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Historic, archived document

Do not assume content reflects current
scientific knowledge, policies, or practices.

Issued November 11, 1907.

U.S. DEPARTMENT OF AGRICULTURE
BIOLOGICAL SURVEY—BULLETIN No. 30

C, HART MERRIAM, Chief

BIRDS OF CALIFORNIA

IN RELATION TO THE
FRUIT INDUSTRY

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iy . By F. E. L. BEAL
Assistant, Biological Survey

WASHINGTON
GOVERNMENT PRINTING OFFICE —
1907

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CALIFORNIA BUSI

Issued November 11, 1907.
tes. DEPARTMENT ‘OF AGRICULTURE
BIOLOGICAL SURVEY-—-BULLETIN No. 30

C. HART MERRIAM, Chief

BIRDS OF CALIFORNIA

PN RELATION. TO. THE
PRUE INDUSTRY

PAT I

By F. KE. L. BEAL

Assistant, Biological Survey

WASHINGTON
GOVERNMENT PRINTING OFFICE
1907

—_—S

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LETTER OF TRANSMITTAL.

U.S. DEPARTMENT OF AGRICULTURE,
3IOLOGICAL SURVEY,
Washington, D. C., July 27, 1907.

Sir: I have the honor to transmit herewith as Bulletin No. 30
of the Biological Survey, Part I of a report on the Birds of Cali-
fornia in Relation to the Fruit Industry, by F. E. L. Beal. Fruit
raising in California is a great and growing industry, and the relation
birds bear to it is important. The investigations embodied in the
present report were undertaken with a view to the accurate deter-
mination of the economic status of every species of California bird
that inhabits orchards, in order that it may be possible for the fruit
raiser to discriminate between friends and foes; and for the added
purpose of suggesting remedial measures for the protection of fruit
from destructive species. As expected, the strictly insectivorous
birds prove to be almost wholly beneficial, by far the greater per-
centage of the insects eaten by them being injurious kinds. They are
hence alles of the orchardist and their presence in and near orchards
should be encouraged in every way. Of the species addicted to fruit
eating, not one was found to make its diet wholly, or even chiefly,
of fruit; and the fruit eaters, with possibly the exception of the
house finch, are found to feed upon weed seeds and noxious insects
to such an extent.as to fully offset their destructive propensities.

Respectfully,
C. Hart Merriam,
Chief, Biological Survey.
Hon. James Witson,
Secretary of Agriculture.

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BIRDS OF CALIFORNIA IN RELATION TO THE FRUIT
INDUSTRY—PART I.

INTRODUCTION.

In response to numerous complaints from fruit growers concerning
depredations by birds in orchards and vineyards in the Pacific coast
region, investigation of the subject was undertaken by the Biological
Survey several years ago. In conducting this investigation the
writer spent about nineteen months in California, including the fruit
seasons of 1901, 1903, and 1906, during which time he visited the
most important fruit-growing regions of the State, inspected hun-
dreds of orchards, and interviewed many fruit growers. Kindness
and courtesy were everywhere met with, and every facility was ex-
tended by orchardists for the acquisition of information, even to a
suspension of the customary rules with regard to trespass and shoot-
ing on private grounds. In addition to the knowledge gained by
field observations, stomachs of all the species of Pacific coast birds
economically valuable have been collected, examined, and their con-
tents recorded.

When depredations are so widespread and involve so many differ-
ent species of birds, a thorough knowledge of the nature and extent
of the damage done and of the attending circumstances is of great
importance, Next in importance is a knowledge of the conditions
that obtain in fruit-growing regions where depredations by birds do
not occur. This information should enable the fruit grower to adjust
conditions in his own case so as to mitigate if not wholly prevent
the evil. |

In the following pages much stress is laid on the nature of the
yearly or seasonal food of some of the more important species of
birds, since it often happens that certain birds are more or less harm-
ful to a particular crop of fruit, and vet the year through, all things
considered, do more good than harm. It must not be forgotten in
this connection that there are very few birds whose habits are wholly
beneficial. Most of them are neither wholly beneficial nor wholly
injurious. They are beneficial at some seasons and injurious at
others. In some localities they are deservedly praised for benefits
conferred; in others the same species are condemned for destructive

8 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

habits. With the evidence all in, it is usually possible for the farmer
to properly estimate the status of any given species with reference
to his own farm and his own interests and to adopt measures
accordingly.

It can not be too thoroughly insisted that sound public policy
everywhere forbids the destruction of birds on a large scale for the
purpose of protecting orchard fruits. Wholesale slaughter of birds
in the supposed interest of the orchardist is fortunately rare and
often proceeds from a mistaken idea of their economic relations.
When it is understood that the damage by a certain species is local
and exceptional, that the birds in question are on the whole bene-
ficial and that their destruction will be a loss to the State, the
farmer and the orchardist are usually willing to adopt less drastic
measures in defense of their crops and to spare the birds for the
sake of the general weal.

STATUS OF BIRDS IN NEWLY SETTLED REGIONS.

When a new country is settled, large areas are plowed and brought
under cultivation. In the process great numbers of native shrubs,
weeds, and grasses are destroyed, and various new and exotic plants
and trees are substituted. Coincident with this change in the vege-
table life, and as a necessary consequence of it, great changes in the
conditions and distribution of animal life take place. Some species
are restricted in distribution and greatly reduced in numbers, or even
exterminated, while others become more abundant and more widely
dispersed. The reduction in numbers may occur from actual killing
by man, from the destruction of natural breeding sites through
clearing, and from a diminution of food traceable to the same cause.
The results are exactly the opposite when cultivation and planting
afford a more abundant supply of food, greater facilities for breed-
ing, and better protection from enemies. The natural result of such
conditions is a marked increase in number of the favored species,
and this increase probably explains the great devastation of crops
by birds that occurred on the Atlantic seaboard soon after the first
settlements, and then successively in the States to the westward as
these were gradually settled.

The early days of agriculture in California offer an interesting case
in point. When the native grasses and weeds of the fertile valleys
were destroyed to make room for grain, many species of birds,
notably blackbirds and quails, were suddenly deprived of their natural
subsistence and in place of it were supplied with an abundance of
new and nutritious food. Naturally they preferred the cultivated
erains (wheat, barley, and oats) to the wild oats (Avena fatua) upon
which they had largely depended. Still later, when many of the

INTRODUCTION. 9

grain fields gave way to extensive orchards, which gradually crept
up the hillsides and into the canyons, other species of birds began
to utilize the new kinds of food and also the safe nesting sites
afforded by orchard trees. Species that previously attracted little
attention soon increased in numbers because of the increased food
supply, additional facilities for nesting, and the protection afforded
by man, who killed or drove away their natural enemies. As a result,
some of them suddenly became of great economic importance, owing
to their increased numbers and destructive habits.

MIGRATION OF BIRDS.

Owing to its extent and varied topography, California is rich in
birds, both in species and individuals. Here altitude and topog-
‘caphy, as well as latitude, govern climate. This fact leads to many
peculiarities in distribution and complicates the study of birds in
their economic and other relations. The movements of birds, too, are
more complex than in the eastern part of the United States. The
regular migration north in the spring and south in the fall, which is
the rule over the greater part of the country, is here supplemented, in
the case of many species, by a migration from the mountains, where
they breed, to the valleys, where they winter. Besides the regular
migrations, at times remarkable incursions of a single species take
place. Such was the flight of mountain tanagers (Piranga ludo-
viciana) in the valleys in May, 1896. In several parts of California
these birds appeared in immense numbers in localities where pre-
viously they had been rarely observed. Their appearance coincided
nearly with the ripening of the cherry crop, to which in some places
they did much damage in spite of the fact that great numbers of
them were shot.

CAUSES OF DEPREDATIONS BY BIRDS.

The failure of customary food supply sometimes leads birds to
forage upon crops which they do not commonly eat. This may be
the explanation of the depredations of robins in the fall and winter
of 1900-1901, when thousands of these birds pillaged the olive
orchards in Santa Clara Valley, the region about Santa Barbara, and
other parts of California. In that year it was as much as the olive
growers could do to save part of their crop. Since then no case of
excessive loss of olives has been reported, though occasionally some
damage has been done.

The amount of damage inflicted by birds upon a crop often depends
upon the surroundings. In the case of orchards in the midst of a
treeless plain depredations are mostly confined to such birds as nest
in them, but they may be visited and damaged by others during

10 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

migration. On the other hand, fruit grown near or in brushy can-

yons or on wooded hills is taken by birds that live in such places; or

=)
a stream flowing through a region of orchards may harbor in the
shrubbery on its banks many birds that do not live in the orchard
itself.

Hence depredations by birds may arise: (1) From the settlement
of a region and consequent introduction of new crops, accom-
panied by a diminished supply of natural food; destruction of ene-
mies, and a general change of natural conditions; (2) from failure
of the normal food supply, causing migration in search of food, or
an attack upon some product which the species does not usually eat;
(3) from proximity to a particular crop, in which case the bird natu-
rally eats that which is most available.

CONDITIONS IN CALIFORNIA COMPARED WITH THOSE IN THE EASTERN
STATES.

Before proceeding to a consideration of particular birds, one point
should be specially noted in connection with the subject of the rela-
tion of birds to fruit in California. Those parts of the State where
fruit is grown are not so well supphed with wild fruits on which
birds feed as are the fruit-growing areas of the Eastern States, or
even of those farther north on the Pacific coast. While California
has an abundance of wild berries which serve as food for birds, they
do not commonly grow near orchards and vineyards.

In the Eastern States a plentiful supply of fruit, as acceptable to
birds as the best products of the orchard or garden (perhaps more
acceptable), is usually present in pastures and along roadsides, so
that it is only where wild fruits are exterminated by cultivation that
birds are forced to eat cultivated kinds. So abundant is wild fruit
in some regions, as in the United States east of the Alleghanies, that
it is safe to say that thousands of bushels of blackberries and rasp-
berries which grow wild everywhere annually fall to the ground and
rot, in spite of the fact that great quantities are gathered and eaten
by man as well as by birds. The same is true of blueberries (Vac-
cinium) and huckleberries (Gaylussacia), which are so abundant in
a wild state that in their season they appear in the markets of most
of the cities and large towns, and are eaten in every country home in
the region where they grow. In addition to these are several species
of dogwood (Cornus), holly (Ilex), cherry (Prunus), Viburnum,
and many others, all of which are freely eaten by birds.

Although many of these fruit-bearing shrubs are represented in
California by related species, they usually grow in the mountains
remote from fruit-growing districts. In fact, the elderberry (Sam-
bucus), the introduced pepperberry (Schinus molle), and an ocea-
sional mistletoe berry are the only important uncultivated fruits

INTRODUCTION. RI

that appear in the stomachs of California orchard birds. On the
other hand, in the Eastern States more than 40 species of wild
fruits have been found in the stomachs of a single species—the
Eastern robin. In the general dearth of wild fruits on the horti-
cultural areas of the Pacific coast it is not surprising that when
domestic fruits were first cultivated there the birds gave them a
warm welcome, and the orchardist’s crops suffered accordingly.
Another reason why birds attack fruit in California more than in
the regions farther east is the dryness of the summers, juicy fruits

proving an acceptable substitute for water. To secure enough water
for their necessities California birds must often fly several miles, while
in the Eastern States localities are few in which water can not be
cbtained within a few rods. In confirmation of the theory that in
attacking fruit liquid for slaking thirst is sought by birds as much as
food, it may be stated that much of the injury done to small juicy
fruits in California, such as grapes and cherries, consists of simple ~
punctures in the skin, through which apparently nothing but juice
bas been drawn.

PROTECTIVE MEASURES.

It would appear most desirable that some of the available fruit-
bearing trees, the fruits of which are of little or no value to man, but
which to birds are even more acceptable than cultivated kinds, should
be freely introduced into California for the protection of the orchard-
ist. That some of them would thrive there hardly admits of doubt.
Morus alba, the Russian mulberry, is one of the best, the fruit having
little value unless as food for birds. All fruit-eating species are fond
of it. Both the red and the black mulberries are equally sought after,
but are not often planted for birds alone. The paper mulberry
(Broussonetia papyrifera) is hardy and is a favorite bird food. Sev-
eral species of Prunus or cherry, including the choke cherry (P. v77r-
giniana), and especially its western form (P. demissa), the black
cherry (P.serotina) ,and the bird cherry (P. pennslyvanica) are of great
value in protecting fruit crops, birds almost invariably selecting their
fruit in preference to the cultivated varieties. There are also several
ornamental varieties of cherries, such as the European birdcherry (P.
avium), P. pendula of Japan, and P. spherocarpa of Brazil, which
are hardy, the latter in warm regions only, and valuable as bird foods.
Both the pepper tree, Schinus molle, and the elder, Sambucus, now
abundant in California, are eaten by many birds, and both may be
planted near orchards with the certainty that they will serve to pro-
tect them.

Another measure recommended for the protection of orchard fruit
is a supply of water accessible to the birds. Drinking places for
birds in every large orchard would tend to reduce the injury done to

12 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

fruit, and would serve the added purpose of attracting insectivorous
birds to the locality. Birds undoubtedly select breeding places with.
reference to the convenience of food and water, and a constant supply
of the latter attracts to the vicinity many desirable species. The
insectivorous kinds would more than pay the orchardist for his trouble
in their behalf by feeding upon the insects that injure his trees;
while fruit-eating species, like the linnet, being able to quench their
thirst with water, would not be compelled to resort to fruit for this
purpose.

The writer once observed a leaky hydrant situated between two
rather extensive areas of orchards. The little pool maintained by the
drip of this pipe was almost constantly surrounded by birds which
all the time were coming and going, so that the number that visited
it each day must have been well up in the thousands. An arrange-
ment for this purpose need be neither elaborate nor expensive, and
would serve a useful purpose.

READJUSTMENT OF CONDITIONS.

In relation to the destruction of crops by birds in a comparatively
newly planted region, experience everywhere shows that after a time
there is a partial readjustment of conditions, so that inroads by birds
become much less common or wholly cease. On the Atlantic side
of the continent at the present time, with the exception of the
ravages of bobolinks in the rice fields of the southeastern coast States,
few if any cases are known of the annual destruction of crops by
birds, while during the first half of the nineteenth century the
several species of blackbirds were a constant menace to grain. Pres-
ent immunity results from the fact that increased density of popula-
tion has destroyed the nesting sites and reduced the numbers of some
of the most noxious birds. This readjustment of conditions is likely
to take place sooner or later in all cases where the balance of nature
is disturbed, but in most cases the process may be hastened by the
adoption of measures like the ones above mentioned.

DAMAGES BY -BIRDS GENERALLY.

Study of a number of cases of serious damage by birds leads to the
conclusion that as a rule such damage is due to the concentration of
a great number of birds within a limited area, usually of a single
species or several closely allied ones. If the birds are seed eaters,
they visit the grain fields and leave ruin and destruction in their path;
if fruit lovers, they seek the orchard and play havoc with the crop.
Instances of this kind are the raids of bobolinks in the rice fields of

HOUSE FINCH. Le

the southeastern Atlantic coast, of the blackbirds in the grain fields
of the Mississippi Valley, and of the linnets in the fruit orchards of
California. It is seldom that complaints are made of birds in gen-
eral; one or a few species are usually the culprits, the reason for
which is evident—too many individuals of the same species in one
locality eating the same things. But when many species are present
in normal numbers, such a variety of tastes is to be gratified that no
one kind of food is unduly drawn upon.

BIRDS THAT INJURE- FRUIT IN CALIFORNIA.

When a fruit grower in northern California is asked what birds are
most injurious to his crops, he almost invariably mentions first the
linnet, or house finch; then successively the blackbird, the oriole, the
grosbeak, and the thrush. Or, if his ranch is in a narrow valley or
canyon, or near wooded hills, he may place the California jay or the
quail after the linnet as the next worst enemy to fruit.

The writer is pleased to be able to testify to a healthy state of
feeling on the part of the great majority of California fruit growers
toward the bird population. While many of them stated that they
still suffered loss, none advocated measures for the extermination, or
even the material decrease, of birds. The feeling seems to be prac-
tically universal that birds as a class, notwithstanding their sins,
still do more good than harm. “ We can’t get along without the
birds,” was the sentiment voiced by many and really indorsed by all.

HOUSE FINCH.
(Carpodacus mexicanus frontalis.)

The house finch, or lnnet, has been perhaps the subject of more
complaint on the score of destroying fruit in California than all
other species of birds together. This bird occurs on the western
coast of the United States from Mexico northward to Oregon, and
extends eastward to the western edge of the Mississippi Valley.
Except in the mountains, it is a resident throughout most of Cali-
fornia, but in certain parts of the northern half of the State it dis-
appears for a few months during the winter season. In the southern
half and in the warm sheltered valleys of the north it is always
present. It is a hardy, vigorous species, well able to take care of
itself and maintain its ground wherever it obtains a foothold. It is
a prolific breeder, raising several broods in the season, and apparently
has no enemy (except man) that exercises any perceptible restrictive
influence upon its increase and distribution. It takes kindly to the
presence of man, and utilizes his improvements for shelter and food,

14 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

DESTRUCTION OF FRUIT.

Observations in orchards show that in the fruit season the linnet
is not backward in taking what it considers its share of the crop, and
as it spends much of the time there, field observations alone would
lead to the conclusion that fruit was its principal article of diet.
Examination of the stomach contents, however, proves that such is
not the case, and when we find how small is the relative percentage
of fruit eaten, it seems strange that its fruit-eating proclivities should
have attracted so much attention. But it must be borne in mind that
the bird is wonderfully abundant, which is one of the primary condi-
tions necessary for any species to become injurious.

Like most fringilline birds, the linnet has a strong, conical beak,
with which it can cut the skin of the toughest fruit and reach the
pulp. While such an instrument is very effective in attacking fruit,
this is evidently not the use for which nature primarily designed it.
It is customary to divide passerine birds roughly into two groups,
the hard-billed and the soft-billed species, the former of which are
supposed to feed on seeds while the latter subsist upon fruit and
insects. From the standpoint of this classification the linnet would
appear to be most emphatically a seed eater, and examination of the
contents of stomachs of the species confirms the correctness of this
view. Seeds of plants, mostly those of noxious weeds, constitute about
seven-eighths of its food for the year, and in some months amount to
much more. In view of this fact it seems strange that the house
finch has acquired such a reputation for fruit eating, and it can be
explained only upon the principle already laid down that in the fruit
districts the bird is too numerous for the best economic interests.
While each house finch eats but a small modicum of fruit, the aggre-
gate of all that is eaten or destroyed by the species is something
tremendous.

Moreover, it must be noted that not all of the fruit destroyed is
eaten. Only one peck from the strong bill is necessary to break the
skin of the pear, peach, or cherry, and the fruit is spoiled; the linnet
by no means invariably visits the same individual fruit a second time
to finish it, but often attacks a fresh one at each meal. This is proved
by the large number of half-eaten fruits, either on the tree or on the
ground beneath.

In large orchards, however, complaints against the linnet are fewer
than formerly. Here the damage is more widely distributed and con-
sequently less noticeable than when confined to a few trees. It is
probable that the area of orcharding has increased more rapidly than
the linnets, so that the proportional injury is less. At present the
chief complainants are the owners of small town lots, where a few
trees are grown to supply fruit for home use. As linnets are usually

HOUSE FINCH. 15

more numerous in villages and suburbs than in the country, trees in
gardens are often entirely stripped.

INJURY TO FRUIT BUDS.

It is a little simgular that formerly most of the complaints against
the linnet were that it destroyed the buds and blooms of fruit trees
instead of the fruit itself. Thus in 1886 Mr. R. P. Chandler, of
Riverside, San Bernardino County, wrote:

The bird which is commonly known as the linnet, or crimson house finch, has
been observed to do great injury to the apricot crops of this section by feeding
on the fruit buds from the time they begin to swell until the trees are in bloom.
Two years ago my, entire apricot crop was destroyed by the above birds, and I
took the opportunity to establish the facts of the case by shooting a large num-
ber for the purpose of examination. A great many of the birds that were shot
had small bits of buds, ete., stuck on their bills by the gummy substances of the
fruit buds. <A further examination would invariably result in finding each and
every bird’s stomach filled with buds.

The same year J. C. Galloway, of Tustin, Cal., stated:

The common linnet does great injury to the buds of the apricot, eating out
the center and destroying all the fruit buds on the tree in many cases, usually
in January and February, in this latitude.

William Proud, of Rancho Chico, Cal., accuses the linnet of eating
both buds and fruit. He says:

The burion, house finch, or linnet, is by far the most pernicious bird we have
to deal with in the orchard. He arrives in March and immediately commences
his ravages on the buds of the cherry, peach, plum, persimmon, etc. The first
cherry showing a red cheek is sampled by this most rapacious little bird. Then
comes the fruit of the apricot, peach, and fig. For the latter he shows a decided
partiality. When the fruit crop is exhausted he immediately turns his atten-
tion to all kinds of millets, sorghum, Egyptian corn, and other small seeds.

As showing how destructive the bird is to fruit, especially in small
orchards, the following is quoted from Dr. T. S. Palmer, then at
Berkeley, Alameda County, Cal.:

The crimson house finch is the only bird that does any considerable damage
to fruit. As soon as the cherries begin to ripen the birds keep close watch of
the trees, and if the fruit is not gathered as soon as ripe they soon dispose of a
large portion of it. In our garden there are about a dozen cherry trees of
various kinds, and if not very closely watched, within a week or two from the
time when the fruit first begins to ripen almost every tree will be completely
stripped. Of course, in a large orchard the damage would not be so noticeable,
but still might be considerable. Later in the season when the cherries are
gone, the finches attack the plums and pears.

F. H. Holmes, of Rio Vista, Solano County, Cal., under date of
September, 1886, states:

Our worst fruit pest is the crimson house finch, which, on account of its
abundance and familiarity, it is impossible to scare off. They injure mostly
cherries, figs, berries, peaches, and apricots. They often only peck each fruit

16 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

a little, and then the bees and wasps take hold and finish the work. * * *
Birds that destroy the earlier fruits are generally regarded as the greater
nuisance, particularly to the farmer who has not a very extensive orchard.
Where fruit is handled as soon as it is in the proper condition, or for an orchard
of from ten to one hundred acres or more, 1 have never seen these birds plenti-
ful enough to do a great amount of damage. In some parts of the State I
presume they might do more.

In regard to the habit of the linnet of eating ripe fruit, Dr. A. K.
Fisher says:

In this valley [Owens], both at Independence and Lone Pine, the species
[the linnet] was found to be very destructive to the ripened peaches during the

middle of August. Flocks of birds occurred in the orchards, and in some
places hardly an example of the ripe fruit could be found which was not more

or less mutilated. A number of birds shot in the peach orchards at Lone Pine .

had little except the pulp of this fruit in their gullets or stomachs. It was
known as the ‘ peach bird.’ @

Examination of linnet stomachs does not reveal any very consid-
erable number of blossom buds, and it is probable that but little of
the alleged mischief to fruit blossoms is done by this bird. Moreover,
it may be stated that in most cases budding by birds does little, if
any, damage. It is only in very rare instances that birds take all
the buds from a tree, or even enough to cause considerable loss. On
the contrary, buds are usually superabundant, and budding, whether
by birds or by man, is frequently beneficial, relieving the trees from
excessive bearing and markedly improving both size and quality
of fruit.

THE LINNET NATURALLY A SEED EATER.

Before the settlement of the Pacific coast region it is evident that
the linet must have subsisted almost entirely upon the seeds of
plants growing wild in the valleys and canyons. With the advent
of civilization two new articles of food were presented—grain and
fruit. It would seem natural for the linnet, especially equipped as
the bird is to extract the kernel of seeds, to have chosen the former,
as did the blackbirds, doves, and some other species; but for some
reason best known to itself it selected fruit. How much the char-
acter of the food had to do with the bird’s choice it 1s impossible to
say, but it is probable that attendant conditions greatly influenced
the result. Grain is grown on large, open areas, with few or no
trees to afford nesting sites, while orchards offer every inducement
to linnets as a permanent residence. Moreover, much of the fruit-
growing section of the State is divided into small holdings, each with
a dwelling with accompanying barns, sheds, and other buildings that
afford ideal homes for these birds. Having thus chosen the orchard

a@North American Fauna No, 7, U. S. Dept. of Agric., p. 80, 1893. :

Buil. 30, Biological Survey, U. S. Dept. of Agriculture. PLATE Il.

Fig. 8.

SEEDS OF COMMON WEEDS EATEN BY THE LINNET.

Fig. 1.—Napa thistle ( Centaurea melitensis). Fig. 2.—Black mustard ( Brassica nigra).
Fig. 3.—Alfilaria (Erodium cicutarium). Fig. 4.—Knotweed ( Polygonum aviculare).
Fig. 5.—Tarweed (Madia sativa). Fig. 6.—Burweed (Amsinckia tesselata). Fig. 7.—
Turkey mullen ( Eremocarpus setigerus). Fig. 8.—Milk thistle (Mariana mariniana).
Fig. 9.—Poison oak ( Rhus diversiloba Ne

HOUSE FINCH. tr
for its home it was only a matter of course that the bird should
select as its secondary food the nearest available source of supply,
namely, fruit. For seeds, which are to be regarded as the linnet’s
natural food, grow about the borders of orchards and by roadsides,
and hence are readily obtained.

Although the great bulk of fringilline birds normally subsist
principally upon seeds, at certain times, notably in the breeding
season, they eat a considerable quantity of animal food, mostly
insects. Moreover, their young while still in the nest are usually
fed largely, and in some cases entirely, upon insects. Quite the con-
trary is true of the linnet. The adults eat only a small percentage
of animal food, even in the breeding period, and feed their nestlings
no more, perhaps less, than they eat themselves. In this respect the
linnet is probably unique in its family. Such animal food as the
bird does eat, however, is much to its credit. Plant-lice (Aphide),
especially the woolly species, constitute a large portion of this part
of the linnet’s food; caterpillars and a few beetles make up most of
the remainder.

It is, however, as a seed eater that the linnet stands supreme.
Over 86 percent of its food for the year consists of weed seeds, and it
is in this field, if anywhere, that the bird redeems itself from the
odium of its other misdemeanors. When the immense number of
linnets in California is taken into consideration, with the added fact
that each one destroys several hundred seeds daily, most of which are
potential weeds, it must be conceded that the bird renders a valuable
service to agriculture, for the sum total of weeds so destroyed is
enormous.

FOOD.

In the laboratory investigation of the food of the linnet 1.206
stomachs were examined, including 46 of nestlings. All were from
California, and from points fairly well distributed over the State,
with the exception of the northern quarter. The greater number were
from the fruit-growing sections, so that the western coast region
is better represented than the part east of the Coast Ranges. They
were distributed through the year as follows:

ety So IS sense On, |MAUSHSE Sos Seep aay ey a | 118
0 he oe iy MSc) 9) 02) 00 0] ee oe ea a 93
oD Sa ee a ee pie pee PeGal October ss en ee A 108
I 8h A ee z SOC LING VOMIUCN 5500 = 52 ng ees 25
Ee es el aan Re ae a OE, | SLCC INDO A aa ss Se es 54.
0 _ SS ee eee 167 -
Lea re 148 | WO ta Tes eee ee eee 1, 206

9379—No. 30—O07

18 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

In the first analysis of the food components the two principal
elements are found to be: Animal matter, 2.4% percent; vegetable
matter, 97.6 percent.

