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U.S. DEPARTMENT OF AGRICULTURE
BIOLOGICAL SURVEY—BULLETIN No. 25

BIRDS THAT EAT THE COTTON’ BOLL. WEBI

ma REPORT OF PROGRESS.

BY

ARTHUR H. HOWELI

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WASHINGTON
GOVERNMENT PRINTING OFFICE
1906

U.S. DEPARTMENT OF AGRICULTURE
BIOLOGICAL SURVEY—BULLETIN No. 25

BIRDS THAT EAT THE COTTON BOLL WEEVI

Pete Olid OH PROGRHSS

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1 1907

LETTER OF TRANSMITTAL.

U.S. DEPARTMENT OF AGRICULTURE,
BIOLOGICAL SURVEY,
Washington, D. C., May 3, 1906.
Str: I have the honor to transmit herewith for publication as Bul-
letin No. 25 of the Biological Survey a report of progress relating to
the birds that feed on the boll weevil, by Arthur H. Howell. As a
result of work in 1905 our knowledge of the part birds play in the
destruction of the pest has been considerably extended, and several
additions have been made to the list of species known to prey upon
the boll weevil. The protection of these by law is earnestly recom-
mended.
Respectfully, C. Hart Merriam,
Chief, Biological Survey.
Hon. James WILSON,
Secretary of Agriculture.

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CONTENTS:

Rau CHO Me ene Cente Ao See PN Se Lg tea ce ee ee onde eee eee
IaLocviess OlmUN@rINVeSuICAtONee sf ogee ga eis ss ee ee eee eee ee ce eeeeeeeceee
Comparison of summer and winter conditions...........-...-.-.---------------
SIMI AVRO TESU Se uemeunmm ye eee ke te ce ne pew eS evo ee dee kee
Status of the species of birds known to eat the boll weevil........-...-.---.-----
ResulissorobservatlonsinelQWorte: - 2 jeiti o.oo e se ee ee eet oe ee see ewes

Statisromthe bollkweoavilesee tees) 20 ka le ee Sees

Conditions of bird life in the summer of 1905. ......-.-.---.-----------1---
Summary OlObsenvaliONSMiNnlOU ow (2.1 s oc Le tse sees one eee emse oe
Schedulevof stomachvexamunations......-...-....---2---.t--5-.<- ee eae

BIRDS THAT EAT THE COTTON BOLL WEEVIL.

INTRODUCTION.

The problem of controlling the ravages of the cotton boll weevil in
the United States is of such moment that it is being studied by the
Department of Agriculture from a number of different standpoints.
One of these is the relation of birds to the weevil. Accurate informa-
tion as to the value of our native birds as destroyers of this pest is-of
considerable importance to the cotton grower, but such information
can be obtained only by means of careful and continued observation .
in the field, supplemented by study of the stomach contents of the
birds. Field observations alone, unverified by stomach examinations,
have proved unreliable. Birds may be observed picking insects from
cotton plants, but it does not follow that the insects are boll weevils;
nor is the statement that boll weevils have been found in birds’
stomachs, if made by persons unaccustomed to the identification of
insects, to be accepted as conclusive. Insect remains in a bird’s
stomach are nearly always in a more or less disintegrated condition,
so that identification of the species is difficult and requires the services
of a specialist.

Investigation of the problem was begun by the. Biological Sumeee
in the fall of 1904 under the direction of Vernon Bailey. The results
of this study, with a summary of work done by the Bureau of
Entomology, were published in a special bulletin by Mr. Bailey in
1905.¢ Stomachs of 38 species of birds were examined, and 11
species were found to have eaten boll weevils. The number of
species known to feed on the weevil was increased to 20.

PROGRESS OF THE INVESTIGATION.

During 1905 investigations were continued by the Biological Survey,
and particular attention was devoted to the seasons about which
least was known—namely, the period from February to October.? The

a Bulletin 22, Biological Survey.

b Field work was carried on by James H. Gaut in three localities in Texas for periods
aggregating nearly six weeks, as follows: At Hempstead, February 21 to March 3; at East
Bernard, May 2 to 17, and at Columbus, May 18 to June 1. A considerable number of birds’
stomachs were obtained by him, but as no traces of the boll weevil were found in any of
them they are not considered in the present bulletin.

8 BIRDS THAT EAT THE COTTON BOLL WEEVIL.

work was taken up by the writer early in July and continued until
October 20. Stomachs of 62 species of birds were collected and
examined, of which 12 species and 108 individuals were found to
have eaten boll weevils. Detailed results of the summer observa-
tions will be given later. 7

COMPARISON OF SUMMER AND WINTER CONDITIONS.

During the growing season of cotton the adult weevils are concealed
the greater part of the time on the buds, or ‘squares,’ where the enfold-
ing bracts afford almost complete protection from most of their
enemies; this fact largely explains why comparatively few weevils
are eaten by birds during the summer months. The amount of time
they spend on the wing and the distance they fly from place to place
are not well known, but it is only during the period of maximum
infestation that any considerable proportion of the insects can be
found in exposed situations. After the first hard frost, weevils begin
to leave the cotton plants and seek sheltered places in which to hiber-
nate. During this period their numbers are materially reduced, but
in favored seasons many weevils successfully pass the winter in their
retreats. Rubbish piles about the borders of fields apparently furnish
the most desirable hibernating quarters, and in such situations the
weevils are exposed more or less to the attacks of ground-feeding
birds. They are said to make use also of the hiding places afforded
by the cotton and corn stalks which have been left standing.

