the grain.
Only three kinds, corn, wheat, and oats, were found in appreciable
quantities in the stomachs, and they aggregate but little more than 13
per cent of the whole food, oats forming nearly half of this amount. In
view of the many complaints that the redwing eats grain, this record
is surprisingly small. The crow blackbird has been found to eat more
than three times as much. In the case of the crow, corn forms one-fifth
of the food, so that the redwinged blackbird, whose diet is made up of
only a trifle more than one-eighth of grain, is really one of the least
destructive species; but the most important item of this bird's food is
weed seed, which forms practically the whole food in winter and about 57
per cent of the whole year's fare. The principal weed seeds eaten are
those of ragweed, barn grass, smartweed, and about a dozen others. That
these seeds are preferred is shown by the fact that the birds begin to
eat them in August, when grain is still readily accessible, and continue
feeding on them even after insects become plentiful in April. The redwing
eats very little fruit and does practically no harm in the garden or
orchard.
While it is impossible to dispute the mass of testimony which has
accumulated concerning its grain-eating propensity, the stomach
examinations show that the habit must be local rather than general. As
the area of cultivation increases and the breeding grounds are curtailed,
the species is likely to become reduced in numbers and consequently less
harmful. Nearly seven-eighths of the redwing's food is made up of weed
seed or of insects injurious to agriculture, indicating unmistakably that
the bird should be protected, except, perhaps, in a few places where it is
too abundant.
THE MEADOW LARK, OR OLD FIELD LARK.
(_Sturnella magna._)
The meadow lark (fig. 11) is a common and well-known bird occurring from
the Atlantic Coast to the Great Plains, where it gives way to a closely
related subspecies, which extends thence westward to the Pacific. It
winters from our southern border as far north as the District of Columbia,
southern Illinois, and occasionally Iowa. Although it is a bird of the
plains, finding its most congenial haunts in the prairies of the West, it
does not disdain the meadows and mowing lands of New England. It nests on
the ground and is so terrestrial in its habits that it seldom perches on
trees, preferring a fence rail or a telegraph pole. When undisturbed, it
may be seen walking about with a peculiar dainty step, stopping every few
moments to look about and give its tail a nervous flirt or to sound a note
or two of its clear whistle.
The meadow lark is almost wholly beneficial, although a few complaints
have been made that it pulls sprouting grain, and one farmer claims that
it eats clover seed. As a rule, however, it is looked upon with favor and
is not disturbed.
In the 238 stomachs examined, animal food (practically all insects)
constituted 73 per cent of the contents and vegetable matter 27 per cent.
As would naturally be supposed, the insects were ground species, such as
beetles, bugs, grasshoppers, and caterpillars, with a few flies, wasps,
and spiders. A number of the stomachs were taken from birds that had been
killed when the ground was covered with snow, but still they contained a
large percentage of insects, showing the bird's skill in finding proper
food under adverse circumstances.
Of the various insects eaten, crickets and grasshoppers are the most
important, constituting 29 per cent of the entire year's food and 69 per
cent of the food in August. It is scarcely necessary to enlarge upon this
point, but it can readily be seen what an effect a number of these birds
must have on a field of grass in the height of the grasshopper season.
Of the 238 stomachs collected at all seasons of the year, 178, or more
than two-thirds, contained remains of grasshoppers, and one was filled
with fragments at 37 of those insects. This seems to show conclusively
that grasshoppers are preferred and are eaten whenever they can be
procured. The great number taken in August is especially noticeable. This
is essentially the grasshopper month, i. e., the month when grasshoppers
reach their maximum abundance; and the stomach examination has shown that
a large number of birds resort to this diet in August, no matter what may
be the food during the rest of the year.
[Illustration: Fig. 11.--Meadow lark.]
Next to grasshoppers, beetles make up the most important item of the
meadow lark's food, amounting to nearly 21 per cent, of which about
one-third are predaceous ground beetles. The others are all harmful
species, and when it is considered that the bird feeds exclusively on the
ground, it seems remarkable that so few useful ground beetles are eaten.
Many of them have a disgusting odor, and possibly this may occasionally
save them from destruction by birds, especially when other food is
abundant. Caterpillars, too, form a very constant element, and in May
constitute over 28 per cent of the whole food. May is the month when the
dreaded cutworm begins its deadly career, and then the bird does some of
its best work. Most of these caterpillars are ground feeders, and are
overlooked by birds which habitually frequent trees; but the meadow lark
finds them and devours them by thousands. The remainder of the insect food
is made up of a few ants, wasps, and spiders, with a few bugs, including
some cinch bugs.
The vegetable food consists of grain, weed, and other hard seeds. Grain
in general amounts to 14, and weed and other seeds to 12 per cent. The
grain, principally corn, is mostly eaten in winter and early spring, and
must be therefore simply waste kernels; only a trifle is consumed in
summer and autumn, when it is most plentiful. No trace of sprouting grain
was discovered. Clover seed was found in only six stomachs, and but little
in each. Seeds of weeds, principally ragweed, barn grass, and smartweed,
are eaten from November to April, inclusive, but during the rest of the
year are replaced by insects.
Briefly stated, more than half of the meadow lark's food consists of
harmful insects; its vegetable food is composed either of noxious weeds
or waste grain, and the remainder is made up of useful beetles or neutral
insects and spiders. A strong point in the bird's favor is that, although
naturally an insect eater, it is able to subsist on vegetable food, and
consequently is not forced to migrate in cold weather any farther than is
necessary to find ground free from snow. This explains why it remains for
the most part in the United States during winter, and moves northward as
soon as the snow disappears from its usual haunts.
There is one danger to which the meadow lark is exposed. As its flesh is
highly esteemed the bird is often shot for the table, but it is entitled
to all possible protection, and to slaughter it for game is the least
profitable way to utilize this valuable species.
THE BALTIMORE ORIOLE.
(_Icterus galbula._)
Brilliancy of plumage, sweetness of song, and food habits to which no
exception can be taken are some of the striking characteristics of the
Baltimore oriole (fig. 12). In summer this species is found throughout
the northern half of the United States east of the Great Plains, and
is welcomed and loved in every country home in that broad land. In the
Northern States it arrives rather late, and is usually first seen, or
heard, foraging amidst the early bloom of the apple trees, where it
searches for caterpillars or feeds daintily on the surplus blossoms. Its
nest commands hardly less admiration than the beauty of its plumage or the
excellence of its song. Hanging from the tip of the outermost bough of a
stately elm, it is almost inaccessible, and so strongly fastened as to bid
defiance to the elements.