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Washington. D. C. v July 20, 1923

REPORT ON BIRD CENSUSES IN THE UNITED STATES
1916 TO 1920

By

MAY THACHER COOKE, Assistant in Biclogical Investigations
Bureau of Biological Survey

CONTENTS

Some notable bird- census results
Relative abundance of certain species
Essentials of a satisfactory census Density of bird population
More reports needed on certain areas Bird life of marshland
Results of bird censuses north o. Maryland and east of
the Plains Scarcity of birds in 1918
Results of censuses from southeastern States ss Yo Birds respond to pzolection
Results of censuszs from western Stales . . 2... 1

WASHINGTON
GOVERNMENT PRINTING OFFITE
1923

Washington, D. C. July 20, 1923

REPORT ON BIRD CENSUSES IN THE UNITED STATES, 1916 TO 1920.

By May TuacHER Cooke, Assistant in Biological Investigations,
Bureau of Biological Survey.

CONTENTS.
Page. Page
Pepa a: © oe ee ee eee ee ene 1 ; Some notable bird-census results...........-... 15
Methods of taking bird cemsuses........... 3 | Relative abundance of certain species.......... 21
Essentials of a satisfactory census.......... 4 | Density of bird population.................... 23
More reports needed on certain areas......-. Gf |. Biel life.of marshlands... o555.4s< 5-20: a4 ieee 24
Results of bird censuses north of Maryland and Birdie of the woodiande.<: 2~ 257 33.1 oe 27
IR GQ) 32) 00 i ee 6 | Scarcity of birdsim 1918:.<_- ....:-._...-_ 28 28
Results of censuses from southeastern States... 9 | Birds respond to protection.................... 31
Results of censuses from western States ....... 1D); JP SEMAITAB Ys A otk wees oot aot a ee te Wn Pe 33
INTRODUCTION.

Definite information regarding the number, distribution, and
relative abundance of the breeding birds of the United States is
greatly desired. The Biological Survey started an inquiry for this
purpose in the spring of 1914 and sent out circulars to many interested
persons throughout the country requesting their assistance. In
addition to the importance of the information desired, because of the
value of birds to agriculture, exact knowledge regarding the
abundance and distribution of birds was needed in formulating
regulations for the protection of game and other migratory birds,
the Congress having recently passed laws placing them in charge of
the Department of Agriculture. It was also important to ascer-
tain what effect the laws then in force had already had on the bird
life of the country.

The preliminary survey in 1914 proved so satisfactory that the
work was repeated the next year on a somewhat larger scale. The
results of the work in 1914! and 1915? revealed something of the
possibilities of this method of study—that it was a practicable means
of obtaining much important and valuable information, and that
thereafter it should be a permanent part of the work of the Bio-
logical Survey. As there are no funds available for this kind of
work, it depends entirely on the cooperation of volunteer observers.

1 Bull. 187, U. S. Dept. Agr., Preliminary census of the birds of the United States. 1915. ;
. ear a S. Dept. Agr., Second annual report of bird counts in the United States, with discussion
of results. 5

44125—23—Bull. 1165——1

2 BULLETIN 1165, U. S. DEPARTMENT OF AGRICULTURE.

The work has been continued, but unfortunately on a smaller
rather than a larger scale. During the war many persons were
unable to make the necessary surveys and some lost interest be-
cause of the impossibility of publishing the results obtained. The
returns for 1919 were so fewas to be of value for purposes of comparison
only, in those cases where the areas dealt with were previously, or
subsequently, reported upon. A gratifying increase in interest and
in the number of returns was shown in 1920.

For these seven years the bird censuses taken in the part of the
country north of Maryland and east of Kansas have been sufficient
in number to allow some generalizations as to the average bird
aaa but many more are needed from the Southern and

estern States before it will be possible to draw any conclusions as
to the bird life of these sections.

The counts of 1914 and 1915 showed slightly over one pair of birds
to the acre on the farm land of the northeastern section above men-
tioned, or approximately 800 pairs to the square mile. For the five
years 1916 to 1920, inclusive, there are fewer reports than for the
two earlier years, but the averages obtained agree fairly well with
those previously published, so that it seems probable that the figures
above stated are reliable. As yet nothing can be said about the num-
bers of the individual species, and only tentative statements are
possible regarding the relative abundance of a few of the most common
species.