Investigations thus far made show that while fewer weevils are
destroyed by birds in winter than in summer, the number of species
of birds that feed upon them in winter is somewhat greater. The
birds which eat boll weevils in winter and spring and up to the time
of the breeding season of the insects are more important economically
than those which eat them in summer, for the reason that during the
season of nonactivity of the weevils a relatively long period must
elapse before they can make good the losses in their numbers, while
during the breeding season weevils multiply with astonishing rapidity.

SUMMARY OF RESULTS.

As a result of the investigation of the relations of birds to boll
weevils, details of which are given on succeeding pages, 28 species
have been ascertained to feed on the weevil, as follows:

Killdeer. Least flycatcher.
Quail. Cowbird.

Nighthawk. Red-winged blackbird.
Scissor-tailed flycatcher. Meadow lark.

Pheebe. Western meadow lark.

aExamination of the stomachs was conducted in the laboratory by Prof. F. E. L. Beal
and W. L. McAtee.

SUMMARY OF RESULTS. Q

Orchard oriole. Pyrrhuloxia.

Baltimore oriole. Painted bunting.
Bullock oriole. Dickcissel.

Brewer blackbird. White-rumped shrike.
Great-tailed grackle. American pipit.
Savanna sparrow. Mockingbird.

Lark sparrow. Brown thrasher.
White-throated sparrow. Carolina wren.
Cardinal. Black-crested titmouse.

Thirteen of the above species fed on the weevil during the summer
months, and 17 during the winter months, 2 species feeding upon the
insect both in summer and winter. About 18 percent of the stomachs
of these birds contained boll weevil remains, and the total number of
weevils eaten by them amounted to 40 percent of the number of birds
examined.

The orioles prove to be the greatest destroyers of weevils in summer,
and their near relatives, the blackbirds and meadow larks, in winter.
Orioles, because of their bright plumage, have until recently been
extensively used for millinery purposes, and thus their numbers have
been much reduced. Thousands were slaughtered, not alone in the
United States, but in Central America, where they pass the winter.
In view of their great value as weevil destroyers every effort should be
made to prevent their destruction for any purpose whatever. The
same suggestion applies with almost equal force to the nighthawk,
which is strictly insectivorous and is shown to be an enemy of the
boll weevil. During the migrations the nighthawk occurs in certain
sections of the South in great numbers and is frequently shot wantonly
or for food. The bird should everywhere and at all times be protected.

In the case of an insect so destructive as the boll weevil, which has
thus far defied all attempts at restraint and is steadily extending its
ravages into new territory, every natural check to its increase should
be encouraged. Though the extent of the services rendered by the
avian enemies of the insect may sometimes seem small or even insig-
nificant, in reality their cumulative effect is very important.

Birds are not the least important of the boll weevil’s natural ene-
mies, and every species ascertained to feed on it should be protected
at all times and places, not only in the cotton-producing area, but
along their migration routes. Of the birds known to eat the weevil the
following are at present not protected in Texas: Killdeer plover, cow-
bird, red-winged blackbird, Brewer blackbird, and great-tailed grackle,
or ‘jackdaw.’ Others, including some of the most valuable species,
though protected by statute, are often wantonly destroyed through
ignorance of the important work they perform.

There can be no question as to the usefulness of the killdeer, and
it should be included among the species protected at all seasons.
The economic position of the various species of blackbirds is not so
31019—No. 25—06——2

10 BIRDS THAT EAT THE COTTON BOLL WEEVIL.

clear. A study of their food made by Prof. F. E. L. Beal shows that
some species, notably the Brewer blackbird and the great-tailed
erackle, may at times be injurious to corn and other grain. However,
the season in which blackbirds render the greatest service in destroying
boll weevils, namely, winter and early spring, is not the season when
they are likely to damage growing crops. And, furthermore, a very
large proportion of the blackbirds leave Texas during the summer
months. It seems, therefore, that in protecting them in winter, when
they visit the cotton fields, the farmer is making no mistake.

In addition to protective bird laws the whole community should be
informed as to the value of insectivorous species, with a view to the
cultivation of popular sentiment in favor of their preservation. With-
out this sentiment, and the resulting codperation on the part of the
people, protective laws are of little value.

STATUS OF THE SPECIES OF BIRDS KNOWN TO EAT THE BOLL
WEEVIL.

In the summary which follows, the results obtained by previous
investigations are combined with those secured during the past season,
thus bringing together all that is at present known concerning the
relations of birds to boll weevils. The tables at the close furnish a
partial list of the birds which have been examined in the course of the
investigations, arranged according to the seasons, and show at a
glance the species that have eaten weevils, the number of individuals
of each species eating weevils, and the number of weevils eaten.

ORIOLES.

(Icterus.)

Observations carried on in 1905 indicate that in summer the birds
most useful in destroying boll weevils are the three species of orioles
occurring in the cotton belt of Texas—the orchard oriole, the Balti-
more oriole, and the Bullock oriole. Of these the orchard oriole,
although apparently less numerous than the Bullock oriole, is more
generally distributed over the cotton-growing area, and is also the one
which is the most successful weevil destroyer. Of the 84 specimens of
this bird examined, 26, or about 31 percent, had eaten boll weevils;
the total number of weevils taken by the 26 birds was 47, an average of
nearly 2 to a bird, or 56 percent of all the birds examined.

The Baltimore oriole occurs as a summer resident in Texas only in
the extreme northern and eastern portions, but during the migrations
it is common throughout the State as far west at least as Karnes
County. The 27 stomachs examined were taken between August 31
and September 22; six of them contained boll weevils, the total number
of weevils found being 10, which is 37 percent of the number of birds
examined.

BLACKBIRDS AND MEADOW LARKS. ll

The Bullock oriole is abundant in western Texas, but is not found
much to the eastward of the longitude of Corpus Christi. It is abun-
dant at Beeville and Runge, but is very rare at Cuero. Of the 144
specimens examined, 39, or about 27 percent, had eaten weevils; the
total number of weevils eaten was 131, which is an average of more
than 3 to a bird, or 91 percent of the number of birds examined.