Animal food.—This brings into strong relief the lnnet’s sins of
omission. Living in a country where constant war against noxious
insects is necessary, the bird takes little or no part in the contest, and
in return for benefits derived from man renders but shght service in
this direction.

The small portion of animal food it takes, however, consists almost
wholly of insects and a large proportion of it of plant-lice (Aphi-
cide), which from their small size do not attract the notice of many
species of birds. They appear, however, to be the favorite animal
food of the linnet, and it is noticeable that a large percentage of them
are the woolly species. Many of the birds when lilled had their
beaks smeared with the remains of woolly aphides. As these insects
are notoriously harmful to many trees and other plants, any bird that
destroys them is a benefactor. It is to be regretted that the linnet
should not indulge to a greater extent a taste so well directed. Were
25 percent of its food made up of woolly aphides the fruit it destroys
would be well paid for. The other contingent of animal matter
found in the linnet’s stomach consists of small caterpillars and a few
beetles, chiefly weevils. Most birds that feed on plant-lice eat also
the ants that are usually in attendance upon them, but the only trace
of ants or of other Hymenoptera in the stomachs of linnets was one
ant’s jaw. Grasshoppers, the favorite food of so many birds, were
represented by a mere fragment in one stomach.

Vegetable food—The most interesting part of the food of the lin-
net is the vegetable portion. This naturally falls into three cate-
gories: Weed seed, which amounts to 86.2 percent of the annual food;
fruit, 10.5 percent; and other miscellaneous vegetable matter, 0.9 per-
cent.

Fruit.—Fruit is represented in stomachs taken in January by a
mere trace. This was probably of no value, only ungathered fruit or
perhaps belated olives. In stomachs taken in February no fruit was
found, but in ensuing months it appears in small quantities, increas-
ing irregularly until August, when a maximum of 27.4 percent was
eaten. In September a trifle less was taken than in August, and after
that the quantity decreases until December, in which month a little
less than 2 percent was eaten. In March the fruit amounted to
about 6 percent, a quantity hard to account for except on the suppo-
sition that it was waste fruit left over from the previous year. The

a While percentages are sometimes given in fraction, it need not be assumed
that extreme accuracy is intended; such figures must be taken as only an
approximation to the truth.

—

HOUSE FINCH. 19

amount eaten in this month is somewhat surprising in view of the
fact that in April less than 2 percent was consumed, and it is not until
June that the percentage becomes important. It is possible that the
supply of weed seed of the previous year may be exhausted by March,
when the new crop has not yet ripened; so waste fruit is taken for
want of something better.

It is practically impossible to identify particular kinds of fruit in
a bird’s stomach unless characteristic seeds or stones are present.
These are rarely eaten by the linnet, which seems to prefer orchard
fruit. Cherries, apricots, peaches, and prunes appear to be the favor-
ites. This choice arises, no doubt, from the character of its beak
already described. While thrushes and other * soft billed’ birds pre-
fer the smaller kinds commonly known as berries, which can be swal-
lowed whole, the linnet attacks the larger kinds, which yield readily
to its powerful beak. Linnets are particularly fond of small pears,
like the Seckel, and often attack them even when they are hard, a
fortnight or more before ripe. If undisturbed they will eat every one
on a tree, leaving the core attached to dry and blacken in the sun.

A few strawberries and fewer blackberries or raspberries were the
only cultivated small fruits that could be identified in the stomachs
of linnets. A number of birds from the southern part of the State
had fed freely on figs, identified by their seeds.

If the bird preferred an exclusive diet of fruit, there is no reason
why its taste should not be gratified during the greater part of the
vear. When cherries are ripe in California lnnets need eat nothing
else. The cherry crop would be ample for all their wants, though
perhaps not much would be left for marketing. The record, how-
ever, shows that in June, which is practically cherry month in the
central part of the State, less than one-seventh of the linnet’s food
consists of fruit. Apricots are ripe in many parts of the State
before the month closes, so that lack of fruit can not be urged as a
reason why the bird should subsist so largely upon weed seed. In
July apricots, peaches, and early figs are available, but still the linnet
eats them only to the extent of one-fifth of its diet, and even in
August and September, the months of maximum consumption, fruit
constitutes only a little more than one-fourth of the food.

Weed seeds.—The greater portion of the linnet’s food, as already
stated, consists of the seeds of weeds, the most important of which
are those of the Napa thistle, black mustard, Alfilaria, knotweed, and
turkey mullen (see Pl. I, figs. 1, 2, 3,4, 7), the total consumption of
which for the year is 86.2 percent. This record is not excelled by
that of any other bird studied, with the possible exception of the tree
sparrow (Spizella monticola), whose food, however, consists largely
of grass seed, much of which is useful. As there is an unaccountable

20 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

increase in the fruit eaten in March, so there is an unexplained de-
crease in the consumption of weed seed during that month. With
that exception, the amount taken m each month decreases in a fairly
regular series from a maximum of 99.8 percent in January to a mini-
mum of 64 in August. From this month the quantity of seed in the
stomachs increases steadily to December, when the record ends with
97.9 percent. |

It seems probable that such a constant and persistent eater of weed
seed would also eat considerable grain. Stomach records show that
wheat was identified in one stomach, oats in three, and something very
like the skin from kernels of corn in five. In this connection it can
be said that if the linnet does not eat grain it certainly is not for want
of opportunity. It is evident then that weed seed is taken by the
lnnet simply because it likes it.

SUMMARY.

It is natural to conclude that the food most frequently found in a
bird’s stomach is the kind preferred. Applying this test to the linnet
we find that of the total 1,206 stomachs examined, 1,133, or 94 percent
of all, held weed seed, and that 807, or nearly 67 percent of the whole,
contained no other food. On the other hand, fruit was found in 297
stomachs, or 24 percent of the whole number, but only 38, or 3 per-
cent of all, were entirely filled with it. In other words, there were
only 63 stomachs that did not contain weed seed, while 909 contained
no fruit.

The miscellaneous portions of the linnet’s vegetable food amount
to only about nine-tenths of 1 percent of the food.of the year. and
all was found in 28 stomachs. Stamens and other parts of flowers
were found in 14 stomachs only, which does not indicate that the
injury to fruit buds by the lnnet is serious. One stomach contained
a small leaf gall. Ten stomachs held matter denominated as rubbish,
consisting of bits of dead leaves, rotten wood, etc., evidently swal-
lowed unintentionally with other food.

From the foregoing it appears that, contrary to the statements and
beliefs of many, the linnet is not a constant and persistent devourer
of fruit. Examination of the contents of many stomachs shows that
fruit is far from being its principal article of diet, and it is probable
that what is taken is eaten for the sake of variety or for the Juice. “A
far greater quantity of fruit is eaten by the cherry bird (Ampelis
cedrorum) and by the robin (Merula migratoria), both of which occur
in California.

PROTECTION OF FRUIT FROM LINNETS.

In the case of both these birds, however, the greater part of the
fruit eaten consists of wild species, and this fact suggests a method

HOUSE FINCH. yi |

by which the California fruit grower may protect his orchards from
the attack of the linnet—namely, by planting around orchards shrubs
and trees the fruit of which will serve to attract birds away from
the marketable kinds. There are many fruit-bearing shrubs and
trees whose products, while worthless to man, are likely to prove more
attractive to linnets than are the orchard fruits. That linnets will
eat wild fruit appears from the fact that elderberries (Sambucus)
were found in 49 stomachs, and their apparent partiality for culti-
vated fruits is readily explained by the fact that usually they are
the only kinds obtainable. ‘

FOOD OF YOUNG LINNETS.

Of the 1,206 stomachs of linnets included in this investigation, 46
were those of young birds taken from the nest. The young vary in
age from birds 2 days old to those nearly ready to fly. In order to
ascertain the exact difference, if any, between the food of the nes-
tlings and that of the adults, the contents of these 46 stomachs were
tabulated by themselves and the percentages of the various items of
food calculated. The results show 2.4 percent of animal food to
97.6 of vegetable. The animal food consists mostly of the larve of
a minute beetle which lives on decayed fruit, with a few plant-lce
and one small fragment of a grasshopper, the only one found in any
of the stomachs. The vegetable food consists entirely of weed seed,
the most important of which are the following: Sunflower, bur weed,
milk thistle, and poison oak. (See Pl. IT, figs. 6, 8, 9.)

No fact connected with the food habits of the lnnet is more sur-
prising than this. The great body of the fringilline birds, though
subsisting largely and in most cases almost entirely upon vegetable
food in adult life, feed their young in the early stage of existence
almost exclusively upon insects or other animal food, and begin to
give them vegetable food only when nearly ready to leave the nest.
It is doubtful if there is an exception to this rule so pronounced as the
linnet. As calculated, the nestlings ate actually less animal food than
their parents, but the difference is so small that it may be aecidental.

ECONOMIC PLACE OF THE LINNET.

Admitting, as we must, that the orchardist has just grounds of
complaint against the linnet on account of depredations upon fruit,
the bird’s claim to favorable consideration must rest upon its valuable
services as a consumer of weed seed and upon its esthetic value. It
is trim and pretty, has a sweet song, and in many ways is a pleasing
adjunct of rural lfe—in fact, many Californians believe that the
linnet, in spite of its sins of commission and omission, should be

22 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

protected. That the complete extermination of the species, even if
possible, is not desirable will be readily allowed, but that a reduction
of its present numbers would be for the general welfare can not rea-
sonably be denied. Were it possible to destroy half the lnnets in the
fruit-growing sections of the State, there is no doubt that most of the
complaints against the species would cease. As it 1s, the fruit grower
must protect himself by such devices as are suggested by local con-
ditions, and bear in mind that, while as an individual he may suffer,
the bird, on the whole, is doing the State good service.

LIST OF SEEDS FOUND IN STOMACHS OF LINNETS.

Following is a list of identified seeds, with the number of stomachs
in which each kind was found. The same kinds of seeds were of
course contained in many more stomachs, but were so finely ground
up as to be unidentifiable. It is not unlikely that in identifying the
seeds specifically errors have been made, but it is believed that few,
if any, of the generic identifications are erroneous. A few seeds
were found which have not yet been identified.

EUS EHICORETUS a! kL EDS 2 aD EP Nae ee mee ee a Se 21
SOEKele Ghee MCCLOSEULG et Ss ie ee ee 3
Knotweed. (Lolygenum aviculare)... (Rl. 1, fig. Aye a eee eee 128
iSatentiy: jCOStlene SD.) 2m 2282 eS HUE Mir, soe RIE RN 571!
Chickweed (Stellaria media) ~~-_~_____ ares he AS Pee 21
SPuUEry. (SPergqula arvensis) w= ese = eee SUD ei ik, sere eA a eee 14
Amaranth (Amarantus retroflexus et al.) -_____—_ EEA ee et deine ye le 108
Galandrinia (Calandrinia menciesi) es 2] a2. See SU tee 2
Minerisjethice. (itontia perfoliata) 2:. ei ae eee eee eee 11
Wild turnip (Brassica campestris) ——_—~ Se ae ae oy he eae SP ole 13
Black mustard (Brassicawuora). ¢CPin We fis: 2) =e ee ee ae ae ee 83
Wald radish, CRaGDLGNUS SAUIbUS) es eee ee 108
Geranium’ (Geranium. dassectim) 22h 2s — 2 ee ee ee 3

MAnlariae (| HrOdiimn MOsChatuM) =e eo a eee |
Alflariat (Hrodvieun cicutartum).. GPs Ty fig? 3) ee eee eee eee

Menow Sorrel. (O7calis: cornmculai@) 22 ee ee ee eee Wedyt Saale 1
Turkey mullen (Hremocarpus setigerus). (PI. II, fig. 7)-------- Ee ee 117
Powon oak Chius diversilota).. CPT. Ii, fic: 9).=.e22—3 aj a ee 1
surweea (Amnsincha tesselata). “CEL Ils tie -6)22> = », £5, STS ge cae =
Nightshade (Solanum nigrum) ~~~ ~~ CPOE ee CLL? REET ne 4
Western ragweed (Ambrosia psilostachya) 2-2 a ee eee 3
Sunflower (Helianthus sp.) —-~--------- SEE eee 22 3 ek Sie Ha)
Mayweed (Anthemis cotula)—_-_--_---____-_- Dy le Sa ee 1
Groundsel. (Senecio vulgaris) 2.2 22 sea ee a 3 Las ee 21
Lesser tarweed (Deinandra fasciculata) ————~ i Se, oe ie 1
Tarweed (Madia sativa). (PI. II, fig. 5)—----_-— : at 5
Milk thistle (Mariana mariniana). (PI. II, fig. 8)------- oe ee ae

Napa thistle (Centaurea melitensis). (Pi 11, ig. 1) -_---__ eee 60

WESTERN TANAGER. 23

The following table shows the percentages of the various items of
food of the linnet for each month of the year:

Table of percentage of food of the linnet for each month in year.

Vegetable food eaten.

Number of} Animal
Month. stomachs food | weed
examined.| eaten,

; | Total
atk Miscel- |... .
seed, Fruit. | janeous, |Yosetable

food.
Percent. | Percent. | Percent. | Pereent. | Percent.

TDG Ta ie fee ae ER ee 3 eg 88 | 0.0 99.8 0. 2 0.0 100.0
RMR CULO lett cs a hee ae od Marka Sais wake 30 2.9 97.1 0.0 0.0 97.1
LD ee SN 2 is ee eee Pa 186 1.0 89.5 5.8 3.6 | 99.0
ST a SR I ees ae ee 80 8 92.5 ti 0.0 | 94.2
We Ee ne ae ieee pe 74 6.3 §8.9 4.8 0.0 93.7
BURY Ce ope ete ee wie Sana Saas Swan 167 3.9 81.6 13.4 1.2 96.1
RRR eee re eee ea ee ee 148 re 76.5 19.7 1.5 97.8
J TESTE Ra itp ae ES ee aa oa ee 118 (eal 64.0 27.4 1.5 92.9
BIENIEE NYP eek eee ee om oe els a ale 123 0.1 71.6 26.7 1.6 | 99.9
TATE 0] aD Sue SR lal NMS My ip ae oe 108 0.0 83.5 15.6 0.9 100.0
iON GY pC) ie ee er ean eae eee 25 0.0 91.7 8.3 0.0 | 100. 0
OCT DS OR Ee a ee eee ge 4 0.0 97.8 1.8 0.4 | 100.0

ANGIE ee ee a eS W206 Woe See [ee 2 ocecs alae os See | Cee

PQ Ee a RS a ee 2.4 86. 2 10. 4 0.9 97.5

WESTERN TANAGER.
(Piranga ludoviciana. )

The western tanager, like the robin, occasionally becomes a nuisance
in the orchard. It breeds in the mountainous regions of California
and northward, and as a rule is not common in the fruit-growing
sections.

DAMAGE TO CHERRY CROP.

There are, however, times during migration when it fairly swarms
in some of the fruit-raising regions, and unfortunately this sometimes
happens just at the time when the cherry crop is ripening. The bird
is a late breeder and does not seem to care to get to its nesting ground
before the last of June or early July. It is thus enabled to begin in
the southern part of the State when cherries are ripening there, and
leisurely follow the ripening fruit northward. The year 1896 wit-
nessed an incursion of these tanagers, when they swarmed over much
of the State and destroyed a large part of the cherry crop.

Probably the best account of this occurrence is that of W. O. Emer-
son (published in the Condor, Vol. V, 1903, p. 64). Ma. Emerson
says:

One of the most wonderful occurrences of the movements of birds in the sea-
son of migration which ever came under my notice, took place at Hayward
during May, 1896, when countless numbers of Piranga ludovicianda, or Louisiana
tanagers, began to make their appearance between May 12 and 14. From the
18th to the 22d they were to be seen in endless numbers, moving off through the
hills and canyons to their summer breeding range in the mountains. This con-
tinued till the 28th, and by June 1 only here and there a straggling member of

24 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

the flock was to be seen. They were first found feeding on early cherries, in
an orchard situated along the steep bank of a creek, on the edge of rolling hills,
well covered with a thick growth of live oaks, which faced the orchard on the
east. To this thick cover they would fly, after filling themselves with cherries,
and rest till it was time to eat again. ‘This they weuld keep up from daylight
to dark, coming and going singly all day, without any noise whatever being heard.

Two men were kept busy shooting them as fast as they came into the trees
which lay on the side next to the oak-covered hills. * * * After the first
week, I found on going here (May 17), that dozens on dozens of the birds were
lying about. * * * Tanagers lay about everywhere, and no doubt many must
have fiown off to die in the bushes or on the hillsides. * * * JI noticed one
fact of the restriction of the tanagers to the orchards along the hill edges. None
were found, so to speak, in the larger orchards abouc the town of Hayward.
* * * Mr. H. A. Gaylord, of Pasadena, Cal., in a letter under date of June 16,
1896, states that “they were seen singly from April 23 to May 1. From this
date up to May 5 their numbers were greatly increased, and by May 5 there was
an unusually large number of them. Then for about ten days, until May 16,
the great wave of migration was at its height. Tanagers were seen everywhere,
and noticed by everyone. After May 20 they decreased in numbers, and by
May 26 the last ones had left the valley.” * * * Healso says: ‘‘ The damage
Gone to cherries in one orchard was so great that the sales of the fruit which
was left, did not balance the bills for poison and ammunition. The tanagers
lay all over the orchard, and were, so to speak, ‘corded up’ by hundreds under
the trees.”

There must have been thousands of tanagers destroyed all through the path
of their movement along the State, as they worked their way to the breeding
grounds.

Here are two accounts of this great flight of tanagers—one from
Pasadena, the other from Hayward, 330 miles farther north as the
bird flies. The time taken by the tanagers in traversing this dis-
tance was only eight days, so it would appear that individual birds
did not spend much time in the same orchard. Such sporadic flights
are hard to account for. The tanagers are in California every year,
and every year they migrate to their nesting grounds in spring and

ERR

return in fall, but only at long intervals do they swarm in such .

prodigious numbers. Evidently the migration ordinarily takes place
along the mountains where the birds are not noticed. It is possible
that in some years the mountain region lacks the requisite food, and
so the migrating birds are obliged to descend into the valleys. This
would seem to be the most plausible explanation of the occurrence—
that is, that the usual line of migration is along the Sierra Nevada,
Lut some years, owing to scarcity of food, or other cause, the flight
is forced farther west into the Coast Ranges, where the birds find
the ripening cherries. The damage done by this species, however,
is not confined exclusively to the rare occasions when they appear in
such extraordinary numbers. R. H. Carr, of Redlands, southern
California, wrote us in June, 1899:

Without examining any stomachs it is easy to report the value of the Louisi-
ana tanager to the fruit growers near here. In the city they seem to keep

WESTERN TANAGER. 25

almost entirely on the Grevillea trees, sipping the sweet liquid that exudes
from the blossoms. But the Andrews Brothers, whose cherry and apple ranch
is in the upper Yucaipe Valley, report that the tanagers destroyed about $4,000
worth of cherries, being almost the entire crop. They used powder and shot
liberally, but did not save the crop.

It is to be regretted that some of the stomachs of these tanagers
were not saved, in order that the diet of the species might be ascer-
tained with precision. The only material available for examination
consists of 46 stomachs from various parts of the State, during the six
months from April to September, inclusive. This number is entirely
too small to afford positive data as to the regular food habits of the
bird, but undoubtedly points in the right direction. Although the
testimony of field observers shows that this tanager eats a good deal
of fruit, analysis of the stomach contents proves that over 82 percent
of the food for the six months indicated above consists of insects, and
the remainder, nearly 18 percent, of fruit, with a mere trace of seeds of
a conifer.

Insect food.—The largest item of the animal food is Hymenoptera,
most of which are wasps, with some ants. Altogether they amount to
56 percent of the food for the six months, and in August they reach
75 percent. (They reach 92 percent in April, but only one stomach
was taken in that month, so the record is not reliable.) Hemiptera
stand next in importance, with 8 percent. They are mostly stink-
bugs, with a few cicadas. Beetles amount to 12 percent of the food,
of which less than 1 percent are useful Carabidae. The remainder
are mostly click-beetles (Elateride) and the metallic wood-borers
(Buprestide), two very harmful families. The former in the larval
stage are commonly known as wireworms, and bore into and destroy
or badly injure many plants. The Buprestids, while in the larval
stage, are wood-borers of the worst description. (Grasshoppers were
eaten to the amount of 4 percent, and caterpillars to the extent of less
than 2 percent.

Fruit——tThe greater part of the fruit eaten appeared to be the pulp
of some large kind like peaches or apricots. One stomach contained
seeds of elderberries; another the seeds and stems of mulberries, and
two the seeds of raspberries or blackberries. Nearly all these
stomachs were collected in the mountains, away from extensive
orchards, but still the birds had obtained some fruit, probably
cultivated.

SUMMARY.

It is evident from the testimony that great damage from this
species occurs only at rare intervals and during the spring migration.
The greatest losses occurred in May, 1896, when the damage to the
cherry crop in certain localities was most disastrous. As, under ordi-
hary circumstances, the greater part of the food of this bird consists

26 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

of insects, many of them harmful, the tanager has a fair claim to con-
sideration at the hands of the farmer and even of the orchardist.

It is probable that means may be found to prevent, at least in part,
the occasional ravages of the tanager on the cherry crop. The tan-
ager, like the robin, prefers to swallow fruit whole, and as the latter

oie: small wild cherries in preference to the larger, cultivated kinds

when both are equally accessible, it is probable that the tanager would
do the same; and it is suggested that a number of wild cherry trees
planted around California orchards might prove an economical in-
vestment for the orchardist.

SWALLOWS.

Swallows are the light cavalry of the avian army—always on the
move, always on the skirmish line, ever gathering stragglers from
the insect camps. They furnish another instance, and perhaps the
most remarkable one, of change of habit induced by civilization.. In
eastern United States the bank swallow and the rough-wing are the
only species that adhere persistently to their original nesting sites.
In the West a third species may be added to these, the violet-green
swallow; but there all the swallows are somewhat less domestic than
in the East. It is probable, also, that some species, notably the barn
swallow, are more abundant than when the country was unsettled,
owing to the increased number of nesting sites. Supposing for a
moment that the country was swept bare of buildings, where could all
the barn swallows find suitable places to nest? The chff swallows
might discover enough overhanging cliffs upon which to attach their
mud domiciles; the white-bellied and the martin, as formerly, might
nest in the hollows of trees, but there are not caves enough east of
the Mississippi River to afford nesting places for one-tenth of the
barn swallows. In the far West they would fare better. When the
country was first settled, barn swallows must have been confined to a

few rocky cliffs and caves here and there along the seashore or in
mountains. Now they live wherever man has erected a structure of
anv kind.

As is to be inferred from the movements of these birds, their food,
with some curious exceptions, consists principally of insects caught
in mid-air. For this reason all the species are migratory, except 1n
the Tropics, for the food supply fails in regions where frosts prevail.
As many insects that usually do not fly, periodically ‘swarm, they
are often captured by swallows at such times in great numbers. Such
is the ease with ants and ‘ white ants’ (Termitide), which most of
the time are concealed in the earth or in logs, but at certain times
‘swarm’ in immense numbers. Many species of beetles that live in
offal and ordinarily are not accessible to birds, in case of failure of

SWALLOWS. 27
food, migrate in great numbers, and then are preyed upon by swal-
lows, flycatchers, and other birds. The destructive cotton boll weevil
is more or less active during the late summer and early fall months,
and it has been learned that the swallows, as they pass through the
cotton States on their way to their southern winter quarters, catch
great numbers of them on the wing and so perform an exceedingly
important service. Engraver beetles (Scolytide) have frequently
been found in the stomachs of swallows. These insects live under
bark, and generally are inaccessible to birds, except woodpeckers ;
periodically they migrate from the tree where hatched and matured
to search for fresh pastures; at such times they are unprotected and
fall easy prey to any fly-catching bird. Swallows are peculiarly
adapted to capturing small insects in mid-air. While their bills are
weak their mouths are wide, and their long wings enable them to fly
swiftly and turn quickly, so that they sweep back and forth through
a swarm of insects and gather them by hundreds.

Seven species of swallows, with several subspecies, are commonly
found within the limits of the United States. Their food habits
rary but little. All seven species occur in California, and this num-
ber includes one, the violet-green, that does not occur in the East.

3esides the swallows whose food will be discussed in detail in the
following pages, a few stomachs of the tree swallow (/ridoprocne
bicolor), the western martin (Progne subis hesperia), and the bank
swallow (Riparia riparia) have been examined, but the number is
entirely too small to be used as a basis for general conclusions were
it not for the fact that their contents agree in all essential points
with those of the other swallows, of which a greater number were
available for examination. In fact, it may be said of all the members
of the swallow family that they subsist upon practically the same
kind of food, with shght variation from month to month. It may
be laid down as a general rule that the food of all American swal-
lows is derived from the following orders of insects: Coleoptera,
Hymenoptera, Hemiptera, and Diptera, with a few individuals from
one or two other orders, and an occasional spider. So far as present
investigation has shown, 90 percent of their animal food is from the
four orders named above, but the relative proportion of each varies
somewhat with the different species and seasons. With one notable
exception ® the swallows take so little vegetable food that it may be
passed by as a negligible quantity, and much even of the little eaten
is probably swallowed accidentally.

After the above statements in relation to the food of the swallows,
it is perhaps unnecessary to dwell upon the great value of these birds

aThe tree swallow of the East (Jridoprocne bicolor) during its southern
migration freely eats the berries of the bay-berry (J/yrica carolinensis).

28 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

as insect destroyers. They do not consume any product of hus-

bandry, and the worst that can be said of them is that they eat some

useful insects with the harmful ones, though the former are in a
very decided minority. This statement, however, applies to any and
all insect-eating birds. It would be just as reasonable to expect a
mower or reaper to cut grain and leave the weeds standing as to sup-
pose that from the hordes of insects around us birds will select only
the ones that are injurious to man and leave untouched those that are
beneficial. Then, too, a superabundance of any species of insects,
even beneficial ones, would be a nuisance. The service which swal-
lows render is to prey upon the whole insect tribe and so to reduce
the flood of insect life to a lower level where it may be more easily
dealt with by man.

CLIFF SWALLOW.

(Petrochelidon lunifrons.)

In the Eastern States the chff swallow has practically abandoned
its original nesting sites under cliffs, and new nests under the eaves
of houses and other buildings. The -writer has counted 80 nests
beneath the eaves of 1 barn. In California the bird has taken up
with the new order of things to some extent, but has not entirely
abandoned its old habits. It is a migrant and remains in the State
for about six months only during the breeding season, which is the
time when the bird does the most good.

The following discussion of the food of the cliff swallow is based
upon the examination of 123 stomachs, representing every month
from April to September, inclusive.

Vegetable food —Vegetable food to the extent of 0.32 of 1 percent
was found. In most cases this was simply rubbish taken acciden-
tally, though it includes a few small seeds.