EMaay problems concerning bird life can be solved by no other
means than by bird censuses; that some can be solved, in part at
least, by this work has already been proved, but many have not yet
even been touched upon. How many birds per acre breed in the
different parts of the country, in the permanent marshes, and in
the forested regions of New England, the eastern mountains, and
the Rockies? What is the relative abundance of the different species
in the country as a whole and in the different life zones, and how are
they distributed? Where are the centers of abundance for birds
generally and for the several species? Are birds most abundant
where they are most needed, about the farms, gardens, and orchards ?
How do altitude and latitude affect the numerical distribution of
birds? What effect on bird life has the presence of water, as a small
stream or a river, a pond or a lake? at fluctuations take place
in bird life from year to year, or over longer periods? When pro-
tection and encouragement bring about an increase in the number
of birds nesting on a given tract, are there actually more birds in
the locality, or is this increase due to a concentration of the
birds from a larger area for nesting purposes? How do birds
respond to changes in such environmental conditions as more intensive
cultivation, changes in crops, or the clearing of woodland? How
is irrigation affecting the bird life of the arid lands of the West?
What changes will occur there in numbers and species, and how
rapidly will they take place? How much have birds increased under
rotection? Are the present Federal and State laws adequate?
at changes, if any, are taking place in the numbers and relative
abundance of the several species ?

That the counts might be made in a uniform way and thus pro-
vide data which could be used in comparisons and in deducing the
desired information, each observer was given instructions regarding

4

REPORT ON BIRD CENSUSES, 1916—1920. 3

the selection of the area to be covered, the time at which to make the
count, and the information to be included in the report. As a
knowledge of methods followed is essential to an understanding of how
the conclusions here presented were reached, it will be well to outline
what are considered the best conditions and procedure in taking a
bird census. In the following discussion the experience gained from
the actual work is embodied with the early plans and instructions.

METHODS OF TAKING BIRD CENSUSES.

It is obviously impossible to enumerate all the birds in the country
or even in a small section, but the birds nesting on a tract of not
over 80 acres can be counted by one observer with considerable
exactness. The combined results of many such counts will furnish
a key to conditions in the country as a whole. The sample tracts
should represent as nearly as possible the average conditions for
their respective localities in regard to the proportions of woods,
orchards, crops, pasture, etc. It is, of course, impossible to find one
tract that contains all of these elements in exactly the right pro-

ortions, but the greater the number of tracts surveyed, the less will
be the chance of error in the resulting averages.

The plots of farm land chosen for the censuses should contain on
the average from 40 to 80 acres. A tract of less than 40 acres seldom
shows sufficient diversification to be representative; and an 80-acre
tract is as large as one person can accurately cover under most cir-
cumstances. When the enumerator lives on or near the land sur-
veyed and has the time to devote to the work, larger areas can be
and have been very satisfactorily worked.

Sometimes because of local conditions it is desirable to have a
census over alarge area. In such cases, especially if the tract shows
considerable diversity, the work is facilitated and the interest and
value increased by dividing it into two or more sections and treating
each as a separate count, thus indicating how the birds are distributed.
Contiguity of the tracts surveyed adds materially to the interest and
value of each, since not only is a larger area thereby represented,
but something of local distribution is shown. Two series of counts
from Kansas, elsewhere quoted somewhat at length, are excellent
examaples of this (pp. 11-12).

It has been deemed important that, so far as possible, areas be
selected on which conditions are not likely to change for several
years. Under such circumstances it will then be evident that
fluctuations in the bird life on these areas are not due to artificially
changed environment. Nevertheless, counts of all kinds are welcomed,
for it is impossible to have too many; moreover, the response of birds
to changes in environment is an interesting study in itself.

It is very important that counts be made on the same areas year
after year, in order that the records may give some basis for com-

. parisons. Only by the accumulation of large series of records

dealing with the same land can definite conclusions be drawn as
to average conditions or as to changes taking place—whether birds
generally or individual species are increasing or decreasing. A
study of the conditions that existed in the eastern United States in
1918 (see pp. 28-31) has shown the value of such series of records as
a means of studying fiuctuations in bird life.

4 BULLETIN 1165, U. S. DEPARTMENT OF AGRICULTURE.

The Biological Survey has advocated counting the singing males
as the most convenient way of taking a bird census, and this method
has given excellent results. The observer starts at daylight some
morning at the height of the breeding season and zigzags back and
forth across the selected tract, counting the singing birds. At that
season, when the migration is over and the birds are settled on their
breeding grounds, each male bird may be safely considered to rep-
resent a nesting pair, and early in the morning, before the insects
are flying and the birds begin feeding, the male is usually to be found
in the vicinity of thenest. |The count should be repeated once or
twice at intervals of a few days to be sure that no birds have been
missed and that all the birds counted are actually nesting on the area.