All three species of orioles are migratory and spend only the spring
and summer months in Texas. They usually arrive from the south
between the 10th and 20th of April and depart late in September.
It is unfortunate for the cotton growers that these useful birds do not
remain in the State throughout the year, and it is likewise unfortunate
that over the greater part of the cotton belt only one species, and that
the smallest, is regularly found.

BLACKBIRDS AND MEADOW LARKS,

The blackbirds and meadow larks, which belong to the same family
as the orioles (/cteridx), seem to occupy a position complementary to
that of the orioles as boll weevil destroyers—that is to say, they con-
tinue during the winter the good work which the orioles do in the
summer. Nine species of this group occur abundantly in Texas in
winter, and six of these are known to eat the boll weevil.

The meadow larks are represented by several slightly different forms
or species, but since the food habits of all are practically identical they
may be considered together. Two hundred and fifty-seven specimens
have been examined, and of these, 40, or 15 percent, had eaten boll
weevils, the total number of weevils eaten being 50. Examination
of the records of the larks collected by Bailey in November and
December discloses an interesting fact, namely, that about as many
weevils were taken by them before the first hard frost as after the
frost. This shows that the larks are able to find the weevils while they
are feeding on the cotton plants as well as while they are hibernating,
and indicates that wherever the larks occur in summer in the cotton
belt they may be depended on to assist in the destruction of weevils.
The greater portion of central and southern Texas is, however,
deserted by the larks during the breeding season and until the middie
or latter part of October. None were seen by the writer at any of the
localities visited in the summer of 1905, except on the prairies between
Richmond and Columbus.

Four species of blackbirds are known to consume boll weevils, the
most important of which seems to be the Brewer blackbird (Luphagus
cyanocephalus). Ten stomachs of this bird were examined by assist-
ants of the Bureau of Entomology, and five of them contained a total of
11 boll weevils. This is the only species collected in winter in which
the number of weevils eaten averages more than one to a bird, and
if further investigations show this ratio to be the rule these blackbirds

12 BIRDS THAT EAT THE COTTON BOLL WEEVIL.

must be considered among the most useful of the winter visitants to
Texas.

The big ‘jackdaw,’ or great-tailed grackle (Megaquiscalus major
macrourus), was found to capture boll weevils in February, two of the
eight birds taken in that month having eaten one weevil each. Six
stomachs of the bird taken in summer contained no weevil remains.

The red-winged blackbird (Agelaius pheniceus) shows a smaller
percentage of weevils taken than most of the other species of this
family, but the enormous numbers of these birds which visit the cotton
fields during the migrations give to their work a place of some
importance. Sixty-three stomachs, nearly all taken in the fall and
winter, have been examined, and two of them contained boll weeviis.

The cowbird ( Molothrus ater) is the only blackbird known to eat
weevils both in summer and winter, but the number consumed in each
case is small. Forty stomachs of this bird collected in winter showed
only 1 weevil in the contents, and 54 stomachs taken in summer
showed three containing 1 weevil each.

SPARROWS, GROSBEAKS, ETC.
(Fringillide.)

The members of this family are among the most abundant and gen-
erally distributed of Texas birds. Five species have been collected
during the summer months and nine during the winter months. All
five species taken in summer were found to have eaten the boll weevil,
but in nearly every case the consumption of weevils was small. The
only species which seems to feed upon them regularly at this season is
the painted bunting, and considering the abundance of these birds
and the fact that they feed extensively in the cotton fields, they must
be considered an important factor in reducing the numbers of weevils.
Eighteen birds, or nearly 17 percent of the number examined, had
eaten boll weevils, but in only one instance was more than one weevil
taken by a single bird.

The other species of this family which feed upon the weevil in sum-
mer are the western lark sparrow, the dickcissel, the cardinal, and the -
pyrrhuloxia; in winter, the white-throated sparrow and the western
lark sparrow. The number of weevils eaten by all of these is insig-
nificant.

FLYCATCHERS.

(Tyrannidz.)

About ten species of flycatchers occur commonly in Texas, but only
six of them are summer residents. Since these birds habitually cap-
ture their prey on the wing, they would not be expected to destroy
large numbers of boll weevils, which, except during their annual

NIGHTHAWK AND QUAIL. 13

migration, fly but little. Two species have been found to capture the
weevils in summer and one species in winter.

The least flycatcher does not breed in the State, but is present in
small numbers during the migration in August and September, and
probably also in spring. In spite of its small size and aerial feeding
habits the number of weevils eaten by this bird amounts to over
100 per cent of the number of birds examined, or an average of more
than two weevils to each bird eating them.

The scissor-tailed flycatcher, although an abundant species, appar-
ently destroys very few boll weevils. Only 4 of the 64 birds examined
had eaten weevils, the total number of weevils eaten being 6.

The phebe is the only flycatcher which passes the winter months in
Texas. Thirteen stomachs taken in November and December have
been examined, three of which contained one boll weevil each. This
bird does not occur in Texas during summer.

NIGHTHAWK.
(Chordeiles wirginianus henry.)

The number of stomachs of this bird examined is too small to
definitely settle its status as a boll weevil destroyer, but the fact that
two of the four birds examined had eaten weevils, one having taken
six weevils at a meal, indicates that the species is probably, at least
at certain seasons, one of the most important enemies of the pest.
This evidence should serve as an effective argument in favor of the
preservation of the nighthawk.