Animal food —Of the animal matter the largest item is: Hymenop-
tera. These insects formed over 39 percent of the total food; most
of them were bees and wasps, and small parasitic species were i1denti-
fied in a number of stomachs; a few were ants. Unfortunately,
Inany parasitic insects are eaten by birds that take their prey upon
the wing, such as swallows and flycatchers. The fact is to be
deplored, but in most cases the percentage is not large. Perhaps the
most interesting insect among Hymenoptera eaten is the common
honey-bee (Apis mellifera). Of these, 34 were identified, all con-
tained in 11 stomachs, in one of which were 8 individuals. All were
drones—that is, males. Not a trace of a worker bee was found. In
two stomachs drones constituted the whole food and in several others
the principal part. It is probable that most of them were taken
when the queen made her marriage flight. So far as the writer has

;

SWALLOWS. 29

been informed, bee keepers do not regard the destruction of drones as
injurious to the swarm. In most cases drones are superabundant
and instead of contributing to the food supply they are a drain upon
it, so that the destruction of some of the surplus males is a positive
benefit to the colony.

Hemiptera, or bugs, stand next to Hymenoptera in importance in
the food of the cliff swallow. They form a little less than 27 percent
of the whole diet, and are represented by eight families, namely,
assassin-bugs, leaf-bugs, squash-bug family, stink-bugs, shield-bugs,
tree-hoppers, leaf-hoppers, and jumping plant-lice.” All of these,
excepting the assassin-bugs, are injurious to plants, and some of them
are pests at all times. Of these, probably the leaf-hoppers (Jasside )
are the worst. They suck the juices of plants, particularly grasses,
which they infest by millions. They are said to have but few enemies,
of which birds are the most effective. It is probable that they are
saptured by swallows when just skimming over the surface of fields,
or are snatched from the tops of grass and weeds. They were found
in 27 stomachs.

Leaf-bugs (Capside) are a very large family of harmful insects,
which feed almost entirely upon plants. Some species of this family
are pests of the worst description. Leaf-bugs were contained in 43
stomachs. The other insects of this order are more or less harmful,
but were not eaten so extensively.

Beetles of all kinds aggregate a little less than 19 percent. Of
these, 2 percent were useful species, such as carabids and coceimellids.
The others belong to 12 different families, most of which are harmful,
some very much so. Among them were a number of aquatic species.
These were probably captured by the swallows when flying Just above
the surface of the water. The principal flights of beetles do not
occur during the day, but chiefly in early evening and at night.

Flies are eatensby cliff swallows to the extent of nearly 12 percent
of the food. Most of these are the species commonly known as
enats, but one stomach contained a large horsefly (Tabanide). The
gnats have a habit of swarming afternoons and evenings, when many
are probably snapped up by swallows.

The remains of dragon-flies, lace-winged flies, ephemerids, and
spiders make up the rest of the food, or a little more than 3 percent.
As spiders do not fly, it may be asked how they were captured by
the swallows. They probably were snatched from their webs or from
the tops of weeds as the birds passed. Swallows pick up substances
even from the ground, as is shown by the vegetable component of
their food, and by other facts to be given presently.

4 Plant-lice and scale-insects were not present, and this may be explained from
the fact that their lives are passed mostly in a wingless condition.

30 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.
FOOD OF YOUNG.

Among the stomachs examined were those of 22 nestlings, varying
in age from 2 days to those just ready to leave the nest. They were
taken from May 30 to July 2, inclusive. In order to ascertain if 1m-
portant differences exist between the food of the adults and that of the
young, the contents of these stomachs were tabulated separately.
Comparison shows little or no difference in the quantity of vegetable
matter eaten by adults and young.

The animal matter in the food of the young is precisely of the
same kind as eaten by adults, but the proportions are rather difter-
ent. Hymenoptera are the largest item in the food of the young
as well as of the parent birds, and amount to 42 percent for
the former against 39 percent for the latter. Diptera stand next in
importance, with 30 percent for the young against 12 percent for the
adults. As these insects are mostly soft-bodied, it is the usual custom
of birds to feed a greater proportion of them to the young.. Hemip-
tera amount to a little more than 16 percent of the nestlings’ food,
while the adults eat them to the extent of nearly 27 percent. Beetles
are fed to the young to the amount of about 10 percent, while the
parents eat them to the extent of 19 percent. This again might
naturally be expected, as most beetles are hard and less easily
digested than flies and some other insects, and hence are less suitable
food for young birds.

From the foregoing it is evident that the food of young cliff
swallows does not differ in kind from that of the adults, but is dis-
tributed among the various orders of insects in somewhat different
proportions. Hymenoptera and Diptera constitute nearly three-
fourths of the diet, evidently because they are soft and easily broken
up and digested. Beetles and bugs appear in the stomachs less
frequently. While beetles are not extensively eaten, it is worthy of
note that the variety is considerable, as representatives of no fewer
than 10 species were contained in the stomach of one nestling. One
stomach held a few bits of eggshell, and gravel was identified in
two others. One of these contained 7 good sized gravel stones; the
other, pieces of glass and gravel. The supposed function of gravel
in the stomachs of birds is to assist in breaking up the food. That
eravel should be given young cliff swallows when not taken by the
adults is remarkable. The feeding of gravel to the young has been
noted in the case of other species of swallows.

WESTERN BARN SWALLOW.

(Hirundo erythrogastra.)

The barn swallow is rapidly learning, not only that the structures
built by man afford excellent nesting sites, but that the presence of

es 2

SWALLOWS. on

man is a sufficient protection against enemies. This species is gen-
erally distributed over the west coast region, but it is not so common
as it is in the East, probably because of the relative scarcity of nest-
ing sites. It is not improbable, however, that the end of the present
half century will see the barn swallow as common throughout the
whole of the region as it is in the East.

Kighty-two stomachs of barn swallows were examined, taken from
April to October, inclusive, though April was represented by only
two stomachs and October by one. While a greater number would
have been desirable, the close resemblance of the food to that of
the eastern birds, as shown by the contents of these stomachs, gives
assurance that the results are reasonably reliable.

Vegetable food—Practically no vegetable food was found in the
stomachs examined. A single unknown seed was contained in a stom-
ach taken in September.

Insect food—So far as these 82 stomachs show, the western barn
swallow subsists entirely upon insects, and it may be added that the
same is true of the eastern bird.

The largest item of food is made up of Hemiptera of various
families, amounting to nearly 39 percent of the whole. None of these
insects was present in the two stomachs taken in April, but in every
other month they constitute a large percentage of the stomach con-
tents, and in September, when 38 stomachs were taken, they amount
to 90 percent of the food for that month. Representatives of 8 fami-
lies were identified, but the principal and most important ones are
the leaf-bugs (Capside), which were found in 44 stomachs.

I lies are next in importance, and amount to 32 percent of the food.
Most of them belong to the family of the common house fly (Mus-
cide), though probably there were others too badly mangled to be
identified. No long-legged crane-flies (Tipulide), usually commonly
eaten by birds, were found.

Hymenoptera -constitute 18 percent of the food. Most of them
consist of wasps and wild bees, but a few stomachs contained ants.
One stomach had a drone honey-bée. Several birds had eaten para-
sitic species of Hymenoptera; a separate account was kept of these
so far as possible, but the total amount summed up to only about one-
fourth of 1 percent of the whole food.

Beetles aggregate nearly 10 percent of the whole, and belong to 13
families, with no preference for any. The bird probably snatches
any and all beetles which it comes across. A few of the destructive
engraver beetles (Scolytide) were found in 3 stomachs. Dragon-
flies and several unidentified remains constitute the remainder of the
food and amount to a little more than 1 percent.

32 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.
FOOD OF YOUNG.

The stomachs of two broods of nestlings of 4 each are included in
the foregoing. The contents do not differ from those of adults ex-
cept that they include a small percentage of gravel. Some of them
contained also fragments of eggshell; one had a piece of mother-of-
pearl (nacre), and one a small splinter of bone. It is curious that
these indigestible substances should be so often fed to nestlings when
the parent birds seldom take them.

VIOLET-GREEN SWALLOW.

(Tachycineta thalassina lepida.)

The violet-green swallow does not occur east of the Great Plains.
Its general habits appear to be almost identical with those of its east-
ern relative, the white-bellied swallow. |

The natural nesting site of both species was a hollow in a tree, and
the western bird still adheres to the original habit and nests in the
hollows of oaks and other trees, but the white-belly has to a great ex-
tent followed the example of so many of its relatives, and has taken
to holes in buildings or to boxes put up for avian use.

In its food habits the violet-green exhibits no marked peculiarities ;
in fact it may be said that the food of the different species of swal-
lows differs in degree rather than in kind. Stomachs of the violet-
green have been collected in every month, except June, from March to
September, inclusive, but only 7 were taken earlier than July. In
that month, however, and the two following months 67 were obtained,
a sufficient number to give a fair idea of the food at this season.

Insect food.—Insects constituted practically the entire contents of
these stomachs. No spiders were found, and the only vegetable mat-
ter was a single seed, no doubt accidental.

As with the barn swallow, the largest item is Hemiptera, or bugs.
These are represented by 10 different families, of which the leaf-
hoppers (Jassidx) were the most numerous, and the leaf-bugs (Cap-
side) next. Altogether they amount to 36 percent of the food.

Diptera stand next in importance, and in this respect also the violet-
green resembles the barn swallow. They constitute nearly 29 percent
of the food. Neither Diptera nor Hemiptera, however, are eaten
as freely by the violet-green as by the barn swallow, and the defi-
ciency is made up by Hymenoptera.

Hymenoptera amount to 28 percent of the food, and in the
month of July were mostly made up of ants. Six stomachs taken
on the same day and in the same locality were entirely filled with
these insects. One taken at the same place on the following day
was half filled with them, and this, with the exception of 1 percent

4
a

CALIFORNIA SHRIKE. ao

contained in one stomach in August, is the whole story of ants in
the food of the violet-green. All of the other hymenopterous food
consists of wasps and wild bees. In explanation of the fact that
this bird eats ants freely for a short time and then eats no more,
it may be stated that much of the time they are not obtainable.
It is only when the insects are on the wing while swarming that the
swallows can catch them, and then, being very numerous, they are
eaten freely.

Beetles collectively amount to something over 11 percent of the
food of the violet-green. Of these nearly 3 percent are Carabidee,
with a few coccinellids and carrion beetles, which must be reckoned
as useful insects. The rest, over 8 percent, are of several families,
all of which are more or less harmful. Three stomachs, collected
at the same time in Carmel Valley, are of interest. They contained
respectively 42, 45, and 40 percent of scolytid or engraver-beetles.
This was in the region of the Monterey pine (Pinus radiata), and
there is no doubt that these insects prey upon those trees, and
probably were taken when migrating in a swarm to fresh foraging
erounds. A few moths, with some unidentified insects, make up
the remainder of the animal food, a little more than 1 percent.

CALIFORNIA SHRIKE.
(Lanius ludovicianus ganmbeli. )

The California shrike is common in parts of the Pacific coast
region. At the present time fence posts and telegraph lines are the
vantage points from which shrikes ordinarily scan the ground for
prey, and in certain parts of the valley region it 1s unusual to glance
along a line of wire and not see one or more within a short distance.
It does not seem that trees and shrubs could ever have adequately
supphed the need for lookout stations which is now filled by the poles
and wires.

There seems to be a mysterious sympathy between the shrike and
the little sparrow hawk, or perhaps their relations are inspired by
jealousy. The sparrow hawk also occupies the poles and wires as a
lookout for prey, and whenever a hawk stations himself upon one of
the poles, there, at no great distance, is sure to be a shrike keeping
close watch upon the movements of the larger bird. When the latter
moves the shrike follows, and seems to aim to keep the other continu-
ally in view. Perhaps the shrike sees in the hawk a rival and con-
siders that his preserves are being trespassed upon, though one would
think there was room enough and prey enough for both. No case of
actual conflict between the two has been observed—only this constant
and unremitting surveillance on the part of the shrike.

9379—No. 30—O07

»
3]

34 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

The shrike resembles a bird of prey in form of beak and, to a cer-
tain extent, in food habits. Unlike the true birds of prey, however, its
feet are not provided with talons for seizing prey and holding it
securely while it is being torn into pieces. Whenever the shrike cap-
tures game that must be torn apart it presses it firmly down into a
forked branch where it can readily be dissected.

The habit of the shrike of storing food apparently for future con-
‘sumption has often been noticed. When food is abundant surplus
‘aptures are hung on thorns, sharp twigs, or, in recent times, the
barbs of wire fences until needed; but as such occasions seldom arise,
nine-tenths of this stored food is wasted so far as the shrike is
concerned. Various more or less plausible explanations of this
habit have been offered, but the simplest and most natural seems to
be that much of the time the bird hunts simply for the pleasure and
excitement of the chase, and as prey is often captured when hunger
has already been satisfied it is stored for future use. It is the same
instinct and lust for slaughter that prompts man to kill game that
he can not use. The habit seems to be manifested also in a somewhat
different way by the crow and magpie, which store up bits of glass
or bright metal for which they can have no possible use. In the
‘ase of the shrike, however, the habit is useful to man if not to
the bird, for most of its prey consists of noxious creatures, the de-
struction of which is a decided benefit.

The diet of the shrike and that of the sparrow hawk are almost
exactly alike. It is a curious illustration of two species standing
far apart systematically but by special modification approaching
each other in food habits. The sparrow hawk has all the equipment
of a carnivorous bird, but owing to its diminutive size its attacks:
are necessarily confined to the smaller kinds of prey, largely insects.
The shrike, on the other hand, is a member of a group almost
purely insectivorous, but it is so large and strong and has a beak
so modified that in addition to its ordinary diet of insects, it is able
on occasions to capture and tear apart small birds and mammals.
While at present the two birds subsist upon much the same diet it
is evident that their food habits have been modified in different
ways. The natural food of the hawk family as a whole is vertebrate
animals, to which some of its members, including our little sparrow
hawk, have added a large percentage of insects. The normal food
of the shrike is insects, to which on occasions it adds the sntaller
species of vertebrates.

Like the birds of prey and some other birds, the shrike habitually
disgorges the indigestible portions of its food after the nutritive part
has been digested. The bones and hair of mice are rolled into com-
pact pellets in the stomach and finally disgorged. From examination
of these a very good idea of the shrike’s food may be gained.

Z ‘

)

—_*” an, “oe

CALIFORNIA SHRIKE. 35

A shrike of the eastern subspecies was kept in confinement for some
weeks by the Biological Survey and notes made in regard to its food
habits. A thorny bush was placed in the cage, and whenever the
bird was given food in excess of its immediate wants it impaled the
surplus upon a thorn, taking great pains to press it securely down.
On one occasion a dead mouse was placed in the cage; it was at once
seized and forced into the fork of the bush and was then torn piece-
meal and eaten. Note was taken of the time when the last bit was
swallowed, and a close watch kept for further results. In an hour
and a half the bones and hair of the mouse were disgorged in the form
of a neat pellet. Everything digestible had been stripped from the
bones. A May-beetle (Lachnosterna) was eaten and the pellet con-
taining the remains appeared in an hour and twenty minutes. At
another time a ground beetle (Calosoma) and a stink bug (Nezara)
were eaten and their remains appeared in forty minutes. <As both
of the insects are nauseous, at least to human smell and taste, it
is possible that they may have been unacceptable to the stomach of
the bird, and so were rejected before digestion was complete. On
another occasion a second Calosoma and a moth were given, and their
remains were regurgitated in an hour and fifteen minutes. These
experiments show how rapid is the process of avian digestion.

In the investigation of the food of the California shrike 124 stom-
achs were examined. They were collected in every month, but the
greater number were taken in the warmer months.

Vegetable food —Animal food of all kinds amounts to 97.5 percent,
or so nearly the whole that it is fair to suppose that the greater
part of the 2.5 percent of vegetable matter present was swallowed
unintentionally—that is, when sticking to something else. All of it

yas contained in 9 stomachs. Fruit appeared in 2 stomachs, seeds in

2, and rubbish in 6. Of these probably only the fruit was taken as
food. One stomach was filled with elderberries to the amount of 84
percent of the contents, the other with the seeds of blackberries or
raspberries to the extent of 13 percent. It thus appears that the
shrike sometimes eats fruit.

Animal food—The animal portion of the shrike’s food may be
divided into three parts: Insects, 83 percent; spiders and a few snails,
etc., 2 percent; vertebrates, 12 percent.

Insect food.—In comparing the food of eastern subspecies of
shrike and the one under discussion, we find that more insects are
eaten by the western one. The figures for the eastern bird are:
Insects, 68 percent; spiders, 4 percent; vertebrates, 28 percent. The
difference is undoubtedly due to climate, the western bird being
able to find insects all the year round, while the eastern one discovers
very few during the winter. Insects probably are always preferred

- when obtainable.

36 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

Of insects eaten by the shrike, the largest item is Orthoptera—
that is, grasshoppers and crickets—which amount to nearly 43 percent
of the whole food. They are eaten in every month of the year, and
in August and September reach nearly 70 percent. These are the
normal grasshopper months, the ones in which Eastern birds enjoy
their annual grasshopper feast. Ordinary grasshoppers form the
greater part of this item of food, but a good many crickets are eaten,
especially the brown and striped so-called wood crickets. One group
of these is particularly noticeable—a group of large soft-bodied mon-
sters of the genus Stenopelmatus, many of which live under dead
leaves, stones, and rubbish, and do not often voluntarily show them-
selves by the hight of day. It seems strange that the shrike, a lover
of open and sunshine, manages to discover these creatures. They are
sometimes called ‘ sand-crickets, and perhaps at times come out into
the open, but the writer has never seen one except when dug from
under rubbish. It is not known whether these insects are harmful or
beneficial, so the shrike’s consumption of them has no economic inter-
est. It is quite the contrary, however, with regard to grasshoppers,
for they are harmful in all stages of existence, and the shrike is
directly beneficial to the farmer to the extent that it destroys them.

Beetles collectively are second in importance in the shrike’s diet.
They amount to 16 percent of the food, but of this about 7 percent
are the useful ground beetles (Carabide) and carrion beetles (Sil-
phide). The rest are mostly harmful. The presence of these last
is a curious point in this connection. These insects are probably use-
ful, and while no great number of them are consumed, it seems rather
strange that they are eaten at all. The surroundings of these beetles
are not pleasant, and they do not generally serve as food for birds
except crows and other garbage hunters. Is it possible that the
shrike finds them on the game which it has hung on twigs or thorns?
They were noted in 8 of the 124 stomachs, and three species were iden-
tified. Most of the beetles eaten by the shrike are of the larger spe-
cies, but 1t does not disdain small game, and quite a number of small
leaf-beetles and weevils were among the others.

Ants and wasps amount to something more than 11 percent in the
diet of the shrike. Naturally they are mostly eaten in the warmer
months, and the wasps far outnumber the ants.

Moths and caterpillars are taken to the extent of somewhat more
than 7 percent, and seem to be a regular though small component of
the food. Unlike the wasps, the greater number of these were eaten
in the colder months. One stomach was entirely filled with the re-
mains of 15 moths, a most unusual occurrence, for adult Lepidoptera
do not form a large element of the food of any bird yet investigated.

3ugs and flies are eaten occasionally. The stomachs taken in Feb-
ruary contained a good percentage of Hemiptera, and so did those

CALIFORNIA SHRIKE. 837

collected in July. In one stomach remains of robber-flies ( Asilide )
were detected. This isa family of large predaceous flies, some species
of which are said to prey upon honey-bees. These two orders and a
few other odd insects constituted 5 percent of the food.

Spiders and several other kindred creatures form less than 2 per-
cent of the food, but though not eaten in great numbers they appear
in a good many stomachs. In one stomach was found one of those
bristly and uncanny monstrosities of the order of jointed spiders
(Solpugida). It is wonderful that any bird should attack one, still
more that it should eat it, as it would seem to be about as palatable
as a paper of pins. The lingual ribbon, or tongue, of a snail was
found in one stomach, and bits of what appeared to be the limbs of
small crustaceans in several. They did not amount to a noticeable
percentage.

Vertebrates.—The vertebrate part of the shrike’s food amounts to
a little more than 12 percent, and consists of the remains of small
mammals, birds, and lizards. Mammals were found in 4 stomachs,
birds in 2, and lizards in 12. Neither of the birds could be identified
further than that both were small song birds. Of the mammals,
one was a pocket mouse (Perognathus), one a young field mouse
(Microtus), and one a shrew (Sorex). The fourth mammal could
not be identified, as there was little left except hair. The lizards
were not recognizable either generically or specifically, as the remains
consisted only of bones and scales. From an economic standpoint,
lizards are useful animals, as they subsist on insects. The same is
true of birds, so that in destroying birds and lizards the shrike is
doing harm. Fortunately, it does not eat many birds. The destruc-
tion of the mammals is an unmixed blessing, except, perhaps, in the
case of the shrew (Sorex), which is largely insectivorous. Even if
all the above vertebrates were useful the score against the shrike
would not be a very heavy one and would not outweigh the
value of its services in destroying grasshoppers. In the writer’s field
experience with the shrike only one attempt to capture a vertebrate
animal was observed. In this case the shrike was seen to plunge
into a thicket of weeds in pursuit of a brood of tiny quail, but a
few seconds later it emerged in a great hurry, closely followed by
the irate cock quail. As a matter of fact, the noxious mammals
eaten both by the eastern and western shrikes far outnumber the
birds, and when to the former are added harmful insects the balance
is very largely on the credit side.

FOOD OF YOUNG.

No nestlings of shrikes were at hand for investigation, but the
stomachs of two young just out of the nest were examined. Both

38 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

were filled with beetles, ants, wasps, and crickets. In a bird so
thoroughly insectivorous as the shrike it is not probable that the food
of the nestlings differs essentially from that of adults.

As a feature of the landscape and as lending animation to rural
scenes the shrike in California is a pronounced success, and when one
sees him jauntily balancing on a telephone wire it is pleasant to
reflect that in his economic relations he is as admirable as he is from
the esthetic point of view.

VIREOS.

The vireos are a group of rather small tree-haunting birds of plain
colors, modest habits, and sweet but unobtrusive voices. One or the
other of the several species inhabits pretty much everything in the
way of a tree from the monarchs of the forest down to the humblest
underbrush. In thickly settled country vireos inhabit gardens,
orchards, and city parks, and shade trees along the village streets.
Most of them are migrants, and leave the United States in winter,
but a few remain on the Pacific coast throughout the year. Their
food consists largely of insects, though a little fruit and some seeds
are occasionally eaten.

In the insect diet of the vireos there is one element which consti-
tutes a bar sinister on an otherwise brillant escutcheon. All the
species investigated show a decided taste for ladybirds—that 1s,
coccinellid beetles. No other genus of birds, nor any single species
(with one possible exception), so far has been known to manifest
such fondness for these useful insects. In California the destruction
of ladybird beetles is perhaps a greater crime than it would be in
almost any other section of the country, for here the bark scales and
plant-lice upon which these beetles feed are very destructive, and
every device for their extermination has been employed, even to
importing several foreign species of these predatory beetles.

Time was when the devastation of the San Jose scale and several ~
other species of scale insects threatened the fruit industry of Cah-
fornia, and there can be no reasonable doubt that the coecimellid
beetles of both the imported and native species were largely instru-
mental in checking the spread of these pests. It is to be remarked
that these beetles are wonderfully abundant in California, probably
more so than any other family. The writer found them upon corn,
weeds, grass, and bushes, often where apparently there was none
of their natural food. In mitigation of the vireos’ habit of eating
ladybirds all that can be said is that where there is such a super-
abundance of the insects the damage is minimized.

The writer is glad to be able to add that besides the coecinellids,
vireos eat many harmful insects, among which are the black olive

VIREOS. 39
seale. Here, then, is an instance where the bird eats the useful beetle
and also its noxious prey. As there is nothing to indicate that the
bird exercises a choice between them, we must infer that it eats both
whenever it finds them. It eats the beetles and the food (scales)
upon which they feed. From this point of view also it must be
allowed that the harm done by the vireos in eating coccinellids is offset
to some extent.

WESTERN WARBLING VIREO.
(Vireo giltus sivainsoni, )

One hundred and ten stomachs of the warbling vireo have been
examined. They were collected during the seven months from April
to October, inclusive, and though hardly as many as could be desired,
they probably furnish a fair idea of the food during that portion of
the year.

Vegetable food.—Insects, with a few spiders, amount to over 97
percent of the cet, leaving less than 3 percent of vegetable matter,
practically all of which was taken in August and September; it
consisted of wild fruit (elderberries), a few seeds of poison oak, a few
other seeds, and some rubbish. _

Animal food —Of the animal food the largest item is Lepidoptera ;
that is, caterpillars, moths, and the hke. These amount to something
more than 43 percent of the whole. Caterpillars make up the great
bulk of this portion of the food and are a very constant and regular
article of diet. Fewer are eaten in July and August and more at the
beginning and end of the season. In April they amount to over 82
percent of the food of the month. Pup of codling moths were iden-
tified in four stomachs, and minute fragments probably of the same
were found in several others. A few adult moths also were found,
but the species could not be identified.

Hemiptera are the next most important item of diet, and amount
to 21 percent. They consist of stink-bugs, leaf-bugs, leaf-hoppers,
spittle-insects, tree-hoppers, and scales. The last were the black olive
species (Saissetia olew). Coccinellid beetles, or ladybirds, were eaten
to the extent of over 19 percent of the whole. None was in the
stomachs taken in October, while the greater part (over 63 percent)
was contained in those obtained in July. The species belong to the
genera Hippodamia and Coccinella, which are larger than those of
the genus Scymnus selected by the warblers. Other beetles, mostly
harmful species, amount to more than 7 percent.

Hymenoptera, which are an important food of the warblers, are
conspicuous by their absence in the stomach of the warbling vireo. A
little more than 1 percent represents the sum total. They consist of a
few ants and an occasional wasp.

40 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

A small number of flies, grasshoppers, and dragon-flies make up a
little more than 3 percent of the miscellaneous insects. Spiders were
eaten to somewhat less than 2 percent.

CASSIN VIREO.
(Vireo solitarius cassini.)

This is another of the tree foragers hving in summer in orchards,
canyons, and forests.

Its food consists of the same elements as that of the last-described
species, but in somewhat different proportions. Forty-six stomachs
were examined, taken in every month from April to November. They
afford at least a fair indication of the food for those months.

Vegetable food—The vegetable food, which was only a little more
than 2 percent of the total, was made up of leaf galls, seeds of poison
oak, and a few bits of rubbish. Not a trace of fruit was found.

Animal food—The animal matter amounts to nearly 98 percent of
the whole. Hemiptera are the largest item and amount to nearly 51
percent. The various families represented are those of the squash-
bugs, leaf-bugs, stink-bugs, shield-bugs, leaf-hoppers, tree-hoppers, the
jumping plant-lice, and scales. The latter are represented as usual by
the black olive scale, which was contained in four stomachs. Caterpil-
lars, with a few moths, are next in importance and form more than
23 percent of the whole food. They were eaten in every month and
are evidently a favorite diet.