If the enumerator lives close by, one day’s count may be checked
by subsequent observations throughout the breeding season. When-
ever possible, it is well to go over the land again late in the season to
catch any late nesting species, such as coldfinches and waxwings.
To locate every nest is not necessary; unless the enumerator lives on
or very near the tract it is practically impossible to do so, and the
time required in any case is enormous. I[!xperience has shown that
a count of 50 acres can be made in three hours by the method outlined
and that subsequent observations throughout the summer make
almost no change. However, in the case of unusual species and
especially those outside their known breeding range, it is insisted
upon that the nest be located or other satisfactory evidence found as
proof that the birds were actually breeding in the locality and were
not merely wanderers or delayed migrants.

ESSENTIALS OF A SATISFACTORY BIRD CENSUS.

The observer must be thoroughly familiar with the birds breeding
in his locality, both by sight and song, in order that all the birds
found nesting on the selected area may be positively identified, or a
recognizable description given of such as can not be readily named.
Otherwise some snecies may be omitted and the report be not usable
since it does not tell the whole truth.

For a number of years the Biological Survey has been receiving
each year from several hundred volunteer observers throughout the
country reports on the arrival and departure of birds during the
spring and fall migrations. Some of these observers are well ac-

uainted with the birds, while others know only a few; in the case of
the latter, however, if their knowledge is accurate regarding the few
they do know, and if they are well situated to watch the birds and
note their first arrival, the fact that they do not know all the species
in no way detracts from the value of their records for the arrivals
and departures of the species noted. In making a bird count, how-
ever, such partial knowledge is worse than useless, and some reports,
doubtless entirely correct for the species listed, have had to be rejected
because the absence of the smaller and less conspicuous species
showed the reports to be incomplete. A census of breeding birds to be
of any value must tell the whole truth; it 1s not sufficient that rt shall tell
the truth as far as it goes.

Care must be exercised that the same individual be not counted

more than once, as there is danger of doing in the case of species in

which the two sexes are nearly or quite alike. This is one reason
in favor of counting only singing birds, in so far as is compatible

REPORT ON BIRD CENSUSES, 1916-1920. 5

with accuracy, though there will always be a few birds that fail to
sing at the expected time. }

A bird census should not be made until after the migration is
over and the birds are settled on their nesting grounds. Occasionally
belated migrants linger into the breeding season, but thorough famili-
arity with the local avifauna should make the elimination of these a
simple matter. If, however, some unusual species found is near the
edge of its known breeding range, its presence in the nesting season
should be carefully investigated and the nest located if possible, to
ascertain whether it is breeding there. Reports have sometimes been
found useless because the counts were made so early in the season
and certain species were so abundant that it seemed very probable
that some of the individuals listed were not yet nesting but were
migrants lingering in the southern part of their breeding ranges.
Birds seldom nest in large numbers on the edge of their breeding
range. On the other hand, if the count is made too late, the young
of the species that nest early may be on the wing and may have left
the area where they were raised.

A previous familiarity with the area surveyed is a help, and when
it is necessary to make the count on land with which the enumerator
is not well acquainted, it is a good plan to go over it several times
before the actual census is taken, that the work may be done thor-
oughly and accurately.

In selecting an area on which to take a census, it is better not to
choose a place where the birds are excessively abundant unless more
than one count can be made. Such places are very interesting as
showing how closely birds may breed, and data concerning them are
useful in learning the total number of birds in the country, but they
are not representative. If such a tract is chosen, the surrounding
territory over which these birds feed should also be considered,
prosarebly as aseparate count. Such areas furnish excellent material
or studies of local distribution and may yield interesting and valu-
able returns when an observer lives near enough and has the time
necessary to make several counts of the area of concentration and
of as much as possible of the surrounding territory. If these several
counts are repeated year. after year, the results will form valuable
series of records.

Some persons seem to have the impression that a bird census is
of no value unless it records a large number of birds per acre, and
have considered it not worth while to make a count unless such a
tract could be found. The actual truth concerning conditions is
what is wanted, and knowledge of the distribution of bird life on any
land contributes to this end. A count made on land that has few
birds is just as important, therefore, as one made in a bird paradise,
though probably not so interesting to the enumerator.