These birds, commonly known as ‘bull bats,’ are often killed for
food, particularly in Louisiana, Florida, and other Southern States,
and they frequently serve also as targets for sportsmen who wish to
try their skill as wing shots. In view of their importance as insect
destroyers, nighthawks should at all times be rigidly protected.

QUAIL, OR BOBWHITE.
(Colinus virginianus texanus.)

Much has been written concerning the quail as a destroyer of boll
weevils, and many persons believe that it consumes them in large
numbers. Stomach examinations, however, fail to substantiate this
theory, for among 144 stomachs examined only one contained a boll
weevil. The bird that ate this one was killed at Seguin in November
by Vernon Bailey. There is still one season of the year during which
the quail has been imperfectly studied, namely, the period from
January to June, inclusive, and it is possible that investigation during
those months may result in a different showing for the bird. The
sround-feeding habits of quail make it practically certain that few if
any boll weevils are taken by them in summer.

14 BIRDS THAT EAT THE COTTON BOLL WEEVIL.

KILLDEER.
(Oxyechus vociferus.)

One killdeer taken in February was found to have eaten three boll
weevils. Further observations at the same season may not improb-
ably produce additional evidence of this bird’s value as a weevil
destroyer. The killdeer frequents plowed fields, often in large num-
bers, and the destruction of weevils at the period of spring plowing
is a highly important service. The present game law of Texas affords
no protection to this bird, a defect which should be remedied by
legislation. Meanwhile an enlightened public opinion should serve
to prevent its destruction for any purpose.

MOCKINGBIRD.
(Mimus polyglottos.)

In view of the abundance of the mockingbird in and about the
cotton fields, both in winter and summer, a study of its food habits
with relation to the boll weevil is especially important. Sufficient
data were obtained in the summer of 1905 to demonstrate that this
bird feeds only sparingly upon the weevils at that season. Of the
stomachs examined, only four, or about 5 per cent of the total number,
contained boll weevils. Specimens taken in winter are too few to
furnish conclusive evidence as to the mockingbird’s value at that
season. Only 11 winter specimens have been examined, and of these
2 contained 1 boll weevil each.

OTHER SPECIES.

There remain to be mentioned five species of birds, belonging to
as many different families, which have been found to eat the boll
weevil. They are the white-rumped shrike, the American pipit or
titlark, the brown thrasher, the Carolina wren, and the black-crested
titmouse. The most useful of these seem to be the titlark and the
Carolina wren. The importance of both has been emphasized by
Mr. Bailey in a previous bulletin, and no additional evidence has
since been obtained. The titlark (Anthus pensilvanicus) is an abun-
dant winter resident, and of the eight specimens collected three had
eaten boll weevils.

The Carolina wren (Thryothorus ludovicianus) is common in winter,
but rather rare in summer. Of the seven birds killed in winter five
had eaten boll weevils.

The white-rumped shrike, or ‘loggerhead’ (Lanius ludovicianus excu-
bitorides), was ascertained by assistants of the Bureau of Entomology
to feed on boll weevils, two birds taken in December having captured
one and four weevils, respectively. Examination of additional mate-

OBSERVATIONS IN 1905. LD

rial, including nine stomachs taken in summer, furnishes no additional
records of boll weevils eaten by this bird.

The two remaining species, the brown thrasher and the black-
crested titmouse, find a place in the list of boll weevil destroyers on
the strength of having eaten a single weevil each.

RESULTS OF OBSERVATIONS IN 1905.

STATUS OF THE BOLL WEEVIL.

The winter of 1904-5 was unusually severe in Texas, and the
spring was remarkable for excessive rainfall over a large part of the
cotton-growing area of the State. The months of July and August
were characterized by extremely hot, dry weather. To what extent
the winter climatic conditions reduced the numbers of weevils it is
difficult to state, but it is certain that during the spring and early
summer of 1905 weevils were much less numerous than they usually
are at that season. This is shown both by the comparatively slight
amount of damage done to the cotton crop during the early part of
the growing season and by the small number of adult weevils found
in July in many cotton fields known to have been seriously infested
at a corresponding date in 1904. The entire absence of boll weevil
remains from the stomachs of many species of birds known to eat
the boll weevil, taken in February, March, and May, also indicates
the extreme scarcity of the weevils at that season. Gaut examined
several thousand young cotton plants at Columbus in May and was
unable to find a single weevil. The writer visited the same locality
the last week in July and found the infestation even then very slight.
This was true of a number of other widely separated localities visited
during June and July.

it isa well-established fact that dry, hot weather during the summer
months is extremely effective in checking the increase of boll weevils,
and their scarcity during the summer of 1905 is partially explained
by the prevalence of such weather. While in some localities during
the late summer, weevils increased sufficiently to do a moderate
amount of damage, at other localities which had suffered greatly from
their ravages in 1904 the damage during 1905 was inconsiderable,
and even as late as September very few adult weevils could be
found at these localities.

The entire season, therefore, was not favorable for obtaining con-
clusive results with regard to the relations of birds and weevils.
Observations during a season in which weevils are more abundant
would doubtless show a larger number of species of birds feeding upon
them and a greater number of weevils consumed per bird.

16 BIRDS THAT EAT THE COTTON BOLL WEEVIL.

CONDITIONS OF BIRD LIFE IN THE SUMMER OF 1905.

Birds were abundant at only two localities visited in the summer of
1905. At three localities they were moderately numerous, while at
five localities they were very scarce. During the month of July,
which includes the last part of the breeding season of most species,
they were scarce at all localities visited. At Gurley, Texas, on July 20,
a count was made of all the birds seen to visit a large cotton field in
the river bottom, bordered on two sides with woods and thickets.
Forty individuals of 10 species were noted in about six hours in the
area under observation, which included about 100 acres. This result
is fairly typical of conditions prevailing in other localities visited
during the same month, except in regions where the presence of cot-
ton worms offered an especially attractive food supply.