Hymenoptera are eaten much more largely by this species than by
the last. They amount to over 7 percent, and are mostly wasps, with
a few ants. This record, however, is likely to be modified by further
investigation. |

Ladybird beetles were eaten to the extent of a little less than 6
percent, which is quite reasonable as compared with the record of the
warbling vireo. It is, however, much greater than that of any bird
outside the present genus, except the pygmy nuthatch, and in the
vase of that bird the evidence is too meager to be accepted at its face
value. Other beetles amount to a little more than 3 percent of the
food, and are mostly weevils and small leaf-beetles (Chrysomelide).
A few flies, grasshoppers, and other insects amount to somewhat more
than 2 percent, and these, with 4 percent of spiders, make up the
remainder of the animal food.

SUMMARY.
In glancing over this record of the Cassin vireo it appears that

bugs are the favorite food, as shown by the numbers consumed; but
vaterpillars, though second in quantity, are eaten with greater regu-

VIREOS. 4]

larity and appear in the food of every month. The consumption of
ladybirds is very moderate for a vireo, and on the whole the bird
probably does not do much harm in this way. All the other beetles
are harmful, as are most of the other insects which compose the bird’s
food.

HUTTON VIREO.

(Vireo huttoni.)

This species is a resident of most parts of California west of the
ereat interior valley. In food habits it does not differ remarkably
from the foregoing, but the various elements of its food are in
shehtly different proportions. |

Vegetable food —Examination of 54 stomachs shows that less than
2 percent is composed of miscellaneous articles of vegetable origin.
One stomach contained a few seeds of elderberries, two contained
those of poison oak, and these with a few galls and some rubbish
make up the whole of this part of the food. It would seem that with
most of the vireos vegetable matter is taken accidentally, or possibly
experimentally to see how it tastes, rather than as an approved article
of diet.

Animal food.—Of the 98 percent of animal food the largest item is
Hemiptera, as is the case with many of the vireos, titmice, and gnat-
catchers. These insects amount to 49 percent of the food of the pres-
ent species, and are represented by the following families: Assassin-
bugs, leaf-bugs, stink-bugs, leaf-hoppers, tree-hoppers, jumping
plant-lice, and bark scales. These last consist, as is so often the case,
of the black scale, which appeared in 8 stomachs. Caterpillars, with
a few moths and cocoons, are next 1n importance, and constitute over
22 percent of the food. These two items not only make up more than
two-thirds of the diet, but are eaten with great regularity through the
year and seem to be the staples of the bird’s food.

Beetles, collectively, amount to nearly 11 percent. Of these 8 per-
cent are ladybirds, somewhat more than were eaten by the Cassin
vireo, but only half of the amount eaten by the Swainson vireo. The
remaining beetles, less than 3 percent, were largely weevils, among
which a few engravers (Scolytide) could be distinguished. Hyme-
noptera, including both wasps and ants, form about 7 percent of the
food. Among them several parasitic ones were identified, but there
were not enough to be of any great economic interest. A few mis-
cellaneous and unidentified insects amount to nearly 5 percent of the
food. Flies and grasshoppers make up a part of this, but they are
only rarely eaten. Spiders are consumed regularly but sparingly.
They amount to a little more than 2 percent.

49 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

OTHER CALIFORNIA VIREOS.

Several other species and subspecies of vireos occur in California
| ] ’
but in the general character of their food they agree closely with the
foregoing.
BEETLES FOUND IN STOMACHS OF VIREOS.

Coccinella t. californica. Gastroidea viridula.
Hippodamia convergens. Blapstinus spp.
ScyMnus spp. Apion cribricollis.
Agrilus spp. Balaninus spp.
Crepidodera helxzines. Copturodes koebelei.
WARBLERS.

( Mniotiltide. )

The warblers, or more properly the wood warblers, to distinguish
them from the warblers of the Old World (Sylviide), are a large
family of rather small and often brightly colored birds. For the
most part they inhabit woods and shrubbery, and while some of them
obtain their food from the ground they seldom wander far from
trees and bushes. The species and subspecies are so widely dis-
tributed that, excepting the deserts, there are no very extensive areas
within the boundaries of the United States that do not have their
complement of these interesting birds. Their food consists largely
of insects, and they subsist upon species which frequent the leaves
and trunks of trees. Wasps and flies (Hymenoptera and Diptera)
form a large portion of their diet, and as these insects are the best
of fliers a considerable portion of them are taken on the wing. The
warblers probably eat more of these elusive insects than does any other
family of birds except the flycatchers (Tyrannidie) and the swallows.

Upward of 75 species and subspecies of warblers are known within
the limits of the United States, and a majority of these occur in the
West, though perhaps they are not so abundant individually as in
the Mississippi Valley and Appalachian region.

The genus Dendroica, as the one best exhibiting the characteristic
traits of the group, may be taken as the type of the family. There
are about 30 species and subspecies of the genus in this country, and
the ones whose food is discussed in the following pages occur in
California and on the Pacific coast generally.

In a résumé of the food of the warbler family one is impressed
with the general noxious character of the insects which compose it.
The order of Hemiptera, commonly called bugs, contains some of the
Worst insect pests that afflict mankind. Moreover, from their small
size and unobtrusive habits they are not eaten by many of the larger
birds and are difficult to exterminate by the devices of man. But
in some of their multiple forms they are preyed upon by the warblers

Pt:

ies

Bull. 30, Biological Survey, U. S. Dept. of Agriculture. PLATE III.

AUDUBON WARBLER (DENDROICA AUDUBONI).

| WARBLERS. 43

to an average extent of more than 25 pereent of the whole food.

~ Most of the other insect food, also, is either of a noxious or neutral
deseription, and the vegetable portion is so small that it may be dis-
regarded. There is probably no finer tribute to the beneficial char-
acter of these birds than that of Dr. Elhot Coues, who says:

With tireless industry do the Warblers befriend the human race; their uncon-
scious zeal plays due part in the nice adjustment of Nature’s forces, helping to
bring about the balance of vegetable and insect life, without which agriculture
would be in vain. They visit the orchard when the apple and pear, the peach.
plum, and cherry, are in bloom, seeming to revel carelessly amid the sweet-
scented and delicately-tinted blossoms, but never faltering in their good work.
They peer into the crevices of the bark, scrutinize each leaf, and explore the
very heart of the buds, to detect, drag forth, and destroy these tiny creatures,
singly insignificant. collectively a scourge, which prey upon the hopes of the
fruit-grower and which, if undisturbed, would bring his care to naught. Some
Warblers flit incessantly in the terminal foliage of the tallest trees; others hug
close to the scored trunks and gnarled boughs of the forest kings; some peep
from the thicket, the coppice, the impenetrable mantle of shrubbery that decks
tiny watercourses, playing at hide-and-seek with all comers; others more
humble still descend to the ground, where they glide with pretty, mincing steps
and affected turning of the head this way and that, their delicate flesh-tinted
feet just stirring the layer of withered leaves with which a past season carpeted
the ground.¢

Following is a list of insects, mostly beetles, identified in the stom-
achs of the warblers examined. A number of these had been eaten

by nearly every species:
COLEOPTERA.

Coccinella t. californica. Crepidodera helxrines.
Scunminus pallens. ’pitric parvula.

Sceymnus marginicollis. Bruchus pauperculus.
NCyMnus Sp. NOY. Blapstinus pulverulentus.
Microlipus laticeps. Notorus alameda.
Melanophthalma americana, Anthicus difficilis.
Aphodius_rugifrons. Diodyrhynchus byturoides.
Diachus auratus. — Apion vespertinum.,
CGastroidea cyanea. Onychobaris insidiosa.
Diabrotica soror. Falaninus sp.

HEMIPTERA.
Naissetia ole. ; Aspidiotus rapax.
AUDUBON WARBLER.
(Dendroica auduboni.)
(Plate III.)
The Audubon warbler is well distributed over the Pacific coast

region, breeding in the mountains and descending in winter to the
valleys and plains of California. It is one of the most abundant

: a Birds of the Colorado Valley, p. 201.

44 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

species, and may be considered as typical of the genus, especially in
the matter of food. In the winter season it is a frequenter of
orchards, gardens, and dooryards where it pursues its business of
insect hunting with a persistent assiduity worthy of all praise. <At
this season it 1s very familiar and easily approached.

In investigating the food of the Audubon warbler 383 stomachs
have been examined. They were taken from July to May inclusive.
Geographically they are distributed from the San Francisco Bay
region southward to San Bernardino, and probably give a fair idea
of the winter diet of this bird in California. The food consisted of
nearly 85 percent of animal matter (insects and spiders) and a little
more than 15 percent of vegetable.

Animal food.—The largest item of animal food is Hymenoptera—
wasps and ants—which aggregate a little more than 26 percent of the
whole. By far the greater number of these are ants, and as plant-
lice also are eaten to a considerable extent, it is probable that many
of the ants are species that take care of the lice. The other members
of this order are mostly rapid fliers, so the inference is that they were
caught on the wing. The greater number were eaten in the fall and
spring months. In our record May appears as the month of least
consumption—6 percent. August is the month of greatest consump-
tion—61 percent. This record, however, probably is unreliable, as
but one stomach was taken in this month. A few were identified as
belonging to parasitic species.

Flies (Diptera) are represented in the stomachs of the Audubon
warbler to the extent of a little more than 16 percent, or one-sixth of
the whole food. This is one of the largest, if not the very largest,
record of this order of insects eaten by any bird except some of the
swallows. Even the so-called flycatchers do not eat so many flies as
this warbler—in fact, the name ‘ wasp-catchers > would be much more
appropriate for that family. The flies eaten by the Audubon war-
bler must have been caught in mid-air, for flies as a rule do not allow
themselves to be captured without at least attempting to escape.
These insects are so soft-bodied that it is not often possible to deter-
mine more about them than that they are Diptera. Two families
were identified—Muscide, the family of the common house fly, and
Tipulide, or crane-flies, the long-legged mosquito-like creatures other-
wise known as “ daddy-long-legs.” Most of the Diptera, however,
are the smaller species, such as gnats, which fly in swarms, and being
rather sluggish are more easily captured. They are eaten with
remarkable regularity during the whole season, with no decided de-
crease in the winter months—in fact, more were eaten in January
than in either September or April. March is the month of maximum
consumption, when Diptera constitute over 54 per cent of the whole

food.

WARBLERS. 45

Bugs collectively amount to nearly 20 percent, of which a little
more than 4 percent are scales and plant-lice. The black olive scale
(Saissetia olew) and another species (Aspidiotus rapax) were found
in 15 stomachs. Plant-lice (Aphidide) were contained in 39 stom-
achs, and from the numbers eaten appear to be favorite food. Sevy-
eral stomachs were entirely filled with them, and the stomachs in
which they were found contained an average of 71 percent in each.
~The remainder of the hemipterous food, more than 15 percent, 1

made up of stink bugs, leaf-hoppers, and tree-hoppers, with a con-
siderable residue of other remains not further identified. Bugs, as a
whole, are eaten rather irregularly, and the greater number are eaten
in the fall months, after which the number consumed gradually
decreases. Caterpillars are eaten rather regularly by the Audubon
warbler, but not in great numbers. They amount to nearly 14 percent
of the food of the season, though this figure includes a few moths and
chrysalids. Some cocoons of tineid moths were in several stomachs.

Beetles of all kinds aggregate something more than 6 percent of
the whole diet. They belong to several famihes, but the snout-beetles
are most prominent. The others belong to about a dozen families,
and, except a few carrion and ladybird beetles, are injurious. A few
insects other than the above and some spiders, in all a little less than
2 percent, make up the rest of the animal food.

Vegetable food—tThe vegetable food of the Audubon warbler con-
sists of fruit, weed seed, and a few miscellaneous substances. As the
bird does not visit the fruit-growing regions during the fruit season,
it is not chargeable with injury to cultivated crops. Almost all the
fruit eaten is wild and of no value, though in the fall it probably
feeds to some extent upon various belated products of the orchard.
The total of fruit for the season is less than 5 percent, of which the
greater amount is eaten in the autumn and early winter, after which
the quantity is unimportant.

The most prominent item of vegetable diet, however, is weed seed.
This is eaten to the extent of a little more than 9 percent of the whole
food, and is taken in almost every month of the bird’s stay. the
greater quantity in winter. Something more than 31 percent was
eaten in December, 22 in January, and 31 in February, after which
it decreases regularly to April. One of the most important seeds
eaten by the Audubon. warbler is that of the poison oak (hus diver-
siloba (Pl. II, fig. 9). In most cases the whole seed is not eaten by
this bird, but only the waxy outer coating, which is easily identified by
certain woody granules which it contains; hence the bird does not aid
in the distribution of these noxious plants. The remaining vegetable
food, amounting to less than 2 percent, consists principally of rubbish.

46 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

SUMMARY.

It must be evident to the most casual reader that this bird is a

valuable asset in the orchard and garden. The great bulk of its
food, both animal and vegetable, is composed of elements the elimina-
tion of which from the farm is a benefit. As has been elsewhere
pointed out, the destruction of insects during winter or in early
spring is more useful than in the height of the midsummer abun-
dance, for in spring the progenitors of the season’s broods are
destroyed and with them the possibility of thousands of progeny.

MYRTLE WARBLER.
(Dendroica coronata. )

This is another winter visitant in California. Only 10 stomachs
of this species have been examined, but the contents show the pre-
dominant food characteristic of the genus. There is one point, how-
ever, which is worthy of passing note. One of, these stomachs was
completely filled with greedy scales (lspidiotus rapax), with the
exception of a small fragment of a beetle; another contained remains
of the black olive scale, and still another some scales not identified.

TOWNSEND WARBLER.
(Dendroica townsend. )

The Townsend warbler, like the Audubon, summers in California
only in the mountains. During the migration and in winter it visits
the valleys. Like other members of the - oie, it is an Imsect eater
almost exclusively, and does not eat fruit or other farm products.
Thirty-one stomachs were taken in the four ar from October to
January inclusive, in the region from Pacific Grove to Watsonville.

As our stomach examinations disclose the fact that the food of this
warbler agrees closely with that of cthers of the same group, a fair
idea of the diet for the above months is obtained.

Animal food—The animal food consists of insects and a few
spiders, and amounts to over 95 percent of the food during the time
specified. Of this, bugs make up 42 percent, mostly stink-bugs
(Pentatomida) and ‘a few leaf-hoppers and scales. The former
appear to be a favorite food. Although these insects are eaten with
considerable regularity by most of the warblers of this group, they
are not usually taken in great numbers, but the ‘Townsend warbler
eats many, and several stomachs were entirely filled with them.

Hymenoptera, consisting of both wasps and ants, are eaten to the
extent of 25 percent of the food. Most of them are winged species.
Perhaps the most striking point in the food of this bird is the great

WARBLERS. 47

number of weevils or snout-beetles represented. They amount to over
20 percent of the food, while all other beetles form less than 1 percent.
The greater number of these insects were of the species Diodyrhyn-
chus byturoides, a weevil which destroys the staminate blossoms of
coniferous trees. Five stomachs contained, respectively, 68, 65, 53,
50, and 35 of these beetles, or 271 in all. Moreover, each of these
stomachs contained fragments which could not be satisfactorily iden-
tified; probably these were the same species, so that the total con-
tained in the 5 stomachs is probably nearer 300. Several other
stomachs contained fewer of these weevils. Representatives also of
another family of snout-beetles very destructive to timber were pres-
ent in a few stomachs. These were the engravers (Scolytide), which
lay their eggs beneath the bark of trees, where they hatch, and the
larve bore in every direction. Caterpillars and a few miscellaneous
insects and some spiders make up the remainder of the animal food.

_ Vegetable food.—The vegetable matter, which amounts to less than
5 percent of the whole, consists of a few seeds and leaf galls. As the
galls in most cases contained small larve it is a question if they
should not be reckoned as animal food. .

SUMMARY.

While this can be considered as only a preliminary study of the
food of the Townsend warbler, the thoughtful reader can not fail to
be impressed by the fact that this bird exhibits some very valuable
economic traits, especially in its relation to the forest. The stomachs
containing the pine-eating weevils were from birds killed in the pine
forests of Pacific Grove, near Monterey, as also were those containing
the engraver beetles. Of the 30 stomachs examined, 19 held the
remains of weevils, from which it would appear that these insects
are preferred as an article of food. As this group of beetles con-
tains some of the worst pests of the forest and orchard, any bird that
eats them so freely must be considered as performing a most welcome
service.

SUMMER WARBLER.

(Dendroica wstiva subspp. )

The summer warbler, yellow warbler, or summer yellowbird, as it
is variously called, is represented in the West by two subspecies, one
of which visits California only as a migrant. The other, which does
not differ essentially from the eastern form, is a rather common sum-
mer resident throughout the valley and foothill regions. In the Fast
this bird is fairly domestic in its habits, and may often be seen about
gardens and orchards, or in rose bushes nearer the house. In Cali-
fornia jt is not quite so familiar, but is becoming so and probably will

48 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

soon acquire the habits of its eastern relative. From the material at
hand this warbler appears to be even more exclusively insectivorous
than the species last discussed. This may arise from the fact that
it stays in the fruit districts during summer, when insects are most
numerous; but it must be remembered that this is also the season
when fruit and vegetable food generally are most abundant.

William Prond, of Chico, Butte County, thus recounts the efficient
service of this and other warblers:

On Rancho Chico is a fine collection of roses, all of which are more or less
liable to attacks from Aphis rosea, but are perfectly free from other insects.
I attribute this to the protection of small birds, among the most active of which
are Dendroica estiva, * * * Helminthophila celata, Regulus calendula.

The following statements in regard to the food of the summer
warbler are based on the examination of 98 stomachs, all collected
from April to October, inclusive. |

Animal food—The animal food, composed entirely of .insects and
a few spiders, amounts to over 97 percent. The largest item is
Hymenoptera, which amounts to over 30 percent, about half of which
are ants. The remainder are small bees and wasps, some of which
are probably parasitic species, though none were positively identi-
fied. The insects of this order must be favorite food, as they are
eaten with remarkable regularity and constitute an important per-
centage of the diet in every month represented. Caterpillars, with a
few moths, aggregate over 18 percent. The greater number are
eaten in spring and early summer, but in fall they give place to other
insects.

Beetles form nearly 16 percent of the diet, and embrace about a
dozen families, of which the only useful one is that of the ladybirds
(Coccinellide), which are eaten to a small extent. The great bulk
of the beetle food consists of small leaf-beetles (Chrysomelide), with
some weevils, and several others. One stomach contained the remains
of 52 specimens of Votoxus alameda, a small beetle living on trees.
Bugs (Hemiptera) constitute over 19 percent of the food, and are
eaten regularly every month. Most of them consist of leaf-hoppers
(Jasside) and other active forms, but the black olive scale appeared
in a number of stomachs. Plant-lice were not positively identified,
but some stomachs contained a pasty mass, which was probably made
up of these insects in an advanced stage of digestion.

Flies seem to be acceptable to the summer warbler; they are eaten
to the extent of nearly 9 percent. Some of them are of the family
of the house fly, others are long-legged tipulids, but the greater num-
ber were the smaller species commonly known as gnats. A few
small soft-bodied Orthoptera (tree-crickets), a dragon-fly, and a few
remains not identified, in all about 5 percent, made up the rest of
the animal food.

WARBLERS. 49

Vegetable food—Yhe vegetable portion is only about 24 percent.
Nearly all of this was fruit pulp contained in a single stomach.
This, with one or two seeds and a few accidental bits of rubbish,
makes up the whole vegetable contingent, which, therefore, may be dis-
missed without further comment.

FOOD OF NESTLINGS.

Some idea of the amount of insect food eaten by warblers may be
obtained by watching the feeding of their young by the parent birds.
A nest of the summer warbler containing two young, about a week
old when discovered, was watched for six hours distributed over three
days. The nest was situated in a prune tree in an orchard, and it is
practically certain that all the food for this family was obtained in
the orchard. The results of the observation appear in the following
table:

Forenoon. Afternoon.

vation | of feed- | "vation of feed-

; | ings. | ; ings.

JUNC LID 1 eres apne eel oe. ota vars | - 3. 26-4. 26 21
June 14 8.21- 9.21 SF) Sera eteterh ks eal he eee

June 14 10. 34-11-34 32 4. 36-5. 36 | 31

June 15 8.00- 9.00 36 | 1. 11-2. 11 30

In six hours 181 feedings were observed, an average of 30% per
hour. As there were only two young, it follows that each nestling
was fed 15 times per hour, or for a day of fourteen hours 210 times.
Both parent birds took part in feeding the young, but it was noted
that the female visited the nest most frequently.

SUMMARY.

From the above facts it is evident that the presence of a few
warbler nests in an orchard goes far to safeguard the trees from
attacks of insect enemies. The inference is plain that the presence
of insectivorous birds should be encouraged by the orchardist by
every means in his power. The summer warbler is, if possible, even
more completely beneficial in its food habits than the Audubon
warbler. Its animal food in relation to man is almost entirely nox-
ious or neutral, and it eats so little vegetable food that its character is
of but slight consequence.

WESTERN YELLOWTHROAT.
(Geothlypis trichas subspp. )

In California the yellowthroat is an inhabitant of marshes and low,
bushy places among tules or willows. While it is an insect eater of
9379—No. 30—-07——4 ©

50 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

the highest order, it does not so directly affect the interests of horti-
culture as it would if it frequented orchards and gardens. It may be
said, however, that as the swamps and thickets in which it lives are
the recruiting grounds for many orchard pests, the bird that destroys
them in their native haunts is by no means without economic value.

In a somewhat restricted investigation of the food of this bird 114
stomachs, taken in every month except January, were examined.

Vegetable food —A few seeds and bits of rubbish is the sum total of
the vegetable food, and it is probable that these were taken accident-
ally. Some of the ants of California store up seeds, and when snap-
ping up ants the yellowthroat probably takes the seeds along with
them.

Animal matter.—The animal matter amounted to 99.8 percent of
the total food. The largest item is Hymenoptera, amounting to 35
percent, of which about half is ants and the remainder wild bees,
wasps, ete.

Hemiptera amount to 28 percent, and are made up of leaf-bugs,
leaf-hoppers, tree-hoppers, plant-lice, scales, and probably some others
not identifiable. The black olive scale was found in a few stomachs
and plant-lice in one, but the other families were a pretty constant
component of the food in every month:

Beetles were eaten to the extent of nearly 15 percent, and are mostly
harmful species, the exception being a few coccinellids of the genus
Scymnus, which, however, do not amount to 1 percent of the whole.
Weevils and others of the more common families make up the rest of
this portion of the diet. The three orders of insects mentioned above
form the great bulk of the food of the vellowthroat, and are regularly
eaten throughout the year.

Caterpillars and moths comprise 5 percent, but, so far as the
stomachs at hand show, are eaten very irregularly and do not appear
on the preferred list. The same may be said of Diptera, though they
amount to 12 percent, but in several months none were eaten. Grrass-
hoppers were found in only four stomachs, but one of these contained
nothing else. Spiders are taken to the extent of nearly 4 percent, but
in some months none were found and only a trace in others.

From the above rather brief survey of the food of the yellowthroat
itis evident that the horticulturist has nothing to fear from this
bird should it change its habitat and become an inhabitant of
orchards and vineyards. It is practically wholly insectivorous, and
ihe insects it eats are either harmful or of little economic value. It
eats no fruit or grain, nor, so far as known, any other useful product.
Like other members of the family, its life is passed in unceasing
search for insects.

¥&

WARBLERS. | D1
ORANGE-CROW NED WARBLER.
(Helminthophila celata subspp.)

The genus Helminthophila is next to Dendroica in the number of
species and subspecies it contains, but still falls far below it. Several]
species occur in California, but the one under consideration is prob-
ably the most important. Only 65 stomachs were available for exami-
nation, but they confirm the evidence already obtained from other
species.

Vegetable food.—Less than 9 percent of the food is vegetable mat-
ter, and is made up of 3 percent of fruit and rather more than 5 per-
cent of various substances, such as leaf galls, seeds, and rubbish.
Fruit was found in only a few stomachs, but the percentage in each
was considerable; figs were the only variety identified. |

Animal food —The animal matter in these stomachs amounts to 91
percent of the food. Hemiptera are the largest item and amount to
over 25 percent, mostly leaf-bugs, leaf-hoppers, plant-lice, and scales.
Plant-lice were found in only one stomach and scales in 5, of which 3
contained the black olive species. Beetles amount to about 19 percent
of the food, and with the exception of a few Coccinellide are of
harmful families, among which are a number of weevils.

Beetles and bugs are the two orders of insects that are not only
eaten to the greatest extent but are taken with great regularity, and
form a respectable percentage of the food in every month.

Caterpillars are eaten rather irregularly, though they aggregate 24
percent for the vear. Stomachs collected in several months contained
none, while in others they amounted to more than half the food.
Probably the examination of a greater number of stomachs would
show more regularity in the consumption of these insects.

Hymenoptera amount nearly to 15 percent, and are mostly small
wasps, though some ants are eaten. This is the smallest percentage
for this order that has yet been found in the food of any warbler.

Flies are represented by less than 1 percent, which is unusually
small. Perhaps this warbler lacks the skill to catch such agile
insects. Seven percent of spiders were feund in the stomachs, the
largest percentage of these creatures for any warbler. This again
indicates that the crange-crown 1s most successful in hunting slug-
gish game, such as beetles, bugs, and spiders.

GOLDEN PILEOLATED WARBLER.

(Wilsonia pusilla subspp.)

The golden pileolated warbler is another of the small birds that
summer here and there on the Pacific coast, mostly in willows and

’

52 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

other shrubbery, but not rarely in the orchard. During the migra-
tion 1t is common and widespread.

Fifty-two stomachs of this bird have been examined, and though
the evidence is somewhat fragmentary, it suffices to reveal the general
character of the food.

Animal food—Animal matter amounts to over 93 percent, vege-
table to less than 7 percent. Of the former, the larger item is Hemip-
tera, which aggregates over 35 percent. The black olive scale was
found in four stomachs, but leaf-hoppers make up the bulk of this
portion of the food. Hymenoptera stand next in importance, with 31
percent, made up of both wasps and ants.

Fhes are eaten to the extent of 11 percent, and in connection with
the Hymenoptera proves what observation of its habits indicate, that
this bird gets much of its food when on the wing. A good many of
the insects were the tipulids, or crane-flies.

Beetles of half a dozen different families were eaten to the extent
of about 9 percent. They were mostly leaf-beetles (Chrysomelidee) ,
with a few weevils and one or two others. No coccinellids were
found.

Somewhat less than 5 percent of the food consists of caterpillars.
They do not appear to be favorite food, for they are eaten very
irregularly. Spiders also are taken only sparingly, and form but
little more than 1 percent of the total food.

Vegetable food——The vegetable food, less than 7 percent of the
total, is made up almost entirely of fruit pulp, and was eaten in the
months of September and October.

SUMMARY.

The foregoing hasty review of the food of the golden pileolated
warbler shows that its food habits are practically the same as those
of other members of the family. The food is largely composed of
insects, and its two most prominent elements are Hymenoptera and
Hemiptera, which are eaten extensively and very regularly through
the year. The other components of the diet apparently are taken
with less regularity.

WESTERN MOCKING BIRD.