The greater part of August and September was spent at two locali-
ties in the arid mesquite belt of Texas—Beeville and Runge—and
here birds, both resident species and migrants, proved to be abun-
dant. Between September 23 and October 20 a number of different
localities were visited, from Medina County on the west to Waller and
Grimes counties on the east, and at every place a marked scarcity of
bird life in and about the cotton fields was noted. Peculiarities in
the distribution of the food supply, not as yet well understood, proba-
bly account in a measure for this scarcity. The tendency of certain
species of birds after the breeding season to wander in search of food is
quite pronounced. This habit is well illustrated by observations on
the varying abundance of cuckoos, mentioned later.

SUMMARY OF OBSERVATIONS IN 1905.

Cuero, July 6—7.—At this time the cotton plants were in fine con-
dition, 3 to 4 feet high and full of blossoms and bolls. Weevils were
very scarce, some fields being moderately infested and others not at
all. No adult weevils could be found, and the average number of
larvee in fallen squares was about 12 to every 100 hills.

Birds were not abundant, and practically the only species seen feed-
ing among the cotton plants was the orchard oriole. Of this species
only one small flock was seen, and but one of those taken had eaten a
boll weevil.

Gurley, July 10-22.—Cotton was in about the same condition here
as at Cuero the previous week, perhaps a little less advanced.

Weevils were more abundant than at Cuero, though it was practi-
cally impossible to find adults. Forty hills in the worst infested fields
were carefully searched without finding a single individual. Exami-
nation of all the fallen squares under 20 hills produced 34 larve, 4
of which were dead.

Birds were fairly common, and the following species were seen in the
cotton fields: Quail, downy woodpecker, scissor-tailed flycatcher,

OBSERVATIONS IN 1905. 4 Lor

wood pewee, orchard oriole, lark sparrow, cardinal, painted bunting,
purple martin, and mockingbird. The orchard oriole and the painted
bunting were the most numerous and were the only ones seen feed-
ing among the cotton plants. Of the stomachs examined from this
locality only about 5 percent contained boll weevil remains. Four
of the 18 orchard orioles examined had eaten a total of 6 boll weevils,
and 2 of the 20 painted buntings examined had eaten 1 weevil
each.

Cameron, July 24-26.—Cotton was in the same flourishing condition
here as at Cuero and Gurley.

Weevils were by this time quite numerous. Twenty-five hills of
tall cotton in a bottom-land field were searched and 9 adult weevils
found, most of them crawling on the upper part of the stalks. Over
50 percent of the squares in this field were infested.

Birds were rather scarce, the only species which were at all numer-
ous in the cotton fields being the orchard oriole, lark sparrow, scissor-
tailed flycatcher, and quail. Of the 9 orchard orioles taken, 4 had
eaten a total of 7 weevils. One painted bunting and 1 least flycatcher
were taken, each of which had eaten a boll weevil.

Columbus, July 28-29.—Cotton was well advanced here, as at
localities previously visited, but many of the fields had been attacked
by the cotton leaf-worm, which proved to be very attractive food for
the birds. Weevils were very scarce, some fields being very slightly
infested, others containing from 5 to 10 percent of infested squares.
Birds also were rather scarce, the only species seen in any numbers
being the orchard oriole. Of 8 orioles examined, 2 were found to
have eaten 1 weevil each.

Beeville, August 3-22.—During this period cotton picking was in
full progress, and although in some fields the dry weather was
beginning to retard the formation of new buds, many blossoms were
opening every day.

Weevils were abundant and quite evenly distributed. On August
7 the fallen squares were collected from 20 hills of cotton, and in them
were found 74 weevil larve, 39 of which were dead, evidently as a
result of the hot weather. On August 20, 50 hills were examined for
adult weevils, and 43 individuals found. The cotton leaf-worm had
appeared only in very small numbers and in isolated spots.

Birds were abundant about the borders of the fields, in the mesquite
thickets, and along roadsides. Large numbers of certain species also
visited the cotton fields daily. Of the birds collected here, about 15
percent had taken the boll weevil, 41 individuals of 8 species having
eaten a total of 129 weevils. During the early part of the month
(August) the most abundant species of bird in the cotton fields was
the painted bunting (Cyanospiza ciris). From 100 to 200 of these
birds were seen in a single field nearly every morning. After about

18 BIRDS THAT EAT THE COTTON BOLL WEEVIL.

the middle of the month, however, their numbers became much
reduced, and by the 20th the average number seen in a day was not
over 15. To some extent they fed on the ground, but spent much
time climbing among the cotton stalks. They were partial also to weed
patches. Thirteen birds, or about 15 percent of those examined, had
eaten weevils, only one having taken more than a single weevil at a
meal.

Even more abundant than the painted bunting was the lark sparrow
(Chondestes grammacus strigatus), but unfortunately its ground-feed-
ing habits preclude the possibility of its destroying the boll weevil on
a large scale. Lark sparrows fairly swarmed along roadsides and in
the more open portions of cotton fields, but only one of those examined
contained a boll weevil.

The dickcissel (Spiza americana), another of the native sparrows,
having habits somewhat similar to those of the lark sparrow, was
found in the cotton fields in considerable numbers. Its record as a
weevil consumer was somewhat better than that of the lark sparrow,
for of the 19 birds examined 2 had eaten 1 weevil apiece.

One of the commonest birds at Beeville was the handsome pyrrhu-
loxia (Pyrrhuloxia sinuata terana), a large, thick-billed sparrow or
grosbeak, related to the cardinal. The favorite haunts of these birds
are the mesquite thickets, but they not infrequently visit the cotton
fields. Two of those collected had each eaten a boll weevil.