(Mimus poiyglottos leucoptérus. )

The mocking bird has always been held in such high esteem as a
singer that perhaps it would be useless to attempt to add to the
bird’s repute by showing that its food habits are of a high order of
economic interest. Moreover, the title of the mocking bird to be
ranked as an economic benefactor is not quite clear, for, though it

WESTERN MOCKING BIRD. ~ 53

does considerable good by the destruction of harmful insects, it eats
much fruit, and from the Southern States, particularly Texas and
Florida, where fruit raising is an important tdustry, have come
bitter complaints against it. In Florida the bird is said to attack
grapes and oranges, and in Texas it is asserted that figs are to be
added to its food list.

In California the mocking bird is a common resident only in the
southern half of the State and is very common only in restricted
portions. No serious complaints of the bird’s depredations in this
State have yet been made, but this perhaps is due to the fact that
mocking birds are rare in sections where cherries and the smaller
deciduous fruits are grown. Where mockers are most abundant,
citrus fruits are the principal crop and the birds do not appear to
molest them.

While a number of stomachs of this bird have been examined, they
are too few and too unequally distributed over the region under
investigation to justify final conclusions with regard to the animal
food; still they furnish information of value. It so happens that
33 stomachs were taken between July 18 and August 18, and another
a few days later. All but one of these stomachs were from the region
about Los Angeles, and this one was collected at Fresno. The av-
erage, therefore, is a little more than one stomach a day for this
period, and gives a fair idea of the food for the time and locality.

The first analysis gives 23 percent of animal matter and 77 percent
of vegetable. There was no stomach which did not contain some
vegetable food, while 10 had no animal matter.

Animal food.—Beetles of several families formed a little less than
1 percent. Hymenoptera, largely ants, were eaten to the extent of
somewhat more than 10 percent. Grasshoppers constituted the larg-
est item of animal food, and amounted to 11 percent of the whole.
A few caterpillars and spiders made up the other 1 percent of the
animal food.

Vegetable food—Of the 77 percent of vegetable food nearly 74
percent was diagnosed as fruit. Some of this, of course, was wild,
but blackberries or raspberries, grapes, and figs were found in many
stomachs. Many of the birds were taken in orchards and gardens,
and some were shot in the very act of pilfering blackberries. Others
were taken in a wild arroyo away from cultivation. The only species
of wild fruits that were identified were elderberries, which were
found in a few stomachs. The other vegetable matter was made up
of several elements. Of these, the seeds of poison oak (PI. II, fig. 9)
are perhaps the most conspicuous, and one stomach was entirely filled
with them. A few weed seeds and some rubbish completed the vege-
table part of the food.

54 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

Besides the 34 stomachs already discussed, 19 others were examined,
but as they represent nine months of the year they are too few to
afford a criterion of the usual food for those months; but they give
a hint at least of what is eaten at other times than midsummer.
Two stomachs were taken in March, one of which was filled with ani-
mal food, and the other also, except 1 percent of vegetable rubbish.
The animal portion consisted of harmful insects, except one lizard.
This seems peculiar food for a mocking bird, and is to be considered
beneficial. The one stomach taken in May was filled with seeds of
poison oak. A stomach collected in June contained 8 percent of
caterpillars; small fruit, probably wild, constituted the rest of the
contents. Six stomachs taken in August contained 22 percent of
animal matter to 78 of vegetable. The animal food consisted of
beetles, ants, and grasshoppers. The vegetable portion was made up
of some wild grapelike fruit and a little fig pulp with some elder-
berries: Of four stomachs taken in September, one was filled with
insects and spiders. The three others contained a few wasps, with
fruit and other vegetable matter. The only insect to be considered
useful was one carabid beetle. Of the three stomachs collected in
October, one was filled with the seeds and pulp of grapes and figs;
one contained 27 percent of grasshoppers and 73 percent of some wild
berry not positively identified, while the third contained a few grass-
hopper remains and 92 percent of wild seed. The stomach collected
in December was filled with seeds and pulp of figs and grapes. One
stomach was taken in January which contained 70 percent of harmful
insects and 30 percent of seeds of poison oak.

FOOD OF YOUNG.

Among these stomachs was one of a nestling about a week old. It
contained 92 percent of grasshoppers and crickets and 8 percent of
some wild fruit. So far as it goes, this indicates that mockers follow
the general rule and’ feed their young largely on animal food of the
softer kind—that is, grasshoppers instead of beetles.

SUMMARY.

Reviewing the contents of the 52 stomachs we find 29 percent of
animal matter and 71 of vegetable. Of the animal food the largest
item is Hymenoptera, 10 percent, and then in order, Orthoptera 7
percent, Coleoptera 6 percent, Lepidoptera 5 percent, miscellaneous 1
percent. The vegetable food consists of 50 percent of fruit and 21
percent of seeds and other items. These results prove that the mock-
ing bird eats insects to a considerable extent, but they are not con-

CALIFORNIA TILRASHER, 55

clusive as to the elements of its preferred diet. It is evident that it
is fond of fruit, and where abundant the bird may become a menace
to the orchard and vineyard.

CALIFORNIA THRASHER.

(Toxrostoma redivivad.)

Thrashers are eminently birds of the underbrush. While they
occasionally alight on trees at some height from the ground, thes
are more frequently seen under bushes or skulking out of sight in
some almost impenetrable thicket of briars. When, however, the
thrasher wakes in the morning and feels his soul overflowing with
song, he perches on the topmost twig of a tree and lets the world
know that he is there and believes that life is worth living.

The food of the thrasher is obtained on or near the ground. The
long curved bill of the California species is probably used much as
many birds use their claws to dig among dead leaves and other rub-
bish for insects. The bird is not fastidious in its diet, and examina-_
tion of the stomachs reveals a good many bits of dead leaves, rotten
wood, plant stems, which are carelessly taken along with more
nutritious morsels. |

An examination of 82 stomachs of this species shows that vegetable
food exceeds the animal in the proportion of 59 to 41. In.the eastern
species (7. rufum) the ratio is 36 to 64. This result is rather sur-
prising, for, as a general rule, California birds eat a larger propor-
tion of animal food than do the most nearly related eastern species.

Animal food.—As the thrasher is eminently a ground forager it
would naturally be expected to find and eat many ground-living bee-
tles. Of these the Carabide are the most important, owing to their
predaceous habits; so a separate account of this family was kept.
The result shows that they enter the food of the thrasher to the extent
only of 3.8 percent, while all other beetles amount to nearly 6 percent.
Of these, the darkling beetles (Tenebrionide) are the most numerous,
and the May beetles (Scarabeeide) next. But very few weevils or other
species that live on trees or foliage were found. Of all the insects,
Hymenoptera are the most abundant, as they are also the most con-
stant element of the thrasher’s food. About half of these are ants,
the rest wasps and bees. Ants naturally are the insects most often
found by this bird, as many species live on the ground and among
rubbish and rotten wood. The occurrence in the food of wasps and
bees, on the contrary, is somewhat of a surprise, as they are mostly
sun-loving insects more often found on flowers or the leaves of trees
than under bushes or thickets where the thrasher delights to forage.
Together they make up something more than 12 percent of the food

56 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

of the year. Two specimens of worker honey-bees (Apis mellifera)
were found in one stomach. None of the other Hymenoptera was of
specially useful species.

Caterpillars, cocoons, and moths amount to a little more than 8 per-
cent of the food, and the greater number were eaten during the win-
ter months. It is probable that they were hibernating and were
raked out from under dead leaves or other rubbish. A few bugs,
flies, grasshoppers, and spiders make up the rest of the animal food—
about 6 percent. Spiders and myriapods amount to a little more than
6 percent. ;

Vegetable food——The vegetable food may be divided into three
parts: Fruit, poison-oak seeds, and miscellaneous vegetable matter.
Fruit represents nearly 18 percent, but it probably is not of much
value. Several stomachs contained pulp that could not be identified
with certainty, and might have been that of some cultivated variety.
Seeds of Rubus fruits (blackberries or raspberries) were found in 12
stomachs out of the $2. These, however, are as likely to have been
wild as cultivated. Elderberry seeds were discovered in 10 stomachs,
Cascara, or coffee berries (Rhamnus californicus),in 5,and manzan-
ita berries in 1. The seed of poison oak (hus diversiloba, Pl. I,
fig. 9), and a few of the nonpoisonous species of Rhus were eaten to
the extent of 14 percent of the food. They were not found in many
stomachs, but appear to be eaten in considerable quantities when
eaten at all. The thrasher must be added to the list of birds that
assist In the dissemination of the seeds of this noxious plant.

The miscellaneous part of the vegetable food amounts to over 26
percent, and is made up of mast, weed seed, galls, and rubbish. The
mast was not further identifiable. Most of the seeds were so broken
and ground up that only a few species were identified. Two stom-
achs contained remains of grain—wheat in one and corn in the other.
Leaf galls were found in several stomachs, and rubbish in quite a
number, though here again it is difficult to draw the line between food
proper and stuff that is accidentally picked up with it.

SUMMARY.

Although the thrashers eat some fruit, most of it is wild and of no
value. Moreover, the bird’s habits are such as to preclude the hke-
lihood that it will ever become a resident of orchards. Grain eyi-
dently is not a favorite food, and if it were it is doubtful if the bird
would leave its chosen haunts for the sake of procuring it. It is not
probable that the California thrasher will ever become of special
economic interest unless under very exceptional circumstances. In
the meantime it performs its part in the great work of reducing the
vast numbers of insects.

WRENS. 57
WRENS.

Since the time to which history runneth not the wren family, rep-
resented by one or other of its members, has attached itself to the
abodes of man. Wherever man settles some member of this group is
ready to greet him, to take advantage of his improvements, and to
aid in the fight against his insect enemies. The common wren of
furope and the house wren of eastern North America habitually
choose crannies in buildings or fences for nesting places, or if hollow
trees are selected they usually are near human dwellings, preferably
fruit trees in orchards or gardens. When civilization was pushed to
the Pacific coast, wrens were there ready to welcome the new order of
things. In food habits the wrens proper (‘Troglodytine) are largely
insectivorous. While occasionally they eat a seed or a bit of fruit,
the quantity taken by most species during the year is so small in
comparison to the animal portion as to be insignificant. The insects
saten by the wrens are mostly noxious species, such as infest the
foliage and branches of trees and shrubs, and the domestic habits of
the wrens enable them to attack these pests in the very places where
they are most harmful—that is, in the garden and orchard. The
predaceous beetles (Carabidae), which live mostly on the ground, are
protected from the wrens by this very habit, as the latter seldom for-
ages in such places. Moreover, the species most valuable to man are
‘ather large prey for such small birds.

BEWICK WREN.
(Thryomanes beiwicki subspp. )

The Bewick wren is one of the species which to a considerable
extent occupies in California the place of the house wren in the East-
ern States. The nesting habits of the two are practically identical,
and the economic value of the former is just as great as that of the
latter.

Investigation of this bird’s food is based upon the examination of
146 stomachs taken in every month of the year. Of its diet for the
year a little more than 97 percent consists of insects and less than 8
percent of vegetable matter.

Vegetable food—The largest quantity of vegetable matter was
eaten in December and January and formed about 12 percent of the
food in each of these months. In three months—March, June, and
September—no vegetable food was found in the stomachs. It is
hardly probable, however, that such would always be the case in these
months. What was supposed to be pulp of fruit was found in one
stomach. This was the only vegetable substance noted that could pos-
sibly be useful to man. Six stomachs contained seeds more or less
broken, of which only one was identified, a single seed of turkey

58 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

mullen (A remocarpus setigerus). In one stomach was a small gall,
and in six were various substances, sueh as bits of dead leaves, plant
stems, and rotten wood, which may properly be denominated rubbish.

Animal food—Oft the animal food various families of bugs
(Hemiptera) make up the largest percentage. One of the most
interesting items is the black olive scale, which was found in a num-
ber of stomachs but does not appear to be eaten extensively. The
great bulk of the hemipterous food was made up of leaf-bugs, stink-
bugs, shield-bugs, leaf-hoppers, tree-hoppers, and jumping plant-lice,
though there were representatives of other families. The aggregate
of the Hemiptera eaten is about 31 percent of the total food. It is
distributed with great regularity through the year and varies less
from month to month than any other food. With the exception of
the olive scale no specially harmful species was identified, but bugs
belonging to the same family as the notorious chinch bug were found.
As avast majority of the members of this order are injurious to
vegetation their destruction by birds must be considered beneficial.

Beetles collectively amount to over 21 percent of the food. They
may be placed in three groups—ladybirds, weevils, and other beetles.
Ladybirds are probably the most useful imsects of the whole order
of Coleoptera, so that their destruction by birds is to be deplored.
Bewick’s wren eats them to the extent of a little more than 3 percent
of the whole food. This is not a large percentage, though greater
than could be wished. On the other hand, the bird eats weevils, or
snout-beetles, to the extent of nearly 10 percent of its food. As all
the members of this group (Rhynchophora) are practically harmful,
and some of them the worst pests of the orchard and forest, it must
be allowed that we are paid for our ladybirds at a fairly good
price. A number of stomachs contained beetles of this group belong-
ing to the family of engravers (Scolytide), which live under the
bark of trees and greatly damage the timber. The stomachs of two
wrens taken in Pacific Grove in the month of January contained
85 and 80 percent of these beetles.

The owners of the Pacific Grove pine forests have engaged the
services of an expert to investigate the damage being done to the pines
by scolytids and other insects, and, if possible, to devise a remedy.
Is it not evident that the bird under consideration is one of Nature’s
remedies for this evil? The trouble is that there are not enough
birds to wage effective war against the insects. In many cases, per-
haps in this one, man himself is partly to blame for present condi-
tions. The birds are destroyed—destruction of the forest follows.
By furnishing proper facilities for breeding in the shape of bird
boxes the numbers of this wren in the State of California may be
ereatly increased and the forest trees correspondingly protected from

insects.

WRENS. ; HQ

Other beetles, mostly leaf-beetles (Chrysomelid#) were eaten to
the extent of a little more than S percent. While nearly all of the
leaf-beetles are theoretically harmful none of those identified in the
food are especially destructive to crops.

Hymenoptera, including both ants and wasps, aggregate a little
more than 17 percent of the wren’s diet. They are a fairly constant
constituent of the food and do not appear to vary much according to
season. The greater number was found in March, but as only two
stomachs were -collected in this month the record is not conclusive.
Ants form about 7 percent of the food. The economic relations of
these insects have been discussed elsewhere. Wasps make up the rest
of the item, about 10 percent, and have no especial economic signifi-
eance. Caterpillars and a few moths and some cocoons constitute a
little less than 12 percent of the wren’s food. Contrary to what
might be expected, not all these are taken in summer. The 14
stomachs obtained in February contained caterpillars to the amount
of over 13 percent of their contents. They were probably found
hibernating in crevices of bark. A few moths were eaten, but, as
usual, they were only a small item of the food. Small cocoons of
tineid moths were found in a number of stomachs.

Grasshoppers amount to 4 percent of the wren’s diet. Most of
them are eaten during the summer and fall, though some appeared in
stomachs taken in January. While these insects are a favorite food
for many birds they are probably rather large and too terrestrial in
habits to be eaten in great numbers by wrens. Other insects, mostly
flies and a few remains which could not be identified, make up about
6 percent of the stomachs’ contents. Flies (Diptera) are eaten very
irregularly and appear not to be relished. Spiders are taken to the
extent of somewhat more than 5 percent of the total food. As spiders
live about trees, bushes, fences, rocks, and outbuildings it is not sur-
prising that they are captured by wrens, but the rule seems to be that
while all insectivorous birds eat spiders to some extent no species eats
many.

List of insects found in stomachs of Bewick wren:

COLEOPTERA.

Cercyon fulvipenne. Diabrotica soror.
Hippodamia convergens. Cryptocephalus castaneus.
Cocinella t. californica. Gastroidea sp.

Ncymnus marginicollis. Bruchus seminulum.
Aphodius rugifrons. Blapstinus dilatatus.
Microrhopala montana, Notorus alameda.
Diachus auratus. Ceutorhynchus nodipennis.
Crepidodera helrines. Pelenomus cavifrons,
Hpitrir parvcula. Apion sp.

Ewrema conspersa,

60 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

HEMIPTERA.
Sinea diadema. Naissetia olew,
Remains of insects belonging to the following famihes were found,

but not further identified :

COLEOPTERA.

Carabidee. 5ruchide.
Hydrophilidee. Tenebrionide.
Staphylinide. Anthicidee.
Coccinellidee. Curculionids.
Elateridie. Scolytidee.
Scarabeidie. Other Rhynchophora.

Chrysomelidz.

DIPTERA.
Muscide. Tipulidee.
HEMIPTERA.
Emeside. Corimelzenidee.
Reduviide. Scutelleride.
Aradide. Jasside.
Capside. Membracide.
Lygeide. Psyllidee.
Pentatomide. Coeccidee.

WESTERN HOUSE WREN.

(Troglodytes aedon subspp. )

The western house wren, like its eastern relative, is a common
resident about outbuildings and other structures that offer suitable
nesting sites and good foraging ground. In its general appearance
and habits it is so hke the Bewick wren that the casual observer is
hkely to confuse the two. Like other members of the family, it is
largely insectivorous and rarely eats vegetable food.

Only 36 stomachs of this species from California are available for
examination, but the character of the food agrees so nearly with that
of the eastern form that the general results obtained from the study
of that subspecies may be applied to the western bird.

Animal food.—In the 36 stomachs examined animal matter, con-
sisting entirely of insects and spiders, formed 97.5 percent, and vege-
table food 2.5 percent. Beetles, as a whole, amount to about 20 per-
cent; caterpillars, aggregating 24 percent, are taken in the earher
months of the year; and Hemiptera, amounting to 33 percent, are
eaten chiefly in the last of the season. Grasshoppers amount to about
5 percent, and different insects, mostly ants and other Hymenoptera,
aggregate 15 per cent.

Vegetable food —The vegetable matter consists of rubbish and one
grass seed, probably all of it swallowed accidentally.

WRENS. 61

Among the 36 stomachs, of which the record has just been given,
were 18 nestlings, some being about a week old, others about ready
to leave the nest. The results of the examination of these were tabu-
lated by themselves in order to determine the differences, if any,
between the food of the adults and that of the young. No vegetable
matter was found in any of the stomachs, and the animal food was
distributed among a comparatively few elements. Bugs (Hemiptera)
are the largest item, and amount to nearly 36 percent. Caterpillars
and grasshoppers stand next, with 17 and 16 percent, respectively.

It is interesting to note that about three times as many grasshop-
pers are fed to the young as are eaten by the adults. Wasps and ants
amount to a httle more than 6 percent, and are the smallest item.
Spiders appear to the extent of a little over 11 percent. Beetles,
however, constitute the most interesting item of the food. They
were eaten to an average extent of somewhat more than 11 percent,
and were nearly all ladybirds (Coccinellide) contained in the stom-
achs of five individuals of a brood of six. The amount in each
stomach varied from 15 to 65 percent of the contents, and averaged
29 percent of each of the six birds. It is a question which is the more
surprising, that this brood had eaten so many coccinellids, or that
the others had eaten so few. Only three other stomachs contained
any of these beetles and those were all adults. The house wren does
not exhibit any special proclivities for ladybirds, and it would seem
probable that in this case either other food was wanting or these
beetles were specially abundant.

In addition to the examination of stomachs, observations were made
upon the feeding of nestling wrens. A nest situated in the porch of
the house of Mr. W. O. Emerson, at Haywards, Cal., was observed
for one-hour periods from soon after the young were hatched until
they were nearly ready to fly. The nest was watched at various times
of day, so as to include as nearly as possible all hours of daylight.
During the first two periods the male aided in feeding the young,
but afterwards was not seen, and the whole care of the young de-
volved upon the mother. The number of young probably was not
fewer than six. Following are the results in tabular form:

Forenoon. Afternoon.

Date.

Hour of ob- Nur EE Hour of ob- Number |
servation. Pouniirien, servation. raatinipn. %
May 18... 10. 00-11. 00 8 1. 00-5, 00 7
May 19... 9, 35-10. 35 13 4. 30-5. 30 10
May 20... 10. 29-11. 29 fa St eS as eae | aoe ais
May 21...) 8. 23-— 9. 23 20 2. 01-8. 01 Lael
May 23... 8. 22- 9, 22 1 1) (i 2 ea eae (hee
May 26... 10. 35-11. 35 Li bream aes 4. Nera Ee
iN Rinne (SS 3 | A et a ee 6S on Pome Ie Ah 2. 36-3. 36 | Sl |
May 28... 8. 20- 9.20 SG pede mi eee cI te on kw

Mav 30..., 10. 40-11. 40 A ae cafes tei tata ke Sal xiwere new onl

62 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

As will be noticed, the whole time of observation covered a period
of thirteen days, although the nest was not watched every day. In
all the nest was watched for twelve hours, and the total number of
times that food was brought to the young was 234, or an average of
194 times per hour. The young were fed as early as 5 o’clock in the
morning and as late as 7 in the evening, thus making for the parent
birds a working day of fourteen hours. Only a little plain arithmetic
is necessary to show very nearly the number of insects destroyed by
this family in a single day.

These observations were made with watch in hand and the time of
each feeding noted. In many cases the parent bird was away In
search of food only half a minute. Once there was a heavy mist
nearly all day, when the mother wren was hard pressed to find food
for the ever-gaping mouths of her young. No flying insects were
abroad, and the supply of caterpillars from the immediate vicinity
had been exhausted. In this extremity the mother turned her atten-
tion to spiders and was seen to visit*the interior of a summer house,
also to investigate a pile of flower pots and tubs and to plunge into
and under an evergreen hedge in search of something that would
answer for food. As the nest was watched at very short range, it was
often possible to determine the nature of the food brought by the
parent. When the nestlings were very young, it consisted almost
entirely of small green caterpillars, commonly called ‘ canker-worms.’
Later this was varied by tipulid flies (daddy-long-legs), small moths,
and spiders. Some of the imsects brought were not determinable,
probably flies and wasps.

SUMMARY.

Irom the above sketch of the food of the house wren it will be seen
that there is practically only one item to which exception can be taken,
namely, the coccinellid beetles, or ladybugs. But the record is so
meager that it 1s not safe to draw general conclusions. It is probable
that a more extensive investigation of the food of the California bird
will show that it is entitled to the same high economic rank as its
eastern relative.

WESTERN ALARSHL WREN.
(Teimatodytes palustris subspp.)

The marsh wren, as its name indicates, is a resident of swamps
and marshy grounds. At first thonght its food might not appear to
be of any economic importance, but investigation shows that it does
not differ from that of the orchard wrens as much as one might infer’
from difference of habitat. Only 53 stomachs of this species have
been obtained for examination. While this number is not sufficient
asa basis for final judgment, it suffices to show how closely the food
of this species resembles that of its congeners.

WRENS. | 63
Vegetable food.—But little vegetable food was found in the stom-
ach of the marsh wren, and the precise value of most of that was not
determinable. A few seeds of sedge and one of amaranth were all
that were identified. The total amount was a trifle over 2 percent.
Animal food—Beetles, wasps, ants, bugs, caterpillars, and a few
miscellaneous insects, with some spiders and snails, make up the
bill of fare. As with the Bewick and the house wren, bugs are the
largest item, but do not quite equal the quantity eaten by those indus-
trious bug-hunters. While the Bewick eats these insects to the extent
of 31 percent of its food, the marsh wren eats them only to the amount
of 29 percent. In this respect there seems to be little difference
between the bird that gets its food from trees and the one that feeds
among the tules and sedges. The families represented are those of
the assassin-bugs, damsel-bugs, leaf-bugs, stink-bugs, leaf-hoppers,
and tree-hoppers, most of which are usually found on trees—in fact,
one is forced to the conclusion that the marsh wren must at times
forage upon trees or shrubs. Scales were found in one stomach,

which is another point of resemblance between the diet of this bird
and that of the habitual tree inhabiters.

In the marsh wren’s food caterpillars and chrysalids rank next to
bugs in importance. They amount to about 17 percent of the whole,
and appear in the food of every month. Cocoons of tineid moths
were contained in a number of stomachs, another indication that the
birds visit trees.

Beetles constitute 16 percent of the food. While a number of the
commoner families are represented, the terrestrial forms are rather
more prominent than in the food of the arboreal wrens. A few cara-
bids and a number of coccinellids together make up 2 percent of the
food, and were the only useful insects eaten, unless the assassin-bugs
are reckoned as such. As these feed on other insects they must of
course do some good. Ants and wasps amount to about 8 percent
of the food, and most of them were eaten during the fall months.
Flies, grasshoppers, dragon-flies, and a few insect remains not fur-
ther identified make up over 11 percent of the food. They were
eaten. very irregularly. Spiders constitute somewhat more than 5
percent, and, as usual, ave very regularly eaten, but in small num,
bers. Small mollusks (snatls) were eaten by quite a number of birds,

and 1 stomach contained 11 specimens.
SUMMARY.

This brief review of the food of the marsh wren, while not abso-
lutely conclusive, is sufficiently near the truth to prove that the bird
is to be ranked among our eminently useful species. Of some birds it
has been said that their peculiar merit les in the fact that they
reside in orchards and cultivated ground and hence destroy insect

64 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

pests in the very places where their mischief is done. This can not
be asserted of the marsh wren, but it must be remembered that many
harmful species of insects breed and live in marshes and waste places
as well as in grainfields and orchards, so that the birds which
destroy them on wild lands are removing the source of supply from
which are recruited the hosts that infest the farm.

CACTUS WREN.
(Heleodytes brunneicapillus. )

(Bl TY)

The cactus wren is so exclusively a bird of the desert and waste
places that its food may be thought to have little, if any, economic
interest. It is not safe to assume, however, that the bird will never
affect the interests of agriculture because it does not do so at present.
Moreover, its food habits have a scientific interest which justifies a
brief review. A number of the birds whose stomachs have been
examined for this work were taken near orchards and grainfields,
and there can be little doubt that, with the spread of cultivation, the
species will adapt itself to a somewhat different environment and
become of economic importance. We find, in fact, that its food is
made up of practically the same orders and familes of insects that
compose the diet of birds hving on agricultural lands, but the relative
proportions differ widely, and in most cases the species are probably
different.

Only 41 stomachs of the cactus wren were available for examina-
tion. They were taken in the region from Los Angeles to San Ber-
nardino, and from July to January, inclusive. They contained about
83 percent of animal matter to 17 of vegetable.

Animal food—Beetles and Hymenoptera, the latter ants and
wasps, were the two most important items of the animal food. Each
made up about 27 percent of the total. The beetles belong to several
families, but..weevils, or snout-beetles, were the most noticeable, and
amount to somewhat more than 10 percent. One stomach contained
11 of these insects and another 10, while others held fewer. Only
oue species, Rhigopsts effracta, was identified. Five of these were in
1 stomach. The cther beetles belong to more common families.
Coceinellids were found in 1 stomach and carrion beetles in 2.
They were the only insects noted that can be considered as useful.
Hymenoptera are represented by many ants and a few wasps. These
are just the insects which the cactus wren might be expected to find,
for dry land and sunshine are the conditions which favor these crea-
tures. Grasshoppers amount to 2 little more than 15 percent. This

PLATE IV.

Bull. 30, Biological Survey, U. S. Dept. of Agriculture.

ASS 84

2=~ed Or

4e
ae

—

CACTUS WREN (HELEODYTES BRUNNEICAPILLUS COUES!I).

WRENS. 65

is the only wren that eats these insects to any considerable extent
except as nestlings. |

Bugs (Hemiptera) amount to only a little more than 5 percent of
the food, which is the smallest quantity eaten by any of the wren
family. This item, however, contains one unexpected element—that
is, black scales (Saissetia). These appeared in 6 stomachs, and must
have been obtained from trees or shrubs, possibly from fruit trees.
Tm any case their destruction is a welcome service. Caterpillars and
their allies (Lepidoptera) were eaten to the extent of a little more
than 5 percent. Among them were many cocoons of tineid moths,
indicating again that the cactus wren obtains some of its food from
trees and shrubs. A few unidentifiable insects and spiders amount
to somewhat more than 3 percent. ‘This is the smallest record for
spiders of any of the wren family, which is much given to eating
these creatures, finding them in crannies in rocks, stumps, and other
places. A few of the long bones of a tree frog were found in 1
stomach.

Vegetable food —Seventeen percent of vegetable matter was found
in the stomachs of this bird. This is the largest percentage found
in the stomachs of any species of wren yet examined. The vege-
table food of the cactus wren consists of fruit pulp and weed seeds.
The former amounts to nearly 13 percent, but in all cases where
identification was possible consisted of wild species. Of these, only
3 were fully identified—cactus (Opuntia), elderberry (Sambucus),
and Cascara> (Rhamnus), the last only in 1 stomach. Nothing
was found to indicate that cultivated varieties had been eaten.
Seeds, which amount to 4 percent, are those of the poison oak (Rhus),
and a nonpoisonous species, with filaree (Erodium) and Amisinckia,
most of them useless plants or worse.

SUM MARY.

From this brief inspection of the cactus wren’s food it is seen that
it contains but little that is useful to man, while the great bulk is
made up of elements that are, or would be, harmful if present on
cultivated lands. The bird thus sustains the good reputation of
the rest of its family.

OTHER WRENS.

Some half a dozen stomachs each of the western winter wren (Olbior-
chilus hiemalis pacificus) and dotted canyon wren (Catherpes mexi-
canus punctulatus) and the rock wren (Salpinctes obsoletus) have
been examined. This number is entirely too small to serve for
specific statements in regard to their food except that it may be said

937T9—No. 30—O7

66 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

that it corresponds closely to that of the other species of the family
discussed in foregoing pages.

From this somewhat limited investigation of the food of the
California wrens several points may be regarded as established:
(1) That these wrens are essentially insectivorous; (2) that an over-
whelming majority of the insects composing their food are harmful
species; (3) that the quantity of vegetable food eaten is so small as
to have no economic importance.

CALIFORNIA CREEPER.
(Certhia familiaris occidentalis. )

Only 7 stomachs of the California creeper were available for
examination, but they confirm the good opinion observers have
formed of the habits of this bird. Like the titmice and nuthatches,
the creeper is an indefatigable forager on the trunks and branches
of trees, and the food it obtains there is of the same nature—that is,
small beetles (many of them weevils), wasps, ants, bugs, caterpillars,
and a few spiders. Of the 7 stomachs examined, only 1 contained
vegetable food, and this had only 19 percent of seed, too much digested
for identification. 3

While the creeper is not systematically classed with the nuthatches
and titmice, its food habits closely ally it to these birds and to the
wrens, and whatever good is true of them applies with equal force
to the creeper.

NUTHATCHES AND TITMICE.

(Paride. )

Few families of birds contain so many absolutely harmless and
thoroughly useful species as that of the nuthatches and titmice. All
of the American species are small, and several are so minute that the
larger species of humming birds exceed them in size. In colors they
are neither’ brilliant nor showy, black, white, brown, and gray being
the predominant tints of their plumage. In manners and voice they
are equally unobtrusive, and so-little do their movements attract atten-
tion that one may be surrounded by them in the forest before he is
conscious of their presence. More than forty species and subspecies
of the titmouse family reside within the limits of the United States,
of which some fifteen live in California.

From an economic standpoint the titmice are the reverse of insig-
nificant. They are essentially inhabitants of trees and shrubs, and
obtain almost their entire living from them. Their food consists
largely of small insects and their eggs and larvee, and, as the individ-
uals of most of the species are numerous and spend all the daylight
hours searching for food, it follows that the number of harmful

NUTHATCHES AND TITMICE. 67

reatures they destroy is beyond calculation. As conservators of
orest and orchards there are few birds that compare with them.
he insects they destroy are largely those that feed upon the leaves,
lossoms, and fruit of trees, with some that bore into the wood or
urrow under the bark, thereby injuring or killing the tree itself.
On the other hand, they do not prey upon fruit, grain, or other prod-
ict of husbandry. The small amount of vegetable matter they eat
consists principally of small galls, whose destruction is a benefit, with
a few seeds and a little wild fruit.

PYGMY NUTHATCH.
(Sitta pygmea.)

The nuthatches are small, inconspicuous birds that live upon trees
‘and for the most part remain in forests or groves, though not rarely
visiting the orchard. While allied to titmice they form a fairly well-
defined group and can be easily distinguished from titmice proper.
As gymnasts they probably lead the avian world. After watching
their movements one might suppose that nature had quite exempted
them from the operation of the laws of gravity, as they move up or
down a tree with equal facility, or along the underside of a horizontal
branch where they inspect a promising,knot hole or cranny, appar-
ently without the least idea that they are upside down. The food
they obtain from trees is of the same general character as that of the
rest of the titmouse family.

Unfortunately only a few stomachs of these birds are at hand for
examination—enough, however, to give a general idea of the diet.
The pygmy nuthatch is the smallest of the group, but as a
destroyer of noxious insects it is far from insignificant. Only 31
stomachs of this feathered midget are available for examination, but
the number is sufficient to bring out some strong points of the bird’s
diet. The relative proportions of animal and vegetable food, as indi-
eated by the contents of these stomachs, are approximately 83 percent
of the former to 17 percent of the latter.

Animal food —The largest item of animal food is Hymenoptera,
composed mostly of wasps, with a few ants. They amount to about
38 percent of the whole. Next in order are Hemiptera, aggregating
23 percent. A large proportion of these belong to the family Cer-
copidz, commonly known as spittle-insects, from the fact that they
develop inside of a froth-like substance resembling saliva produced
In summer upon grass and various plants and trees. While none
of these insects have yet become pests, there can be no doubt that
collectively they do considerable harm to plants, as sometimes they
are very abundant and subsist entirely upon their sap.

68 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

In this connection peculiar interest attaches to the contents of 20
stomachs of the pygmy nuthatch from the pine woods of Pacific
Grove, near Monterey, June 24 to July 13. Eighteen of these
stomachs contained remains of Cercopide, and six were filled with —
them. The average for the 18 stomachs is a little more than 76 per-
cent of all the food. They were not identified specifically, but
undoubtedly are one of the several species known to feed upon the
pine. Beetles of various familes form about 12 percent of the food.
There were many weevils, or snout-beetles, in the stomachs, and some
coccinellids, which were the only useful insects found. They amount
to 9.6 percent, which is the largest record for any bird yet examined, |
except the vireos; but as this percentage is based upon the examina-
tion of so few stomachs, it can not be considered as wholly reliable.
Caterpillars amount to 8 percent, and with a few spiders (1 percent)
account for the rest of the animal food.

Vegetable food —The vegetable portion is made up almost entirely
of seeds, of which a majority are those of conifers, as was to be
expected from the habits of the bird.

Two other species of nuthatches, the slender-billed (S7tta ¢._
aculeata) and the red-breasted (Sitta canadensis) occur in California. :
A few stomachs of each have been examined and the contents found —
to agree substantially with the foregoing.

SUMMARY.

In conclusion, it may be said that, like other genera of the Paride,
nuthatches are eminently useful birds. They do not prey upon culti- —
vated crops, eat but few useful insects, and probably are among our _
most efficient conservators of the forest and of the orchard.

PLAIN TIT.

(Beolophus inornatus.)
(Plate V.)

The plain tit, like the rest of its family, is quiet and unobtrusive,
attracting little notice by its voice and movements, and probably is
the most modestly dressed of them all. While it seems to prefer to
hunt on oaks, it does not neglect fruit trees, and often may be seen
flitting about the orchard.

The general character of its food is the same as that of other small
arboreal species. The relative proportions consumed, however, —

1
"

differ somewhat from those taken by other members of the family. |

The plain tit eats a greater proportion of vegetable food than any
other titmouse so far as known, and, what is more remarkable, a |

. . » » . |
large part of this consists of the pulp of fruit.

Bull. 30, Biological Survey, U. S. Dept. of Agriculture PLATE V.

PLAIN TITMOUSE ‘(BAEOLOPHUS INORNATUS).

if NUTHATCHES AND TITMICE. 69

4
2 The following brief account of the food of this bird can be con-
‘sidered only preliminary, as but 76 stomachs were available for exam-
‘ination. These, however, are distributed through the year, so that
every month is represented by at least three. While these results may
‘be modified by future investigation, they probably afford a fair
general idea of the yearly food of the species.

Animal food—Unlike most of the titmice, the plain tit eats less
animal than vegetable food, the proportion being 43 percent of animal
to 57 of vegetable. Examination of a greater number of stomachs
may modify these figures but probably will not reverse them. The
animal food is quite evenly divided among a number of elements, but,
as with the bush tit, bugs (Hemiptera) appear to be the favorite,
mostly eaten during the summer months. These amount to 12
percent of the food. This is a little more than one-fourth of the
amount of Hemiptera eaten by the bush tit. The black olive scale is
@ prominent element of this part of the diet, and forms nearly 5 of
the 12 percent. In the month of August nine stomachs were taken,
and 34 percent of their contents consisted of these scales, while one
tomach was filled with them. The plain tit probably eats this insect
more or less throughout the year, but the hmited number of stomachs
under consideration does not warrant a positive statement. The other
hemipterous food consists of representatives of several families, such
as leaf-hoppers (Jasside), jumping plant-lice (Psyllide), tree-hop-
pers (Membracide), and other remains not identified.

Lepidoptera, represented mostly by caterpillars, are the next

most important ingredient of the food. They amount to nearly 11
ercent, and are mostly eaten during the warm months, though one

taken in March was filled with caterpillars and one moth.

Beetles (Coleoptera) are next in importance in the food, of which
‘they form nearly 7 percent. All are harmful species, but the mem-
bers of one family are especially interesting. The genus Balaninus
s composed of weevils in which the snout attains its greatest length,
and sometimes is as long as the rest of the body. The insects, by
means of this long snout, bore into nuts and acorns, wherein they de-
‘posit eggs, which hatch grubs that eat the nut. The tit finds these
beetles ieee foraging upon the oaks. One stomach contained the
Yemains of 13 of them, another 11, a third 8, and a fourth 7, while
others contained fewer. The plain tit feeds upon mast to some extent,
and it is interesting to note that some of the stomachs which held
remains of Balaninus contained acorn meat also, showing that the
birds found the one while foraging for the other.

Hymenoptera in the shape of ants amount to nearly 4 percent,
while wasps make up the total of this order to about 6 percent.

70 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

Other insects aggregate a little more than 5 percent. Tipulid flies
(daddy-long-legs) were found in several stomachs, as were grass-
hoppers also. One stomach contained the remains of 13 of the latter,
a remarkable number for so small a bird, but the bulk was not great,
and they were probably the débris of several meals. Spiders are-
a very constant article of food, but do not appear in great numbers,
as the average for the year is somewhat less than 1 percent.

Vegetable food—tIn the vegetable food of the plain tit, fruit
amounts to nearly 32 percent. Fruit is a rather surprising item of
the food of this bird, as no one, so far as the writer can learn, has
ever accused it of destroying fruit. The quantity is three times as
much as is eaten by the linnet, and is another illustration of the fact
that in estimating the status of a species the number of individuals
as well as the amount eaten by each individual must be considered.
The fruit consumed appears to be of the larger cultivated varieties,
as no seeds of wild berries were found.

Cherries were identified in a number of stomachs, and pulp of the
larger fruits was abundant. As considerable of this was contained |
im stomachs taken in the late fall and winter months, it is evident |
that it was refuse left on the tree and of no value. Not only does the |
plain tit eat fruit, but to some extent it indulges also in grain. Oats |
~were found in a number of stomachs and constituted nearly 30 per-
cent of the contents of two stomachs taken in January. Grain is
probably not eaten to any considerable extent, however, as the amount |
for the year is but little over 1.5 percent, and oats was the only variety
identified. Leaf galls, seeds of poison oak, weed seeds, unidentifiable
matter and rubbish make up the remainder, 24 percent, of the vege- |
table food. None of these are of much economic importance, except
that the distribution of poison-oak seed is a nuisance.

SUMMARY.

From this somewhat imperfect review of the food of the plain tit |
it is evident that in its present numbers it is useful. The insects it |
eats are practically all harmful and the scales exceedingly so. More- |
over, its habit of foraging in trees enables it to capture some of the
worst enemies of fruit and renders its work in this direction invalu- |
able. On the other hand, it eats quite a large percentage of fruit, |
most of which appears to be of cultivated varieties, and should the
bird ever become as abundant as the linnet now is 1t would undoubt-
edly be a pest. This contingency, however, is extremely unlikely.

CHESTNUT-SIDED CHICKADEE.
(Parus rufescens subspp. )

;
While this bird at present inhabits mountain regions rather than
orchards, still it may not be out of place to give a short digest of our

NUTHATCHES AND TITMICE. fell

knowledge of its food. Fifty-seven stomachs were available for
examination, and these were taken in every month of the year,
except March, April, and May. ‘The food consisted of nearly 65
percent of animal matter and 35 of vegetable.

Animal food—Caterpillars constitute 18 percent of the animal
portion. They were found in nearly every month in which stomachs
were taken, there being a fairly good percentage even in January and
December. The greatest amount, 53 percent, was eaten in August.
Hemiptera, consisting of leaf-hoppers, tree-hoppers, and olive and
other scales, constitute the most important item of food, and amount
to about 25 percent. These were found in all except two winter
months. Wasps were eaten to the extent of 13 percent of the food,
but no ants were found. Beetles amount to less than 2 percent of
the food, but nearly all are noxious; weevils appeared in one stomach.
Fhes and grasshoppers are conspicuous by thei absence, and not
even a trace of one was discovered. Spiders are a very constant ele-
ment of the food of nearly all the titmice. In that of the chestnut-
side they amount to nearly 7 percent for the year, though in August
they constitute nearly 16 percent.

Vegetable food—rThe vegetable portion of the food consists of
fruit pulp 8 percent, seeds nearly 20 percent, and miscellaneous mat-
ter 7 percent. Fruit pulp was found only in a few stomachs taken in
the fall and winter and was probably waste fruit. The seeds eaten
were mostly those of coniferous trees, as was to be expected of a bird
which spends so much of its life in evergreen forests. The miscel-
laneous items of the vegetable food are leaf galls, bits of moss, and
rubbish.

SUMMARY.

The above sketch of the chestnut-sided chickadee, while very
imperfect, suffices to show the general character of its food. A few
stomachs also of the mountain chickadee (Parus gambeli) have been
examined and the contents found to agree in a general way with the
food of others of the group.

WREN TIT.
(Chamaea fasciata subspp.)

This modest, secretive bird, like the eastern chat, 1s more often
heard than seen. At present it does not often live in orchards and gar-
dens, and when it visits these it sticks closely to hedges and the denser
parts of the shrubbery. In general it keeps to its original abiding
places in the dense chaparral of canyons and hillsides. So long as it
is confined chiefly to these situations its food habits will never be of

72 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

more than secondary importance, but as cultivation spreads the bird
will be forced more and more to reside in cultivated districts.

The number of stomachs available for examination is 165, and as
they represent every month except July they afford a fair idea of the
salient features of the bird’s yearly food. Of this 52 percent is
animal matter, insects and spiders, and 48 percent of various vegetable
substanees.

Animal food—The most important item of the animal food con-
sists of ants and wasps (Hymenoptera), which amount to 23 percent
of the whole. This is in strong contrast to the bush tit, whose diet
contains scarcely any of these insects. About half of the Hymenop-
tera are ants. This is exactly what might be expected of a bird of
such terrestrial habits and one so given to lurking under bushes and
about decayed logs and rubbish. The other insects of this order
are small wasps. Beetles, collectively, the next most important item
of food, amount to about 10 percent. The only useful species iden-
tified were a few ladybirds (Coccinellide), and a separate account of
these was kept in order to estimate the harm done by their destrue-
tion. The result shows that the diet of the wren tit contains less than
1 percent of these useful beetles. The remaining beetles belong to
various families, all of them harmful to vegetation. Caterpillars
constitute a little less than 8 percent of the-food, and are a very con-
stant element of the diet. They appear to be eaten at all seasons, but
in the early summer they amount to about one-fourth of the food.
Quite a number of cocoons of tineid moths also were present in the
food.

Bugs (Hemiptera) are eaten to the extent of about 7 percent of the
animal ‘diet. In this respect the wren tit differs from the bush tit,
over 44 percent of whose food is made up of these noxious insects.
In one particular, however, the two birds are alike; scales (Coccide)
are prominent in the food of both. The black olive scale (Satssetia
olew) and the greedy scale (Aspidiotus rapax) were identified in the
stomachs of both birds, and many not specifically identified were
found. ‘The scales were probably obtained from orchards, as it 1s
not likely that these insects have spread to wild plants and forest
trees. As scales are to be had at all seasons they are a constant
element of the food of tits. The remaining animal food, less than
5 percent, is composed of various insects and some spiders. One
stomach contained the legs of a grasshopper and another the remains
of a wood-cricket. These are the only orthopterous remains in any
stomach. Flies (Diptera) were eaten very sparingly. Spiders ap-
peared in a great many stomachs but not in large numbers. They
amount to a little less than 2 percent of the food. In one stomach
were found 26 mites, commonly parasitic on beetles and other insects.
Their hosts had probably been eaten by the tit.

NUTHATCHES AND TITMICE. 13

Vegetable food.—The vegetable contingent of the food, 48 percent,
is made up of various substances, but may be arranged in three cate-
gories—fruit, poison-oak seeds, and other vegetable matter. Fruit,
identified by seeds, pulp, and skins, amounts to a little more than 20
percent of the whole food. Few direct complaints, however, have been
lodged against the wren tit on the score of damaging fruit, and yet
this record is nearly twice that of the linnet—the bird against which
the heaviest charges are made by the orchardist. The reason for
this difference is probably not far to seek. There are undoubtedly
a hundred linnets in California to one wren tit. This again illus-
trates the point before made, that the mischief done by birds usually
results from a superabundance of the individuals of a particular
species, all uniting simultaneously to attack some particular product.
Moreover, the fruit consumed by the wren tit consists largely of wild
varieties—such as elder berries (Sambucus), snow berries (Symphori-
‘rarpos), coffee berries (Rhamnus), twinberries (Lonicera involu-
cerata), and others of a similar character. Seeds of blackberries or
raspberries (Rubus) were found in a few stomachs, but these may
have been either wild or cultivated.

As the seeds of poison oak (Rhus diversiloba) occurred in many
stomachs a separate account of them was kept. From August to
February, inclusive, they form a constant and important element of
the diet. For these seven months they constitute more than one-
fourth of the food, and the average for the year is over 16 percent.
It seems natural enough that the wren tit should eat these seeds, as
they are abundant and easily accessible. The fact is to be deplored,
however, as they are not destroyed in the stomach, but either pass
through or are regurgitated in condition to germinate. The seeds
apparently are eaten for the sake of the rather thin layer of dry white
pulp that surrounds them. No doubt this is very nutritious, as in
winter poison-oak seeds are a common article of diet for many species
of birds. The rest of the vegetable food, over 11 percent, is made up
of a few weed seeds, leaf galls, and rubbish. None of it has special
economic significance.

FOOD OF YOUNG.

Among the stomachs examined were those of a brood of 5 nest-
lings about two weeks old, and therefore nearly ready to leave the
nest. The results are of interest as showing that the wren tit fol-
lows the usual rule and feeds its young entirely on animal food.
The largest item is caterpillars, which amount to 63 percent of the
contents. Spiders, with their cocoons and eggs, are next in import-
ance, with 15.6 percent. Bugs, mostly leaf-hoppers, form 12.2 per-
cent. Beetles of the May-beetle family, with a trace of eggshell,

74 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

make up the remainder, 9.2 percent. One can not fail to notice the
soft nature of most of this food provided for the young. The beetles
are the only exception, and these were the smallest item.

SUMMARY.

In summing up it 1s evident that so far as its natural food is con-
cerned the wren tit does little or no harm, as coccinellid beetles, the
only really useful insects it eats, are consumed very sparingly. Its
vegetable diet presents two points for criticism. It eats a moderate
amount of fruit, and were the bird as abundant as the linnet the harm
it would do in orchards would perhaps more than counterbalance the
‘good. The wren tit, however, naturally is a denizen of dense shrub-
bery, and as this is cleared away for farms and orchards the species
is likely to diminish in numbers rather than increase, unless its habits
radically change. The consumption of the seeds of poison oak is an
unfortunate habit, since it aids in the dissemination of this poisonous
plant, already too common and widespread. All things considered,
the wren tit for the present is to be classed as beneficial.

CALIFORNIA BUSH TIT.
(Psaltriparus minimus californicus. )
(Frontispiece. )

The bush tit is one of the smallest species of the family, and
although its name implies that it 1s partial to bushes, it more often
is seen in large oaks and frequently on the tops of the highest trees.
It shows the same indifference to the presence of man as the rest of
the family, and frequently may be observed scrambling over orchard
trees in search of its favorite food and paying no attention to the
observer. That it does not prey upon fruit to an appreciable degree
appears from the fact that less than 1 percent of its food for the year
consists of fruit. Insects that live on trees, however, constitute
four-fifths of its food, and most’of these are harmful.

In the investigation of the food of this bird 353 stomachs were
examined. They were collected in every month of the year, although
April is represented by but a single one and March by only six. The
ereater number were taken during the growing months, when fruit
and grain abound, and the fact that in these months the bird ate
almost none of these products speaks volumes in its favor. The first
analysis of the food of the year gives nearly 81 percent animal mat-

ter, composed entirely of insects and spiders, to 19 percent of vege-.

table. As the bush tit inhabits the same range during the year,
monthly variations in the kind and proportions of food are only

Diy te

NUTHATCHES AND TITMICE. 75

such as seasonal changes necessitate, and as these do not largely
affect insects, which constitute the great bulk of the bush tit’s food, it
follows that the variation in diet from one month to another is not
great. The smallest quantity of animal food was in March, when
it amounted to 53 percent, but the percentage was almost exactly the
same for November. One stomach taken in April contained nothing
but insects and spiders, and 11 collected in June contained no vege-
table food. Probably examination of a greater number collected in
these months would result differently. While the material available
for the present investigation is not so extensive as could be desired, it
is sufficient to indicate beyond reasonable doubt that the relative pro-
portions of animal and vegetable food in the diet of the bush tit vary
little from season to season.

Animal food —The largest item in the insect portion of this bird’s
food consists of bugs (Hemiptera), which amount to over 44 percent
of the whole. The gnatcatchers are the only birds yet investigated
whose diet 1s made up so largely of this order of insects. Moreover,
the particular familes of Hemiptera so extensively eaten by the bush
tit are the two that are most destructive to the interests of horticul-
ture—namely, the plant-lice (Aphidide), and bark-lice, or scales
(Coccide ). The last amounts to nearly 19 percent of the year’s food,
and are eaten in every month. The greater number are consumed in
July, 46 percent; June follows second in rank, when they constitute
33 percent of the food of that month. The large black olive scale
(Saissetia olew) was identified in 44 stomachs, but other species also
were found. The question is often asked, Does any bird feed upon
the San Jose scale? While the writer is net prepared to give a posi-
tive affirmative answer from direct evidence; there can be no reason-
able doubt that this insect is often eaten by birds. It must be borne
in mind, however, that the so-called San Jose scale is one of the
smaller species, and its distinctive characters are so minute that after
it has been taken into a bird’s stomach, mixed with other food, and
more or less digested, it 1s impossible to determine its identity. It
is easy to ascertain that a pasty mass in a bird’s stomach is composed
of scales partly digested, but to identify the species is quite another
matter. The olive scale and others of its genus, on the other hand,
are so large and their shells are of sch structure that they can often
be identified, at least generically, even from fragments.

While the San Jose scale was not positively determined, another
species of the same genus, the greedy scale (Aspidiotus rapax), was
found in 4 stomachs, and seales not specifically identified were found
in 118. Of a total of 353 stomachs, 158 held scales; several were
entirely filled with them, and in quite a number upwards of 90 per-
cent of their contents consisted of these insects. No other family of
insects was identified in so many stomachs. As it is certain that the

76 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

food contained in a bird’s stomach at a given time is only a fraction
of the daily consumption, we may infer that not many days pass in
the life of a bush tit when it does not eat a considerable number of
scales.

Before leaving the subject it may be well to add a few words on
the economic relations of scale-insects in order that the value of the
work done by the bush tit may be fully appreciated. Mr. Marlatt
says:

The most destructive insect enemies of fruits in California are undoubtedly
the scale insects, few if any other insects, aside from the grape Phylloxera, at
all approaching them in this respect. Of these, the ones of greatest moment
and in the control of which vast sums of money are expended are the black
scale, the red scale, and the San Jose scale. For the olive and citrus plants
the black scale is the most important, and for the deciduous plants the San
Jose scale takes similar rank.¢

When the immense number of bush tits and other birds in Califor-
nia that eat scale insects is considered, it becomes evident that the
ageregate of these pests annually destroyed by them must be enor-
mous. It may be urged that despite the attacks of birds, scales have
caused, and still are causing, much damage to fruit trees, and that the
work of birds alone is inadequate to save the trees from destruction.
This is undoubtedly true, but it must be remembered that the birds
are confronted with abnormal conditions. The great and rapid
. development of the fruit-growing industry on the Pacific coast and
the simultaneous and widespread introduction of several new species
of scales resulted in a sudden increase of these pests, while their ene-
mies, the birds, enjoyed no such opportunities for increase. In time,
no doubt, an equilibrium would have been reached, and birds would
have played an important part in establishing this by exerting a con-
stant and steady check upon the increase of scales. Unaided, how-
ever, their numbers are too few to cope with the insects which, under
favorable conditions of climate and environment and unmolested by
other natural insect enemies, multiply to countless myriads.

The remaining portion of the hemipterous food of the bush tit.
over 31 per cent, is made up of plant-lice, tree-hoppers (Membracide).
leaf-hoppers (Jassida), some jumping plant-lice (Psyllide), and a
considerable number of false chinch bugs (Vysius angustatus), with
a few lace-bugs (Tingitide). Of the plant-lice little need be said.
As pests to vegetation their reputation is world-wide. No part of a
plant is free from attack. They infest leaves, trunk, and roots, and
some of their legions of species prey upon nearly every kind of land
plant. They are a frequent element of the food of the tit, but as their

“Insect control in California, by C. L. Marlatt, U. S. Dept. of Agriculture,
Yearbook, 1896, p. 220.