The birds which proved to be the most important enemies of the
boll weevil were the Bullock oriole (/cterus bullocki) and the orchard
oriole U/cterus spurvus), but unfortunately neither of these was very
abundant. The orchard oriole, as in other localities where observa-
tions were made, habitually fed among the cotton stalks. Seven-
teen individuals were collected, and of these, 8 had eaten a total
of 23 weevils. The largest number taken by a single bird was 7, and
another had taken 6. The Bullock orioles, though more numerous
than their smaller cousins, were seen less frequently in the cotton,
their favorite haunts being the mesquite thickets. Twenty-seven
individuals were collected in and near the cotton fields, and of these
27 birds 12 had eaten a total of 80 weevils. The greatest number
eaten by a single bird was 41, and 2 others had eaten 11 and 9,
respectively. These three birds, all of which were adults, were taken,
together with five young birds, about 9 a.m. on August 16, while
feeding in a cotton field. Of the five young, one had eaten two
weevils and another three. These records would seem to show that
the orioles know perfectly well where the weevils hide and seek them
as a chosen article of food. At this season practically all the weevils
are concealed beneath the enfolding bracts of the buds, or ‘squares,’
and it is improbable that a bird could capture as many as 41 during
a single morning without opening the bracts in search of them. It

OBSERVATIONS IN 1905. 19

is significant also that the adult orioles, naturally having a better
idea of where to hunt for weevils, consumed a much larger number
of them than the young ones.

In addition to the four species of sparrows and two species of orioles
found feeding on the weevils, there were also two species of flycatchers
which captured them in small numbers. The scissor-tailed flycatcher
( Muscwora forficata), though quite numerous in the pastures and along
roadsides, visited the cotton plants very infrequently. Eleven indi-
viduals were collected, one of which had taken two boll weevils, and
this one, strangely enough, was taken in a mesquite pasture at some
distance from the cotton fields. The least flycatcher (Empidonax
minimus), which was present in small numbers as a migrant, was
occasionally seen to visit the cotton stalks, and of the three individuals
collected two had taken boll weevils, one having eaten four, the other,
one. .

In addition to the birds already mentioned, the following species were
more or less numerous in the cotton fields: Mockingbird, quail, yel-
low warbler, great-tailed grackle, cardinal, and curve-billed thrasher.

Runge, August 23-September 5; September 11—23.—During the first
half of this period the growth of cotton had practically ceased, as
the result of protracted drought. During the latter half, after a
few light showers, the cotton plants began to put forth new buds and
leaves. The cotton leaf-worms were very abundant at this locality;
nearly all the fields had been attacked by them, and over large areas
the plants had been entirely denuded of leaves and buds.

Weevils were quite abundant, but by reason of the ravages of cotton
worms they had been forced to concentrate on the small patches of
cotton containing leaves and buds. In such places they averaged
about 2 weevils to a hill, the greatest number found in one spot
being 19 on 5 hills. In the fields where cotton worms were still at
work the weevils averaged about one to every two hills.

Birds were abundant in and about the cotton fields, and in the mes-
quite thickets. Cotton worms furnished a much more attractive and
easily obtained food supply for the birds than weevils, as was shown
both by field observations and by stomach examinations. Birds
were much more numerous in fields infested with the cotton worms
than in those which were uninfested, and in the case of certain species
their presence or absence in a given locality was largely determined
by the abundance of these insects. This was notably true of the
yellow-billed cuckoos, which on August 23 were found in large num-
bers about an isolated field where cotton worms were abundant; but
on September 2, after this brood had all pupated, not a single cuckoo
could be found there, although they were still numerous in fields a few
miles away.

Cotton worms were contained in the stomachs of nearly every
species of bird collected at Runge, and they formed a large percentage

20 BIRDS THAT EAT THE COTTON BOLL WEEVIL.

of the food of many species, notably the cuckoos, orioles, and mock-
inebirds, which were the commonest birds in the fields. The con-
sumption of weevils by the birds therefore was probably less than
it would have been had there been no cotton worms.
Nine species of birds were found feeding on weevils in this locality,
52 individuals, or more than 12 percent of those examined, having
eaten a total of 88 weevils. As in other localities visited, orioles were
the greatest consumers of weevils, although the proportion of weevils
to birds killed was larger in the records of the nighthawk and of the
| least flycatcher.
| The nighthawk (Chordeiles virginianus henry) was quite numerous,
but unfortunately it was not suspected of eating weevils, so that only
| four specimens were taken. Of these, 2 had eaten weevils; one col-
lected on August 25 had eaten 6, and one on September 15, one wee-
| vil. The first of these was shot while flying over a cotton field, the
| other while resting on a tree, both at about 10 a.m. In the first
. instance 2 of the 6 weevils were almost entire, showing that they had
| been captured only a short time before. Since these birds invariably
feed on the wing, the weevils must have been flying at the time they
| were captured.
| The least flycatcher was present in small numbers, and 4 individuals
were taken, 2 of which had eaten weevils—one eating 4, the other, one.
| The scissor-tailed flycatcher, a much more abundant species, cap-
| tured only a small number of weevils. Of the 30 individuals collected,
| 2 had eaten a total of 3 weevils.