NUTHATCHES AND TITMICE. 17
bodies are of the softest texture specific identification is not possible.
Many of them, however, were determined to be of the species com-
monly called * woolly aphides, as their bodies are covered with a
white cottony or woolly substance. Aphides were identified in 30
stomachs, but it is probable that they were contained in more, as a
pasty mass that could only be called * hemipterous remains’ was of
frequent occurrence. Leaf-hoppers were found in many stomachs,
and appear to be favorite food. Tree-hoppers also are eaten to a con-
siderable extent, and as their bodies are hard, like those of beetles,
they are more easily recognized than plant-lice. The jumping plant-
hee were found in a few stomachs, but were rather difficult to dis-
tinguish in the conglomeration of plant-lice and other soft-bodied
insects. False chinch bugs were found in a number of stomachs
from the southern part of the State. These, perhaps, were the best
preserved of any of the insects, for in most cases they could be dis-
tinguished individually. Over 50 were taken from one stomach.

Next to the bug family, the favorite food of the bush tits seems to
be beetles. They constitute somewhat over 10 percent of the year’s
food and attain their maximum in September, when they amount to
a little more than 27 percent of the food. The fewest were taken in
December—less than 1 percent—but in all the other months they were
found to a moderate extent except in the one stomach taken in April,
which contained none. Among them were species of the ladybug
family (Coccinellide), which are useful insects, as they are mostly
carnivorous and feed largely upon plant-lice. In order to ascertain
just how much harm the tit does in devouring ladybugs, a separate
account was kept, and it was found that the total amount eaten dur-
ing the year was 2.4 percent of the whole food. Most of these insects
were eaten in September and October, when the consumption
amounted to 11 and 6 percent, respectively. These are the only
decidedly useful insects eaten by the bush tit, and in view of their
small number the subject may be dismissed without further com-
ment. The other beetles taken were largely small leaf-beetles (Chrys-
omelide), all of which are harmful. With them were some small
weevils (Rhynchophora), which feed upon seeds and other parts of
plants, with a few scolytids that burrow under the bark of trees to
their great injury.

Butterflies and moths (Lepidoptera), most of them in the larval
form (caterpillars), are next to beetles in importance in the food of
the bush tit. They are, however, far from being such favorite food
as bugs. The total is a little more than 16 percent. They are fairly
evenly distributed through the year, though in spring and early sum-
mer they are consumed to a somewhat larger extent than in fall and
winter. The greatest consumption was in May, when they aggregated

78 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

nearly 69 percent. Lepidoptera in the adult form do not as a rule
constitute an important part of the diet of birds, but, with the excep-
tion of the flycatchers, the titmice perhaps eat the most. The greater
number consumed by these insects, however, are eaten as larvee—cat-
erpillars. A few, however, are eaten in the pupa state, and here the
bush tit has a good record. In a number of stomachs were remains
of the pup of the codling moth, one of the worst pests to the apple
industry. This insect is protected from the attacks of birds by its
pecular mode of life. It passes the larval stage inside the apple.
The adult moth flies mostly by night and hides during the day.
When the larva is full grown it leaves the apple and seeks a place of
concealment, such as a crevice in the bark of the tree, a crack in the
trunk, or among rubbish on the ground, where it changes to a chrys-
alis. It is in this stage that the insect is most vulnerable to the
attacks of birds, and as the whole family of titmice get most of their
food by searching in just such places as those used for concealment by
the larva, it is not surprising that they find and devour many of them.

The cocoons of certain tineid moths are a very constant, though not
large, component of the food of the bush tit. The larve of many of
the Tineina are leaf-miners, and therefore injurious when attacking
economic plants.

Strangely enough, wasps and ants (Hymenoptera) are nearly absent
from the food of this bird. The total amount for the year is less
than 14 percent. In view of the fact that ants are always crawling
over the trunks and branches of trees, the very places where the tits
feed, it seems strange that so few of them are eaten. Moreover,
plant-lice always have ants in attendance upon them, and when tits
eat so many plant-lice it is rather remarkable that they should not
take some of the ants also, as do the smaller woodpeckers, whose food
habits are in many respects so similar. In 353 stomachs only two
ants were identified, one in the adult and one in the pupal stage, and
these were in separate stomachs. In 17 other stomachs a few frag-
ments of what probably were small wasps were found, which make up
the total of the hymenopterous diet of the bush tit.

The remaining animal food of this bird, about 8 percent, is com-
posed of various insects, such as a few flies, a few bits of grasshoppers,
insects’ eggs not further identified, with a considerable number of
spiders. That the tits should not eat grasshoppers is not surprising,
as these insects do not commonly infest trees where the birds feed,
and as a rule they are rather large game for such small birds. The
great bulk of the 8 percent, however, consists of spiders, which con-
stitute a constant item of food in every month. Quite a number of
pseudoscorpions also were found in the stomachs, but, owing to their
minute size, the percentage is not very noticeable.

NUTHATCHES AND TITMICE, 79

Vegetable food —TVhe vegetable food of the bush tit may be consid-
ered under two categories—fruit and miscellaneous matter. Fruit in
some form was found in stomachs taken in the months from August

to November, inclusive. The average amount eaten in those four
months was a little less than 1 percent. It is represented in the
‘stomachs by pulp and skins, which have not been further identified.
The miscellaneous vegetable matter is composed of a few seeds, gran-
ules of poison oak (hus diversiloba), leaf galls, and rubbish. The
seeds of poison oak are eaten by many birds, and so are distributed
about the country, but, as a rule, they are too large to be swallowed
by the tit, which contents itself with pecking off the wax surrounding
the seed. This is identified in the stomachs by certain woody gran-
ules. A large portion of the vegetable food consists of small galls,
apparently from leaves. They are eaten when first developed, when
young and tender. As each of these probably contained an egg
or grub, it is questionable if they should not be classed as animal
food. The remainder of the vegetable matter is of such a nature that
the only term which really describes it is ‘rubbish.’ It is probable
thatat is mostly taken accidentally along with other food, and perhaps
should not be considered in the food category.

FOOD OF NESTLINGS.

Among the 353 stomachs of the bush tits whose food has been
discussed was one brood of eight nestlings about ten days old. As
these are the only nestlings collected, their food would merit atten-
tion, but examination shows it to be of unusual interest. The vege-
table matter in these stomachs was only three-fourths of 1 percent
and consisted of one seed and some rubbish. The animal matter
comprised, approximately : Beetles 2, wasps 2, bugs 8, caterpillars and
pupe 80, and spiders 7 percent. The point of greatest interest,
however, les in the fact that every one of these stomachs contained
pupe of the codling moth, distributed as follows: Two stomachs
contained 2 each, two contained 3 each, one contained 4, one 7, one 9,
and one 11, making 41 in all, or an average of over 5 to each. The
oak tree in which these birds were found was in a belt of timber
along a creek, and just across the stream was a considerable area of
neglected orchard. It is evident that the parent birds used this
orchard as a foraging ground and did their best toward remedying
the neglect of the owner. As with nestling birds feeding and diges-
tion are almost continuous during the hours of daylight it follows
that 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 (several were seen) along the border of this orchard, and
if, as is probable, the occupants all did as good work as the ones

80 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

recorded it is evident that the birds must exert a powerful restrictive
influence upon the increase of the codling moth, as well as other
insects. :

SUMMARY.

In a résumé of the food of the bush tit the most prominent points
to be considered are the fact that four-fifths of its diet consists of
insects and spiders, nearly all of which are harmful; that more than
half of its animal food is limited to a single order of insects, Hemip-
tera; that it eats the particular families of this order which contain
the worst of insect pests; that the vegetable contingent of the food is
made up almost entirely of substances of no economic value. It is
doubtful if more efficient checks upon the increase of many species
of forest and orchard insects can be found than the titmice and other
closely related species. Bush tits, therefore, are a valuable asset to
the State of California and should be protected and encouraged in
every possible way. :

Following is a list of insects identified in the stomachs of bush tits:

COLEOPTERA.
Crepidodera helxines. SCyMNUS NANUS.
Diachus auratus. Notorus alameda.
Orthoperus sp. Anthicus sp.
Corticaria scissus. Apion vespertinum.
Scymnus marginicollis. Deporaus glastinus.
Scymnus pallens.
HEMIPTERA.
Nysius angustatus. Naissetia olee.
Geocoris bullatus. Aspidiotus rapax.
LEPIDOPTERA.

Carpocapsa pomonella.

The following families of Hemiptera were identified:

Tingitide. Psyllidie.
Capside. Coccidie.
Membracide. Aphididee.
Jasside.

KINGLETS.

Kinglets, like enateatchers and titmice, are small, active birds and
spend most of their lives on trees. So nearly do the feeding habits of
these diminutive arboreal species resemble each other that in winter
it is not unusual to see companies of titmice, kinglets, creepers, and
nuthatches all together, engaged in the same unending search for

KINGLETS. &1

food. When one notices how thoroughly each tree is inspected by
dozens of pairs of keen, prying eyes, he is surprised that any imsects or
their eggs should survive to produce broods.

RUBY-CROWNED KINGLET.
(Regulus calendula.)

The ruby-crowned kinglet is known in California principally as a
winter resident, though in some of the high mountains it remains
through the summer and breeds. Its small size would prevent it
from doing appreciable injury to fruit or grain were any to be had
when it is in the fruit and grain raising regions.

As might be inferred from field observations, its diet consists
almost entirely of insects and their eggs, and the number it destroys
is beyond computation.

In investigating the food of the kinglet 294 stomachs were exam-
ined, all taken in California from September to April, inclusive.
Only 1 stomach was collected in September, 5 in March, and 5 in
April. The other included months are fairly well represented. The
food consisted of 94 percent of animal matter and 6 percent of vege-
table. It was made up of insects, spiders, and pseudoscorpions—
minute creatures resembling microscopic lobsters—fruit, weed seeds,
etc. |

Animal food —The animal food is quite evenly distributed through
the season. The greatest amount, 100 percent, appeared in the first
and last two months, and the least, 79 percent, in January. Hyme-
noptera, in the shape of wasps, and a few ants appear to be the
favorite food, as they aggregate over 32 percent of the whole. The
stomach taken in September contained none of them, but in every
other month they are fairly well represented, and with but little
variation until March, when there is a sudden increase, which con-
tinues in April. This is undoubtedly due to the increased numbers of
these insects following the return of warm, dry weather, for the order
is noted for its fondness for warmth and sunshine. Adverse criti-
cism may be made upon this element of the kinglet’s diet, as flying
Hymenoptera are useful agents in the fertilization of flowers, and
some species of plants are dependent upon them for the performance
of this important function. ‘The parasitic species of this order also
were found to some extent in the food of the kinglet, and unques-
tionably many of these are decidedly useful.

In the food of the kinglet, bugs (Hemiptera) are next in impor-
tance. They constitute nearly 26 percent of the diet, and are found
in greatest quantity in the first months of the bird’s winter stay, in
September and October, but gradually decrease till spring.

9379—No. 30—O7

82 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

The following families of Hemiptera were recognized in the stom-
ach contents: Assassin-bugs (Reduviide), lace-bugs (Tingitide),
leaf-bugs (Capside), leaf-hoppers (Jasside), tree-hoppers (Membra-
cide), jumping plant-hee (Psyllide), plant-lice (Aphidide), and
scale-insects (Coccide). Stink-bugs (Pentatomide), which are the
most universally eaten by birds of any Hemiptera, are entirely want-
ing. Evidently it was not lack of opportunity that prevented the
kinglets from eating the last-named insects, for other birds collected
at the same time and place had partaken of them freely. From the
human point of view it is not strange that birds should reject them,
for to us their odor is vile and their taste nauseous. It will be
noticed that the Hemiptera selected by the kinglet are mostly species
of small size, but happily they are the very ones that are the most
harmful to the interests of man. The tree-hoppers, the leaf-hoppers,
and the jumping plant-lice, when abundant, are pests, and often do
great harm to trees and smaller plants, while the plant-lice and scale-
insects are the worst scourges of the fruit grower—in fact, the preva-
lence of the latter has almost risen to the magnitude of a national
peril. As has been before pointed out, it is these small and seemingly
insignificant birds that most successfully attack and hold in check
these insidious foes of horticulture.

Beetles of various families and species were eaten by the kinglet to
the extent of 13 percent of the season’s food. They belong to species
that are more or less harmful, with the exception of a number of
ladybirds (Coccinellide), which from their habit of feeding on plaut-
lice are eminently useful. The damage done by the destruction of
these useful beetles, however, is small, since they ageregate less
than 2 percent of the whole food. Singularly, nearly all were in
stomachs obtained in February. In this month 8 percent of these
beetles were eaten, while in no other month was so much as 2 percent
taken. Another curious fact is that almost all of these belong to the
genus Scymnus, which is made up of minute black creatures which
one might think would pass unnoticed by birds. On the contrary,
the small and insignificant individuals of this genus appear to be
eaten much oftener than the larger and more showy species. While
the eating of ladybugs by kinglets or other birds is to be deplored,
it must be acknowledged that little harm is done so long as the num-
bers destroyed are as moderate as the above figures imply.

Of the harmful beetles eaten the weevils are perhaps the most
interesting. One stomach contained 20 individuals. which seems
a large meal in view of the size of the bird. Many of the weevils
belong to the family of engravers (Scolytidee), which hve under the
bark of trees and are forest pests. Another beetle found in many
stomachs is Votorus alameda, an insect that lives on trees, but which
does no harm so far as known. One stomach contained the remains of

KINGLETS. 83

100 individuals of this species. Other beetles were found belonging
to about a dozen families, all more or less injurious.

Lepidoptera, both larve (caterpillars) and adult forms (moths
and butterflies) constitute only a small portion of the kinglet’s diet.
They were eaten sparingly in every month but one, but in all aggre-
gate only 3 percent of the whole. While a few caterpillars were eaten,
most of the lepidopterous food consisted of the minute cocoons of
tineid moths, a family of immense size, wide distribution, and destruc-
tive habits. They are largely leaf-miners, and do much damage to
the foliage of fruit and other trees. They are so small that even the
httle kinglet can eat a great many of them at a meal. In only 2
stomachs was anything found that resembled a grasshopper, and in
both the quantity was small and the identification doubtful. Fles
(Diptera) constitute nearly 17 percent of the diet, but are very une-
venly distributed. The greatest amount in one month was in Janu-
ary, 35 percent, all of which was in 7 stomachs collected in the same
place within three days. These 7 stomachs contained an average of
96 percent of dipterous. remains. The birds evidently found a
gathering of flies, probably dormant, and filled themselves almost
exclusively with them. Another series of 4, taken at the same place
in February, also had eaten flies to the extent of over 80 percent of
the food. Spiders and pseudoscorpions amount to nearly 2 percent
of the food, and are taken quite regularly through the season, though
the greater number were eaten in October. These last are curious
minute creatures, the various species of which lve under stones, on
the bark of trees, and in old books.

Vegetable food—The vegetable food of the kinglets may be dis-
cussed under three heads—fruit, weed seeds, and miscellaneous vege-
table matter. Fruit amounts to less than 1 percent of the food, prin-
cipally elderberries (Sambucus). Weed seeds are present to the
extent of a little more than one-tenth of 1 percent, and may therefore
be dismissed without further comment. In the miscellaneous vege-
table food two items include nearly the whole—seeds of poison oak
and leaf galls—which together amount to somewhat more than 4
percent. The eating of the seeds of poison oak is not a commendable
habit in any bird, for the seeds are not destroyed, but after the wax
on the outside is digested are either passed through the intestine or
disgorged, and so these harmful plants are disseminated. In many
of the stomachs certain small round bodies were found that were
diagnosed as ‘ leaf galls... They appear to be galls in the early stage
and are eaten while small and tender.

SUMMARY.

The foregoing discussion of the food of the ruby-crowned kinglet
serves to confirm popular opinion with regard to this bird. As its

84 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

food consists so largely of insects and as these include so small a per-
centage of useful kinds, the kinglet must be classed as one of the
most beneficial of birds. To the horticulturist 1t is especially valu-
able, as nearly all of its food is obtained from trees. With respect to
the persistency with which it forages among trees, it differs conspicu-
ously from such aboreal species as leave the trees in midsummer to
feed upon grasshoppers.
WESTERN GOLDEX-CROWN KINGLET.

‘x

(Regulus satrapa olivaceus.)

Another kinglet, the western golden-crown, occurs sparingly in
winter in some parts of California. Only 9 stomachs have been
examined, but these in the nature of their contents are so similar to
those of the ruby-crown that statements applicable to the latter are
almost certain to apply as well to this species. No vegetable matter
was found in any of the 9 stomachs, and the insects belong to the
same orders and were taken in essentially the same proportions as by
the other species.

Following is a list of beetles which were identified in the stomachs
of the two kinglets:

Coccinella t. californica. - Aphodius rugifrons.
Adalia frigida. Diachus auratus.
Scymnus pallens. Crepidodera helwxines.
Scymnus nebulosus. Hpitrix parvula.
Hesperobanus abbreviatus. Notorus alamede.
Corticaria ferrugined. Anthicus nitidulus.
Throscus sericeus. Apion vespertinum.
Listrus interruptus. Pityophthorus pubipennis.

dseetles were identified as belonging to the following families:

Staphylinide. Scarabzeidee.
Coccinellidze. Chrysomelide.
Monotomidee. Tenebrionidee.
Lathridiide, Anthicidee.

Klateride. Curculionidee.
Throscide. Scolytidee.
Lampyride. Other Rhynchophora.

Malachiidee.
GNATCATCHERS.
(Polioptila spp.)

Gnateatchers are small, active birds of modest colors and unob-
trusive notes. While not conspicuous, they are none the less deserv-
ing of respect and consideration. No complaints have been made
that these busy creatures ever injure fruit or other crops. Their food

GNATCATCHERS. 85

is composed almost exclusively of insects, which they hunt with untir-
ing energy from morning till night. Like the titmice and kinglets,
gnatcatchers are fitted by nature to perform a service which larger
species are unable to accomplish. ‘There are hosts of minute. insects,
individually imsignificant but collectively a pest, that are too small
to be attacked by ordinary birds and are to be combated by man, if at
all, only at great expense. It is toso deal with such pests that they may
not unduly increase that these tiny birds would seem to be especially
designed. Three species of gnateatchers live within the limits of the
State of Califorma. Two of them, Polioptila plumbea and P. cali-
fornica, are confined to the southern part, while the third, ?. carulea
obscura, occurs locally throughout the State. The material for a
thorough discussion of the food of these birds is unfortunately not at
hand, but there is enough to show conclusively the nature of the
work they are doing, and to enable us to assign them their proper rank
among the friends and helpers of mankind.

The food of the gnatcatchers is remarkably constant in character
throughout the year, varying but httle from month to month. It is
probable that these birds have a preference for a certain diet, and
search till they find it.

Only 30 stomachs of P. c. obsewra and the same number of P. cali-
fornica have been examined, and their contents were so similar that
they may be treated as from a single species.

Vegetable food—Of the 60 stomachs three only contained any
vegetable food whatever, and in only one did it amount to a respect-
able percentage. This one held 92 percent of seeds of some species
of Rhus; another contained 8 percent of unknown seeds, and the
third a few bits of rubbish, which amounted to only 2 percent of
the whole contents. The total vegetable matter in the 60 stomachs
ageregated less than 2 percent of the entire food.

Animal food.—The remainder of the food, over 98 percent, is made
up of beetles, wasps, bugs, and caterpillars, with a few flies, grass-
hoppers, and spiders. Bugs (Hemiptera) constitute more than half
of the whole food, 64 percent. These belong to the families of stink-
bugs (Pentatomide:), shield-bugs (Scutelleride), tree-hoppers (Mem-
bracide), leaf-hoppers (Jasside), and leaf-bugs (Capside), with
perhaps traces of several others. In one stomach were 20 percent of
black olive scales (Saissetia olew). All of these are harmful to trees
and other plants. Wasps and a few ants (Hymenoptera) are next
in importance as an element of the gnatcatcher’s food, and amount
to over 16 percent of the whole. These birds, like the flycatchers,
take much of their prey on the wing, and it is probable that wasps
and small bees are captured in this way. Beetles of several families
were eaten to the extent of over 7 percent of the food, but no decided

86 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

preference for any particular kind is indicated. The only decidedly
useful insects in any of the stomachs were 2 ladybird beetles (Cov-
cinella t. californica), which had been eaten by P. californica. As
this beetle is very abundant in ‘California it is not surprising that
birds should eat a few of them. Caterpillars amount to about 5
percent of the diet of the gnatcatchers. Apparently they are not a
favorite food. Other insects, such as a few flies and grasshoppers,
with some spiders, aggregate 6 percent, and probably are makeshifts,
eaten when nothing more palatable is at hand.

SUMMARY.

While the foregoing discussion of the food of the gnatcatchers is
based upon a small amount of material, the agreement of the evidence
renders it probable that a much larger quantity would not greatly
change the results. This evidence’ confirms what has long been sus-
pected, that the gnatcatchers are doing a useful work and should be
carefully protected. |

RUSSET-BACK THRUSH.

(Hylocichla ustulata. )

The russet-back thrush abounds in the region about San Francisco
Bay and other parts of the humid coast belt. It remains in this part
of the State from April to November,, inclusive, and then moves
farther south for the winter. Its favorite haunts are the bushes and
trees bordering streams, and in these it nests and rears its young.

While the thrush is very fond of fruit its partiality for banks of
streams keeps it from frequenting orchards when they are far from
water. It is most troublesome during the cherry season, at the time
when the young are in the nest. It might be inferred from this that
the nestlings are fed on fruit, but such is not the case to any notice-
able extent. The parent birds eat the fruit themselves, while the
young, as is usual with nestlings, are fed mostly upon insects. The
old birds eat some fruit throughout the season, but do not seem to
attract much attention by their depredations on prunes and the later
fruits. As the thrush, unlike the linnet, is one of the so-called ‘ soft-
billed ’ birds, its attacks on fruit are limited to the thin-skinned varie-
ties. Probably it can peck holes in ripe cherries; still it is as“often
seen on the ground pecking at fallen fruit as attacking the fruit on
the trees. It thus probably confines its depredations upon the later
fruits to such as have already been broken into by linnets or other
stout-billed birds.

Be this as it may, the thrush is an efficient destroyer of insects,
and during the eight months of its sojourn in the fruit region a
little more than half of its food consists of harmful insects. In the

GNATCATCHERS, 87

investigation of this bird’s diet 157 stomachs were examined. The
birds came from various points about San Francisco Bay, and on the
coast from Monterey to Santa Cruz, except one migrant which was
taken in the southern part of the State. Only 6 stomachs were
collected in April, 5 in October, and 7 in November. In the remain-
ing four months 139 were taken, and as they are fairly evenly dis-
tributed the results for these months may be looked upon as reason-
ably reliable. [Examination of the food shows 52 percent of animal
matter to 48 percent of vegetable.

Animal food.—The greatest quantity of animal food was eaten in
the first and last parts of the season—in fact, the six stomachs col-
lected in April contained no trace of vegetable food. The animal
matter decreases in each month up to September, in which month
only 17 percent was eaten. From this month it increases, and ends
with 62 percent in November. Too much reliance should not be
placed upon the latter figures, as they were obtained from entirely
too few stomachs, and are likely to be modified by the examination of
more material. The animal portion of the food is mostly insects and
spiders, with some earthworms and sowbugs (Oniscus).

Jseful beetles (Carabide, Coccinellide, etc.) amount to less than
3 percent of the food of the year. Most of them are eaten at the
beginning of the season before other insects are common. Other
beetles, all more or less harmful, constitute 11 percent of the year’s
food, and are eaten chiefly the first of the season, decreasing toward
fall but with a shght increase at the end. They are pretty evenly
distributed among the more common families, and no decided prefer-
ence is evident for any. It is probable that the thrush eats any
beetles that come in its way, and does not make special effort to find
a particular kind.

Caterpillars form somewhat more than 8 percent of the food, and
while they are eaten in every month of the thrush’s stay, they are
taken much more freely previous to August. During and after that
month they cease to be an important element of the diet. The average
consumption of the first four months of the season is a trifle over 15
percent. Ants and wasps (Hymenoptera), bugs (Hemiptera), flies
(Diptera), and grasshoppers (Orthoptera) are eaten by the thrush,
although little preference is shown for any one of these except for
Hymenoptera in the shape of ants. These are eaten with remarkable
regularity throughout the season, and form about 16 percent of the
food. This is the largest insect element in the food of the thrush,
‘and the regularity with which ants are eaten would seem to indicate
that they are highly esteemed and especially sought for.

While these insects do not often make themselves pests by directly
attacking fruits and crops, they aid and abet the work of other insects
in a way which renders them as bad as the worst of those directly

88 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

attacking crops. Their habit of caring for and protecting plant-lice
is too well known to require extended comment. They take possession
also of the empty burrows of wood-boring larve and extend these
galleries still farther into sound timber. They often throw up
mounds on lawns and in gardens, where it is almost impossible to ex-
terminate them. In houses they frequently are an intolerable nui-
sance, infesting the pantry and spoiling food. The species that are
not offensive in these various ways are mostly of a neutral character
in their economic relations, and their destruction by birds does
neither good nor harm.

Hymenoptera, other than ants (mostly wasps), bugs, flies, and
grasshoppers, with some spiders, amount altogether to 12 percent of
the year’s food, and appear very regularly through the season. Grass-
hoppers, however, are near being conspicuous by their absence, as re-
mains were found in only 4 of the 157 stomachs. This is rather re-
markable for a bird whose habits are so terrestrial as those of the
thrush. The majority of ground-feeding birds and many arboreal
species feed largely upon grasshoppers. In fact, there is no order
of insects for which insectivorous birds in general show such a decideci
preference. The spiders eaten by the thrush belong largely to the
order Phalangida, commonly known as ‘harvest men’ or ‘ daddy-
Jong-legs.’

Vegetable food.—The vegetable food of the thrush consists prac-
tically of fruit either wild or cultivated. A few weed seeds were
found in several stomachs, but they amount to only a trace. It is
probable that the greatest harm done by this bird is to the cherry
crop, though undoubtedly it eats the later fruits to some extent. In
May and June the fruit eaten reaches 41 and 38 percent, respectively,
and this probably represents the greatest injury which the bird does,
as most of the fruit was the pulp and skins of cherries. From June
onward seeds of blackberries and raspberries (Rubus) were fre-
quently found in stomachs, but as these berries are both wild and cul-
tivated it is impossible to tell how much came from gardens. One
stomach taken in early June contained seeds of the twin berry (Loni-
cera involucrata). Seeds of the elderberry (Sambucus) were abun-
dant in stomachs taken in the late summer and fall, and indicate that
this fruit constitutes a very considerable portion of the vegetable diet
of the thrush at that season. Besides these were seeds of the pepper
tree, of Solanum (a weed), and one stomach contained fruit of the
coffee berry (Rhamnus californica). A few seeds of poison oak were
found in two or three stomachs. The greatest amount of fruit was
eaten in September, and reaches a total of over 80 percent, but as the
number of stomachs is not as great as could be desired the result can
searcely be considered final. Moreover, a large part of this was wild
fruit.

GNATCATCHERS. 84
FOOD OF YOUNG.

Among the stomachs examined were those of 25 nestlings taken in
June and July. Their approximate ages and dates of capture are
given in the following table: |
Age

(approxi-|
mate).

Date of
taking.

Brood Number of
No. young.

2] June
Zz 8 | June
3 ee 4)/ June 1]
AP) Threeres .\ 14} June ]
5 1} July 2
6 3 | July 2
7 I 1

7 1

June
July

Taking the collection as a whole their stomachs contained 92.6 per-
cent animal matter to 7.4 percent of vegetable. Caterpillars aggre-
gate nearly 27 percent and were found in every stomach but 7. No
other element was so abundant. Beetles collectively are next in
importance, with 22 percent. Of these the useful Carabidee amount to
7.7 percent and are very irregularly distributed. All the remain-
der are more or less harmful species. Bugs (Hemiptera) aggregate
13.8 percent. Five families of these were identified, viz., stink-bugs,
leaf-hoppers, tree-hoppers, shield-bugs, and cicadas. Ants and a few
other Hymenoptera amount to 12 percent, and spiders to exactly the
same. These last were mostly harvest-men or daddy-long-legs (Pha-
langide). A few miscellaneous insects amount to 6 percent, which
males up the whole of the animal food. Four stomachs of the russet-
back contained remains of grasshoppers and three of these were nest-
lings. Carabid beetles were eaten by the young birds to the extent of
7.7 percent, which is more than three times the amount eaten by the
adults. This is rather singular, for most of these insects are very
hard-shelled and not at all the kind of food usually selected for young
birds. Another interesting point is that all were contained in the
stomachs of broods Nos. 2, 4, and 5. None of the other nestlings’
stomachs held a trace of them.

The vegetable food amounts to 6.8 percent of fruit, with less than
1 percent of two or three other things. The fruit was nearly all
either blackberries or raspberries, which were found in 11 stomachs,
with twin berries in 1. One seed of filaree and some rubbish made up
the rest of the vegetable food.

While the above affords a general idea of the food of these nest-
lings as a whole, there are some differences in the food of the different
broods, which may be worthy of notice. The stomachs of broods Nos.
1,2, and 6 contained no vegetable matter, as was the case with one each

of broods 3 and 5. Broods 4, 7, and 8 had all eaten vegetable food,

90 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

but more than four-fifths of the whole was contained in the stomachs
of broods 7 and 8. The average percentage for these two broods was
over 22 percent, or about three times that of the whole. Again,
Hemiptera, in the stomachs of broods Nos. 1 to 7, inclusive, amount
to an average of less than 4 percent, but in brood No. 8 the average
per stomach is over 53 percent of the food. Spiders were found in
nearly every stomach of broods 1 to 4, while the other four broods
contained very few. These facts indicate that birds exercise com-
paratively little choice as to the exact nature of their food, but take
that which is nearest to hand. With a brood of hungry young inces-
santly clamoring for supplies little opportunity is afforded the busy
parents to select precisely the kind of insects best adapted to the
wants of the young. Nature teaches that insect food and not vege-
table is needed and the gaping mouths are filled with the nearest
obtainable supply.

In addition to the examination of stomachs of nestling thrushes
field observations were made on the feeding of the young by the par-
ent birds. Two nests of this species in the town of Hayward, Cal.,
were observed during several days in June and July, 1901. Each
nest was watched for two one-hour periods on as many days as pos-
sible, and the number of times that the young were fed was carefully
noted.

It may be said, to begin with, that the stomachs of young birds are
kept constantly full during the hours of daylight.

Nest No. 1 was situated on a tree on the bank of a small creek on
the edge of an orchard. When first observed, there were three young
in the nest, apparently about five days old. This nest was watched
for one hour from 9.40 a. m. on June 30, and the young were fed
six times, but, as both parent birds came to the nest once with food
in their beaks and went away without feeding the young, it is prob-
able that they were not quite satisfied as to the intentions of the
observer. At 4.25 p.m. of the same day another hour was spent in
watching the nest, and the young were fed 11 times. On July 1,
ss ae at 8.30 a. m., 7 feedings occurred in one hour. This nest

ras not again watched until July 3 at 840 a. m., when the young
were fed 8 times during the hour. In the afternoon of the same day,
beginning at 3 o’clock, 12 feedings were observed in one hour. The
last observation of this nest was made on July 5, beginning at 9 a. m.
In an hour 13 visits with food were noted. In the case of this brood
there were 57 feedings in six hours, or an average of 94 feedings per
hour. As there were three young, each one must have been fed a » hit-
tle more than three times per hour.

Nest No. 2 also contained three young, but they were only about
2 days old when first visited. The first observation was on June 380,

GNATCATCHERS, 9]

at 3.20 p. m., and the following hour the young were fed 8 times,
and as the weather was cold the mother bird spent a number of min-
utes on the nest warming the nestlings. On July 1 another hour was
spent in watching the nest, beginning at 9.30 a. m., and only 4 feed-
ings were observed. It was, however, a cold, windy morning, and
one or other of the parent birds remained on the nest all the time,
leaving only when the mate brought food and took its turn brooding.
The necessity for keeping the nestlings warm evidently prevented the
parents from feeding them as often as customary. On the morning
of July 3, although the weather was still rather cool, the birds
seemed to be making up for the scanty feeding of the previous days,
for they were observed to feed the young 15 times in an hour, begin-
ning at 9.40 a. m., although they still took turns in warming the
young for a few minutes at atime. In the afternoon of the same day,
beginning at 4 o'clock, 8 feedings were noted in an hour. On July 5,
beginning at 10 a. m., the parents were seen to feed the nestlings no
fewer than 18 times, although one of them spent several minutes
upon the nest three times during the hour. In the afternoon of that
day 11 feedings were noted, in the hour beginning at 3.30, and 3
times one of the parents brooded the young, remaining once for six
minutes. The next observation on this nest was made on July 6,
during the hour from 7.50 a. m., and 12 feedings were noted. On
July 7 the last observation was made, beginning at 3.20 p. m., and 11
feedings were noted. In this case there were 87 feedings in eight
hours, or an average of nearly 11 per hour.

Considering both nests together, as each had the same number of
young, we have 144 feedings in fourteen hours. Now at this time of
year there are just about fourteen hours of available daylight, so that
144 feedings may be considered as an average day’s work for a pair
of parent birds, and as signifying the destruction of at least 144
insects, probably several times that number. Each of the three
young must have been fed 48 times, which means that each stomach
was filled to its full capacity several times during the day, another
illustration of the fact that the digestion and assimilation of birds,
especially of young ones, is constant and very rapid. This is further
shown by the fact that when attempts have been made to raise young
birds the experiments in most cases have failed because the nestlings
were not fed often enough and actually starved to death. Young
birds thrive best when fed a small quantity of food at short intervals
rather than greater quantities at longer periods.

SUMMARY.

From the foregoing it appears that although this thrush eats con-
siderable fruit it is not a pest to the fruit grower. Cherries seem to

92 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

be the only kind eaten to any considerable extent, and in the later
summer wild fruit forms a large part of its vegetable diet. This
thrush does not aid in the destruction of the seeds of noxious weeds.

In its insect diet the russet-back thrush is almost wholly beneficial,
as it eats but few predaceous beetles or other useful insects. As
young thrushes are fed almost exclusively upon insects, and as they
eat almost continuously from morning till mght, they must destroy
an enormous number of these harmful creatures. From our present
knowledge of its food and general habits, the russet-back thrush must
be considered as one of our positively beneficial birds.

HERMIT THRUSH.

(Hylocichla guttata.)

The hermit thrush occurs in the valley and foothill parts of Caii-
fornia only as a winter visitant. Thus it can destroy no fruit, except
perhaps olives, and thus far no complaints have been made against
the species in this respect. Although the bird has not yet attracted
attention by depredations upon fruit, it may be well, nevertheless,
to glance at its food habits as indicated by the contents of 68 stomachs.
These were mostly taken in or about the Bay region, while a few
came from the southern part of the State. Examination of the con-
tents of these stomachs shows animal matter to’ the extent of 56
percent and vegetable 44 percent. The proportion of the two
elements varies little in the different months.

Animal food——Hymenoptera, mostly ants, constitute the largest
item of the insect food. They amount to 24 percent, and appear to
be eaten regularly in every month. This record is better than that
of the russet-back. Caterpillars come next in importance, and form
10 percent of the food. They seem to be eaten rather more freely
in February and March than in other months, though they are taken
at all times of year. Predatory beetles (Carabide) are noticeable by
their absence, as only a few remains of them appear. Beetles of other
families, all harmful species, ferm 11 percent of the food. Weevils,
or snout-beetles (Rhynchophora), constitute more than two-thirds
of these, which would seem to indicate that they are a favorite food.
When we consider that the carabids live on the ground, and are the
most abundant and most easily obtained of any of the common
beetles, and note how few of them the hermit thrush eats, while on
the other hand it eats many snout-beetles, which, living to a great
extent on trees, are generally much more difficult to find, we are
forced to the conclusion that the latter are a preferred food, and that
they are purposely sought for. Other insects, with some spiders and
a few miscellaneous articles of diet (Oniscus), amount to about 12

WESTERN ROBIN. 93

percent. As in the case of the russet-back thrush, one stomach of the
hermit contained the bones of a salamander.

Vegetable food—The vegetable food is made up of two principal
components—fruit and seeds. The former amounts -to 29 percent
of the whole, and is composed of wild species, or of old fruit left on
trees and vines. A few stomachs contained seeds of raspberries,
which, of course, must have been old, dried-up fruit. Seeds of the
pepper tree and mistletoe were the most abundant and, with some
unidentifiable pulp and skins, make up the complement of fruit. The
hermit thrush eats more seeds than the russet-back, but does not
stand high as.a weed destroyer. Seeds of all kinds amount to 14
percent of the food, but only a few are usually reckoned as weed seeds.
The most abundant seed was poison oak (Rhus diversiloba), which
was found in a number of stomachs. While this plant is not usually
classed among weeds, it is really a weed of the worst description,
since it is out of place no matter where it is. It is unfortunate that
birds in eating the seeds of this plant do not destroy them, but only
aid in their dissemination.

SUMMARY.

On the whole, the food of the hermit thrush is remarkably free
from useful products, destruction of which is a loss to mankind. The
worst that can be said of the bird is that it eats and scatters the seed
of poison oak, but it does not do this to a marked degree.

WESTERN ROBIN.
(Merula migratoria propinqgua.)

In most of the valleys of California the robin is a winter resident
only, and would be of little economic importance did it not possess
a voracious appetite, the satisfaction of which occasionally leads to
lamentable results. Of its summer food we know almost nothing,
except what may be inferred from its lst of edibles while in the
valleys, and by comparison with the diet of its eastern relative. The
two birds are so nearly alike that probably in the same environment
they would eat practically the same things.

In investigating the food of the western robin 74 stomachs were
examined. They were taken in every month from September to —
June, inclusive, except May. This number is entirely too small to be
used as a basis for final conclusions, but it suffices to give a hint as to
the differences, if any there be, between the food of the eastern and
western races. Only one stomach was taken in each of the months of
September, October, and June. The others are well distributed
through the remaining months. Discarding returns from the three

94 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

months mentioned, 71 stomachs remain, from which a fairly reliable
idea of the winter food of the robin in California may be obtained.

In the first examination we find 40 percent of animal food to.60
of vegetable. The food of eastern robins for the whole year con-
tains 42 percent of animal matter to 58 percent of vegetable, and
during the six months beginning on November 1 the amounts are:
Animal 35 percent and vegetable 65 percent. If, however, our study
is restricted to the three winter months, we find that the eastern robin
eats 18 percent of animal food and 82 percent of vegetable, while
for the same period the western one consumes 22 percent animal
and 78 percent vegetable. These comparisons do not indicate essen-
tial differences in the food of the two birds. The western bird eats
more insects during the winter months because on the west coast
insects are more abundant and more easily obtained at that season
than in the East. Confining attention, however, to the six months
beginning with November, the eastern bird eats a greater percentage
of insects. It is almost certain that if the material were at hand to
illustrate the food of the western robin during the remainder of
the year, the bird would be found to eat a much larger percentage
of insects than in the six months covered by this investigation.

Animal food—Beetles of various famihes are the largest item of
animal food. The greater number were eaten in April, when they
amount to over 54 percent of the whole food for the month. They
were distributed among several families, but the most conspicuous
were the snout-beetles, or weevils, which aggregated 25 percent.
This is a favorable showing for the robin, for these beetles are among
the most harmful insects with which the fruit growers and farmers
have to contend. The average percentage of beetles for the whole
six months is about 13 percent of the food. Caterpillars are next in
order of abundance and amount to over 4+ percent. The remainder of
the animal food is made up of various insects, of which no order
claims preeminence, and of a few angleworms.

Vegetable food—rThe bulk of the vegetable food from November
onward is cultivated fruit. After this month it gradually falls off,
and very little was found in stomachs collected in March and April.
With the exception of olives, the bird can obtain no fruit of value
after the Ist of November, and as olives were not identified in any of
the stomachs it is probable that most of the fruit consumed was
worthless, having been left after the crop was gathered. The follow-
ing fruits were identified: Grapes in 5 stomachs, figs in 3, prunes in
2, pear, apple, and blackberries in 1 each. Of wild fruit, pepper ber-
ries were found in 17 stomachs, mistletoe berries in 2, and fruit not
positively identified in 11, Pepper berries evidently are the favorite,
since not only were they found in the greater number of stomachs,
but 1 stomach contained 24 and another 28 of these berries. Two

WESTERN ROBIN. 95

stomachs contained wheat and 3 had weed seeds, but dry seeds are evi-
dently not favorite food with the robin.

Destruction of olives —From the foregomg the robin would not
appear to do much damage, or at least not more than is amply paid
for by the insects it destroys. But, unfortunately, more is to be said
about its food habits, which does not redound so much to its credit.
In certain years when their customary food is scarce, robins appear
in the valleys in immense numbers, and wherever there are olives
they eat them so eagerly and persistently that the loss is often serious
and occasionally disastrous. Sometimes, indeed, it is only by the
most strenuous efforts, with considerable outlay of labor and money,
that any part of the crop can be saved. Fortunately, such extensive

damage is not done every year, although here and there the olive

crop may suffer.

There is probably no more striking example of exceptional and
intermittent damage to fruit by birds than an instance which occurred
in the winter of 1900-1901. In that year the olive orchards in
rarious parts of California were invaded by immense numbers of
robins, which ate the fruit and in some instances destroyed the whole
crop. In orchards where persistent effort was made to destroy and
drive them away they still ruined from one-fourth to one-half of the
yield. Olive orchards in Santa Clara Valley especially were afflicted.
Mr. Paul Masson, who owns two orchards near Saratoga, as quoted
by the San Jose Mercury of January 17, 1901, says:

In my largest orchard of about 500 trees adjoining a larger orchard of about
50 acres on the El Quito farm, which is owned by E. E. Goodrich, are thousands
of robins, which are destroying all the fruit on the trees. About two months
ago I estimated that my trees would yield about 4 tons of olives, but Sunday,
when I visited my orchard, I found the fruit would not be worth picking.

I killed some of the robins, and upon examination found as many as five or
six whole olives in the crop of each bird. Besides those which the bird had
swallowed whole, many olives are pecked so that they are spoiled for market.
Sunday there were not less than 50,000 robins on my place, and they are equally
as plentiful on El Quito farm.

Mr. Edward E. Goodrich, the owner of El Quito farm and olive
orchard, quoted by the same authority, says:

The so-called robin is a destructive pest to an olive orchard. <A crop can not
be saved when the migration of the robin corresponds exactly with the maturity
of the olive, as it does this year, except by immediate picking, which is prac-
tically impossible, or by shooting so constantly as to prevent steady consump-
tion. * * * In 1898 my crop was 130 tons, and should -have made about
4,000 gallons of oil. Owing to the lack of rain the result was about 2,750 gal-
lons, of the value of $11,000. Now, that crop could have been wiped: out in ten
days by robins if they hid been here as they were this season and no shooting
had been done. So far as my foreman could estimate, before the birds
descended upon the place, he placed the crop at a probable 3,000 gallons, which
means when sold from $12,000 to $16,000, according to prices, and that would
have been utterly destroyed but for the constant shooting the last ten days.

96 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

As it was, Mr. Goodrich placed his loss on the olive crop through
the devastations of the robins at 25 percent of the whole, or about
$5,000, while his foreman, in an interview with the writer, estimated
the loss at 50 percent. He stated also that robins were so numerous
that he killed 7 in a tree at a single shot.

The San Jose Mercury also states:

A representative of the Mercury visited the E] Quito olive orchard to see what
the facts were in this matter. He found a force of men picking the fruit as
rapidly as possible, and he also saw thousands upon thousands of rebins doing
the same thing. On his way out he occasionally saw a single bird on the fence
or in a prune tree, but when he reached El Quito the sky was streaked with
robins flitting about and having a gala time of it. Men were scattered about
through the orchard with guns, and every few minutes the report of one of
these would set the robins to flying, but in an instant they would settle down
again and resume their feast.

Hon. Ellwood Cooper, of Santa Barbara, one of the largest olive
growers on the Pacific coast, in a letter dated January 25, 1901, says:

The robin is a terrible pest to olives. The birds do not always appear to come
to the coast. My first experience was some fifteen years ago. The olives were
late inripening. I wasas lateas March making oil. The robins appeared to come
in by the thousands. My last orchard that year was about one-half mile in length.
The pickers were at.one end. I had a man with a gun at the other, but they
would attack the middle, and when the gunner would reach them they would
fly to the end he left. This year they have been particularly bad. My boys
reported that the birds, mostly robins, picked more olives than they could. ,The
foreman of the pickers told me that he had knocked from a tree one-quarter of
a sack and went to dinner; when he returned not an olive was on the ground.
I know that on the ground in one orchard where the rain had caused to fall as
many olives as would fill a bushel basket, in a week not one would be seen. The
robins do not seem to be able to pick the olives so rapidly from the trees, but
peck at those that are commencing to dry, knock them to the ground, then get
them. The birds at this writing are in all my orchards by the thousands. They
do not appear every year. It has been my theory that the native berries in the
Sierra Some years are not in sufficient quantities for food.

In the last sentence Mr. Cooper has probably suggested the true
cause of the trouble. There is a crop of olives every year and the
number of robins fluctuates little, but they rarely attack olives because
usually their native food abounds. Where this fails the hungry
birds shift about until they find a substitute.

SUMMARY.

With the exception of such sporadic cases as the above, the food
habits of the robin are for the most part of a beneficial, or at least
harmless, character. In the eastern part of the country very little
damage by the robin is reported, though it is one of the most abundant
species. This is probably largely owing to the plentifulness of wild
fruits throughout the season. The trouble in California is that the
robins from an extensive region concentrate into a comparatively

WESTERN BLUEBIRD. . 97

small area and, finding an abundant supply of palatable food, feed
upon olives to the exclusion of all other food.
_ Were the hills and canyons of California as well supphed with wild
berries as are the corresponding places in the Appalachian region,
it is doubtful if such devastations of the olive crop would ever occur.
Since failure of the natural food supply of the robin is only occa-
sional and can not be anticipated in advance, no direct safeguards
against the bird’s inroads are possible, though the planting of pepper
and other berry-bearing trees about the orchards would materially
aid in protecting the olive crop. The prompt and unsparing use
of the shotgun when the emergency occurs, even though it seems to be
the only practicable method to save the crop, is much to be deprecated,
since the destruction of robins, which in the main are useful birds,
is a loss to the community.

WESTERN BLUEBIRD.
(Sialia mexricanus occidentalis. )

The western bluebird has the same gentle, quiet demeanor that
characterizes its relative of the Eastern States. It has not yet, per-
haps, become quite so domestic as that species, but still is much in-
clined to frequent orchards and the vicinity of farm buildings.
While the eastern bluebird usually nests either in a hole of an orchard
tree or in the box specially provided for its use, the western species
has not yet fully abandoned its habit of utilizing forest trees as nest-
ing sites, and often may be found in lonely canyons or among the
hills far from the abodes of man. The orchards of California
as yet are hardly old enough to offer many hollow trees as nesting
places of the kind so dear to the heart of our gentle friend. There
is no reasonable doubt that in time the western species will become
as domestic as the eastern one. A nest was found by the writer in a
hollow tree in the home orchard of a ranch, only a few rods from the
house. It contained six young, which would indicate that the bird
is a prolific breeder, in this respect also resembling the eastern
species.

The western bluebird is less migratory than the eastern and does
not entirely desert the United States in winter; so its good work is
continuous. As insects are active in California in every month the
bird is able to support life even if there is no other food. More-
over, the insects eaten in winter count more in the reduction of these
pests than do those taken after the spring broods are out. Insects
that live through the winter are the stock by which the species is
perpetuated, and the destruction of a few at this time is equivalent
to the death in summer of hundreds or thousands.

9379—No. 30—0i——_T

98 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

The food of the bluebird consists of elements whose consumption
is almost wholly a benefit to the farmer. Four-fifths of it is insects;
only a small portion of these are useful, and these to a limited extent.

In the investigation of the food of the bluebird 187 stomachs were
examined. This number is not so large as could be desired, and,
moreover, was rather irregularly distributed over the year. Only
one stomach was obtained in May, and only one in April, while the
number for several other months are too few. Geographically they
fairly well represent the fruit-growing regions of the State from as
far south as San Bernardino northward to Santa Rosa. The food
found in the stomachs consists of animal matter, 82 percent; vege-
table, 18 percent.

Animal food—Of the animal portion a little less than 12 percent
consists of predaceous beetles (Carabidee), which are usually reck-
oned as useful. There are, however, many exceptions to this rule,
and since most of the species of this family are wonderfully abun-
dant it is not probable that the bluebird does much harm by eating
them. It is believed, moreover, that this record of Carabide is above
the normal, for the one bird taken in April had eaten 90 percent of
these beetles, thereby raising the average of the whole. In August,
on the other hand, not one of the five birds examined had eaten a
carabid. Had these months been omitted from the reckoning the
average would have been reduced to about one-third of the present
figure, which is probably much nearer the truth.

Other beetles amount to over 17 percent of the food, and were
distributed among about a dozen families, all of them harmful, except
three or four ladybirds (Coccinellide), which are useful.

Caterpillars evidently are a favorite food, and probably are eaten
in every month, though evidence is wanting for April and May.
They amount to over 17 percent of the year’s food. Few of these
insects are eaten in spring and early summer, many in fall and winter.
As practically all caterpillars are harmful, this item of diet counts
entirely in the bird’s favor.

Grasshoppers and crickets, mostly the former, were eaten in every
month except April, but a greater number of stomachs would prob-
ably give a different result. They amount to a little less than 24
percent of the year’s food. They appear in the stomachs of western
birds at a somewhat earlier date than in those of eastern species.
In the Atlantic and Central States, August is preeminently the season
of grasshoppers, and in that month they constitute the principal
article of diet of many species of birds. The western bluebird eats
grasshoppers in March to the extent of about 11 percent of its food.
In June they amount to over 38 percent, and in July reach a maximum
of nearly 49 percent, or nearly half of all that it eats. In September
they amount to 40 percent, but decrease rapidly from that time.

WESTERN BLUEBIRD. ; QQ

Bees and wasps (Hymenoptera) are not largely eaten by the blue-
bird, and flies scarcely at all, as the aggregate for the year amounts
to only four-tenths of 1 percent. | :

In the summer bugs (Hemiptera) are eaten to a moderate extent.
The species belong mostly to the family of ‘soldier bugs’ (Penta-
tomidx) or, as they are sometimes called, ‘ stink-bugs, for they have
a vile odor and when taken into the mouth with a berry are not agree-
able to human taste. The total percentage of wasps, flies, bugs, and a
few other insects is a little less than 10 percent of the whole food.

Spiders are eaten to some extent throughout the year, but never in
great numbers. The greatest number are taken in February, about 6
percent. The total average for the year is 2 percent. One stomach
contained the lingual ribbon of a snail.

Vegetable food —The bluebird asks practically nothing of man in
the way of vegetable food. It is evident that it is not a lover of seeds,
as is the linnet, and with abundance of them at hand, eats few or none.
In 2 stomachs several small unknown seeds were found, which may
have been swallowed. accidentally. Not a kernel of grain had been
eaten. Fruit constitutes nearly the whole vegetable portion of the
food, and was distributed as follows: Elderberries (Sambucus) in 19
stomachs; grapes in 12 stomachs, all in the month of October or later;
blackberries or raspberries (Rubus) identified in 4 stomachs; pepper
fruits in 2 stomachs; figs in 1 and mistletoe berries in 1. Besides
these 9 stomachs contained pulp or skins that could be identified only
as fruit. From this it appears that elderberries are the favorite fruit
of the bluebird. Fortunately these are nearly always to be had in
California. Most of the grapes eaten probably were waste fruit, as
many of them were consumed in December and other winter months.

FOOD OF YOUNG.

Among the stomachs examined were those of several nestlings about
a week old. They were of interest as showing how large a proportion
of animal food is given to the young. In one brood of six the only
vegetable food found was a single piece of plant stem, which was
probably given accidentally with other food, and should properly be
classed as rubbish. The real food consists of grasshoppers and
crickets 90 percent, beetles 3 percent, and the remainder made «up of
bugs, caterpillars, and spiders. In another brood of four, grass-
hoppers and crickets constituted 97.5 percent of the food, and 1
stomach contained: nothing else. The remains of 11 grasshoppers
were found in one of these stomachs, and 10 grasshoppers, a cricket,
and a beetle in another. The only vegetable matter found in these
4 stomachs was a single seed of Polygonum.

Besides the stomachs of the western bluebird discussed above, 14

100 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY.

stomachs of the Arctic bluebird (Sialia arctica) were obtained.
They were taken in fall and winter, and, while so small a number is
not sufficient for positive conclusions, 1t may be said that the charac-
ter of the food closely resembles that of the other species in the same
months. |

The two species eat about the same proportion of animal and vege-
table food; the animal part consists of the same orders of insects,
while the vegetable part is made up of the same varieties of fruit.
In short, it may be said that if there are important differences in the
food habits of the two birds the evidence at hand fails to establish
the fact.

SUMMARY.

It seems scarcely necessary to comment on the foregoing statements
with regard to the bluebird’s diet in its economic relations. That the
bird is an eminently useful species is so patent that it hardly needs to
be pointed out. Whatever harm fruit growers have suffered from
birds, none of it can be laid at the door of the bluebird.

List of insects identified in stomachs of bluebirds:

COLEOPTERA.
Coccinella t. californica. Blapstinus sulcatus.
Hippodamia convergens. Blapstinus pulverulentus.
Polycaon stoutii. Rhigopsis effracta.
Aphodius rugifrons. Balaninus sp.
Blapstinus dilatatus. Sitones sp.

HEMIPTERA.
Saissetia olew. Sinea diadema.
HYMENOPTERA.

Messor andrei (ant).

Insects also were identified as belonging to the following families:

COLEOPTERA.
Carabide. Ptinide.
Staphylinidee. Scarabeeide.
Coccinellide. Cerambycide.
Histeridee. Chrysomelidee.
Hlateride. Tenebrionidie.
Buprestidee. Rhynchophora (superfamily).

Lampyride.
HEMIPTERA.

Reduviidee. Corimelzenide.
Capside. Scutelleridee.
Lygeeide. Jassidee.
Pentatomide. Coccide.

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U. S. DEPARTMENT OF AGRICULTURE
LIBRARY

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Full text of "Birds of California in relation to the fruit industry"

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