Three species of orioles were present at this locality—the orchard
oriole, the Baltimore oriole, and the Bullock oriole, the last being the
| most abundant and also the greatest destroyer of weevils. Of 30
orchard orioles examined, 7 had eaten a total of 8 weevils. In this
portion of Texas the Baltimore oriole is a migrant only. The first
arrivals from the North were seen on September 13, and during the
| next ten days they werecommon. Five of those examined had eaten a
| total of 9 weevils. The Bullock oriole is a common breeder here, and

they were still numerous at the time of the writer’s departure.
Although partial to mesquite trees, they were occasionally seen in cot-
ton fields, and the stomach examinations show that about one-fourth
of those killed had eaten weevils. In all, 27 stomachs of this bird were
found to contain a total of 51 weevils, the largest number eaten by a
single bird being 5. The small percentage of weevils taken, in com-
parison with the number taken by the same species at Beeville, is
explained by the greater abundance of cotton worms at Runge.
Practically all the orioles of the three species taken at the latter place
had eaten either the caterpillars or the chrysalids of the cotton worm,
and these insects formed more than 80 percent of their food.

Both the cardinal and the painted bunting were found to be eating
the weevils, but neither species was abundant. Four cardinals were

SCHEDULE OF STOMACH . EXAMINATIONS. 2]
examined, 2 of which had eaten a weevil. Fourteen painted bunt-
ings were taken, 2 of which had likewise eaten 1 weevil apiece.

Mockingbirds were very common, and many were seen in the fields
feeding on cotton worms. Twenty-nine specimens were collected, 3
of which had taken 1 weevil apiece.

Other localities —During September and October five additional
localities were visited, as follows: Castroville, September 25; Secuin,
September 26-29; Matthews, Colorado County, September 30—Octo-
ber 4; Hempstead, October 6-9, and Navasota, October 10-16.
Cuero was also revisited September 6-9 and Gurley, October 17-20.
At these localities, with the single exception of Cuero, weevils were
found in considerable numbers, but at most places birds were
remarkably scarce, and the stomachs of those collected contained no
weevil remains. At Matthews, in the Colorado River bottoms, red-
winged blackbirds and bronzed grackles were abundant, though com-

paratively few of them fed in the cotton fields.

SCHEDULE OF STOMACH EXAMINATIONS.

In the following lists are enumerated all the species thus far exam-
ined in connection with boll-weevil investigations. ¢

Record of birds examined which had eaten boll weevils.

During Jan.,|During Apr.,| During July, | During Oct.,
Feb., and May, and Aug., and Nov.,and
Mar. June. Sept. Dec.
; ea Ney eel e=rbeyl |e Peer reece eae esc pce almAla., ala &
Species. EVSSlSSERISSSSIER feISS ES [Felss
Bae So essere sts Bo\" oO ag lkal- oS
SEES CaS ee SPS) sg [Fe S3\oE Peles
SRISSIS S16 RISES S| Sz ISS] SE] SR ICSISS
AA SIA ei4 ose 7 © AS\2 2 Zo Ase
Kalldeer (Oryechus voctferus).2. = 2.s2-s 20-522 Delia he lier || eal tee eve Ay |e _,|Maeee 5 1p es as |e
Texan quail ( Colinus virginianus teranus) .... .\..--)..--)---- ler eee See 367 Fi s<<| aes 108 | 1 1
Western nighthawk ( Chordeiles v. henryi) .....|....|...-|.--- reel Pe Aaln 32 7 fal eel peered Se a
Scissor-tailed flycatcher ( Muscivora forficata)..|....|....|...-.|----|---- [eee lO? 4 Ga eee ee
PINGS NS (QMO DUS OMAN) 3 os niga cabo onsaseonese| Sosalsosaleeseleees pees | || LN, Rete beet pelt a Ta a3 3
Least flycatcher (Empidonax minimus) .....-.-|-- i lee eet | Seren (ete el Oi Dili Ila see | ee
Cowbinds CMolothrus ater) oes nse ee 16 jf He cai WS le Bilt Daal -sNeieeem
Red-winged blackbird (A gelaius pheniceus)...| 3 |...-|...-|---- [eee be StL | era Bese | 49 | 2 2
Meadow lark (Sturnella magna and subspecies) | 3 |..--|.---|---- Sm [eon Ue gee a a 183 | 28 | 32
Western meadow lark (Sturnella neglecta) ....- at [Bees eee | 2 ee (Seer (ieran | eee | seer 66 | 12); 18
Orchard oriole (Icterus spurius) ........0..---.|..-- {i ceebe | aie [Lt [ene jpn S47 26nl) 47a eee ee eee
BAtIMOLe OLMOlelClCleTUS GALIDUIG) == a2 2 aa eee | aac o\hecciesec|-e-clhces|ac.- 27 | 6 LO Se s|2- clare
Bullock oriole (Icterus bullocki) .............--- Hegde, on ck Mee crn ce TAA e398 1318 |e ses | See ee
Brewer blackbird (Euphagus cyanocephalus)..| 5| 3| 9 |...-|....|..--|.....|----|.---- 5] 2 2
Great-tailed grackle ( Megaquiscalus major ma- |
CEOUTAUS Meee st ree ee ee Sho KE oli sers Nee = Gree alse Di | Boat aeaee
Western savanna sparrow (Passerculus s.alau- | |
LENS) er ea oe eet ate vices |oerne |e ee 2 | eRe Swe cho! see c,arei cee clemee laoe.s& Toler 3 | mea L
Western lark sparrow (Chondestes grammacus | | | |
SUPA) 5 ASAE SAE ES 5a) AN ae ey Se pi oe Pee aan ae i| | Gr el ts BG aes ee |. one
White-throated sparrow (Zonotrichia albicollis) |....|....|....|----|--.-|----|.---- ees eine oe 1
Cardinal ( Cardinalis cardinalis).......-..----- [Pereeee /tarare'lts Masel ote. 2.0 esses ese | feller (e708
Texan pyrrhuloxia (Pyrrhuloxia sinuata terana)|....|.---|----|----|---- Ream RPO |) le 228 | een | eee
AINLedeounbineaCCYANOSDIZG-CITtS) acs sseciigc c2)ees-|ee ee leec-|a2cc|ass-|5--- 107: 218% (iye1 9! | = 28 ee eee
Dickcissel)(Spiza americana) ..-...-...----.---- S8e oe soe.) nee Hae eae ys a oe Pe a Pe I
White-rumped shrike (Lanius l. excubitorides).| 1 |.-.-.-|...-|----|----|---- 9) ean) ese 125/02 5
American pipit (Anthus pensilvanicus) ........|-- Bale: ee 1 bes hoa en Pe eRe eseae 8| 3 4
Mockingbird (Mimus polyglottos) .........--.-- 6 yor leroaiecale (3 ed We cello cee
Brown thrasher ( Tozostoma rufum) .........--|--..|/--- | Sera eemene eee eiey (Sl be ee ee 4 Gee 29) 1 1
Carolina wren ( Thryothorus ludovicianus) .....|----|---- [Saeesiecee (ere [eet aera stad orate eee 7) co 6
Black-crested titmouse (Bzolophus atricrista- |
CLES) ere tee ees ee 2S Tne [SSS Baccleose Baad eee peas eg | eee eee 74) onl 1

a Including those examined by Bureau of Entomology.

22 BIRDS THAT EAT THE COTTON BOLL WEEVIL.

Record of birds examined which had not eaten boll weevils. 4

| Number of birds exam-
| ined during—
|
1 ~ Ties
Species. ee se ooo ae
) sa |e | 48 [88
Mont Sh | S |v2,.6
Se) a7 | .8 eee
As | a 2 lSPO
(RA |< > ‘|
MOUINING GOVE (ZCNAIGUTG, MACTOUTG) = Hao te ceieni- la, 2 oe tenis re sie ie oie wee oe So | yal Penne oe 115 112
Mexican ground dove (Columbigallina p. pallescens) ........------------------|------|--+---|--+--- 5
MellOw=piuled:CucKOOACCOCCYZUS AILETACONUS) 2. oon os cejpo cb oe ie nee oe cece ie eee teeeee 455)||- oe nie
Mexan woodpecker (Dryobates scalaris Oa0i7d1) 2.0... 32- ccc no ee oe sean nse lowe ce locate 4 2
Red-headed woodpecker ( Melanerpes erythrocephalus) ...........-.----------|------|------|------ 3
Red-bellied woodpecker (Centurus carolinus) .... 2. .2..2-- 2-002 e ee een nena e eee e|--e ee cere | 2
Golden-fronted woodpecker ( Centurus aurifrons) ...........---.--------------|+---+-|------ 4 | pee
re KeTRMOOLUDLESOUTOLUS)/. ~ mc eet eek ae one ee ce See ne eee eee pele erties [ares = «| 3
KRONE DITGsCLYTONNUS CYTARNUS) f= ooo cist eco Soa feeb ewloc -oees te wdees Reese te leekees|=ceeery Siisas ee
Wioodupewee, (CONLODUS VITENS ss see nelsaers 245-2 ee a ee ob eee vice ee claa eee [eee 4's | eee
Yellow-bellied flycatcher (Empidonazx flaviventris) .....-.....----------------|------|------ I ie
Seem va (CUGIMOCLILG ChISIOIO) aaa: sccite eeicon cance see sce aoe eons seioa ape ener | ences eee | 2
Rustysplackpird (Luphragus CavOlenwus) cmc c foiecs code ncse sade sce to eoee tee ele once feesee es [eee j 10
sronzed grackle (Quiscalus quiscula #neus) ....-...----- 222-22 -2e nee eee e fee eee Beasee 3) 3
Western vesper sparrow (Poccetes gramineus confinis) ..........-.-----.-----|------|------ | ee 11
Western grasshopper sparrow (Coturniculus s. bimaculatus) .......----------|------ | 2c oi2, 21 eee 5
White-crowned sparrow (Zonotrichia leucophrys) ......----------------+------ Vo werent eeean ||: aoraeye 4
Western tree sparrow (Spizella monticola ochraced)........-.---------------- Paeee oem eee iK
MEO <aS DATO Ws CR ASSCTCLIOMILACH) OP ae one ee ee ee ee oe ee eee ecee ee | eee ees) 9
MowheesGbzDil0 eTylhTOPRIRQUNUS) 22 sc cack coche eek we cee oes Steen bo we ee oa) oe oe | ae ee 6
IBINee LOS Dea (Guz GA COCLTULEO) A seen sed. so Sone = Nao sehen coe ae ik Bao ae {oe 3"| Stee
pin OMe UbITU CEO GILESILOTS) eee oe co ae ae Se Aniclc ae ose cece en eee wees { 2oks hn eee | UN Ne
Nashville warbler (Helminthophila rubricapilla) .............----------------- peer sal feed 32 AEG hae
PicllOwawalLDleniCD CNGTOCE, 2SIWU0) noe ee ee eon oes ce ee oe eon ace wice eee | ce ee |< 907 aes
Mournine warbler. (Geothiyprs philadéelphig)=«.. <2 =<... ene ee se eo 3 = |e ee |e | Sul eee
Curve-billed thrasher ( 7'oxostoma curvirostre) .........-.-..------------------ eet lee | 63a
Texan Bewick wren ( Thryomanes bewickii cryptus)-...........---------------- 1 oO ee | 3-| 2
Blneeeray onaccatcher (Poloplila, Ceriuled) 22. ow eee wee wn nen ae |e 2 eee |) 102
SIME DINGEC(SZOLIGISTOLIS) = sowie Seeman te se cee oe Dee ae nets ees ce eee ee aes eed ae 6

a A few species of which only one or two specimens have been examined are omitted from the list.

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