The final report should include an accurate description of the tract
surveyed, indicating its nature, whether moist bottomland or dry
upland; level, or broken and hilly; the number of acres in woods,
orchard, and garden, in lawns about buildings, in each of the farm
crops, and in pasture or meadow; and if there is waste land, whether
it is marshy, upland, brushy, or the like. The value and usefulness
of a report is increased if it contains information regarding the land
surrounding the tract surveyed, whether it is wooded, cultivated,
waste, or pasture; and if cultivated, whether in grain, hay, or garden

6 BULLETIN 1165, U. S. DEPARTMENT OF AGRICULTURE.

truck. Such supplementary information sometimes explains the
presence of unusual numbers or species of birds on the tract surveyed.

MORE REPORTS NEEDED ON CERTAIN AREAS.

The most important phase of bird life concerns its relation to man
and especially as it helps the farmer in destroying the enemies of his
crops. It is more important therefore to ascertain how many birds
inhabit the trees and shrubbery on the part of the farm actually
devoted to crops and in the fields immediately contiguous to it then
on land not devoted to agriculture; this should be borne in mind in
all investigations along this line.

Another matter worthy of careful attention concerns the number
of birds inhabiting certain areas which, while not devoted to agricul-
ture, are important because of their nearness to centers of human
occupation. Among such places are city parks, cemeteries, etc.,
where the presence of a large population of native birds is most
desirable. That birds are quick to recognize the advantages of
these sanctuaries, as they may be termed, where they find pro-
tection with food and shelter in plenty, is evidenced by reports that
have been received of censuses made on areas that included such land.

In 1916 two tracts of 40 acres each in Golden Gate Park, San
Francisco, averaged nearly 9 pairs of birds to the acre. At Omaha
12 acres of city park in 1916 had 33 pairs of native birds, representing
21 species, and 2 pairs of English sparrows; and in 1917 15 acres
sheltered 70 pairs of 20 species, all native birds. ‘Two years’ counts
made in the 44 acres of Woollen’s Gardens, at Indianapolis, showed an
average bird population of 320 pairs to 100 acres. In 1920, 80 acres
of the campus of Wellesley College had 111 pairs of 34 species of
native birds and 4 pairs of English sparrows. Five years’ counts
made on 95 acres in Highland Park, at Rochester, N. Y., show an
average of 205 nesting pairs, with a maximum of 214 pairs in 1917.

RESULTS OF BIRD CENSUSES NORTH OF MARYLAND AND EAST OF THE
PLAINS.

For the part of the country north of Maryland and the Ohio River
and east of the Great Plains enough counts have been made (see
Fig. 1) to make possible some deductions regarding the average bird
population of the farm land. This territory was studied in con-
siderable detail in 1915; but for the five years under discussion the
material at hand is not sufficient to make practicable quite so de-
tailed a study. The land surveyed has been classified, therefore,
simply as fields, woodland, orchard, and plowed land. The last
term, designating land in crops other than hay, is especially impor-
tant in a study of the distribution of bird life, for very few birds
nest on it; yet this is one of the types of land on which they are
greatly needed.

In all reports and comparisons, and especially in the tables of
averages, the character of the land surveyed, judged on the basis
of averages or percentages, is of primary importance, since this is
the principal factor determining the number and kinds of birds
that will be found nesting there. Two adjacent farms of the same
size may support the same number of pairs of breeding birds and ~
yet have few species in common, because one farm is upland and

’

REPORT ON BIRD CENSUSES, 1916-1920. 7

the other bottomland; one a dairy farm, the other devoted princi-
pally to grain raising; or because the trees of one are largely hard-
woods and of the other, evergreens. Or one farm may have a very
large bird population, while an adjoining farm of the same size has
few birds, the first having a large orchard or much shrubbery and
many trees, while the second has few trees or is intensively cultivated.

The majority of the censuses thus far received have resulted from
counts made on that part of the farm surrounding the house and
other buildings, including the garden, the orchard, and the lawn
with its shrubbery and shade trees. Here are many attractive nest-
ing sites and an abundant food supply, and here also will be made
most of the efforts toward attracting birds, by the placing of food,
nest boxes, and bird baths. This is the part of the farm, therefore,
where birds are most abundant.

According to the decennial census of 1910, the average farm in the
section north of Maryland and east of the Plains contains 108 acres,

e Less than 3years
+ 3 years or more

Fig. 1.—Localities from which reports on bird censuses were received for the five years 1916 to 1920.

of which 1.2 per cent, or about 1} acres, is orchard. The counts from
this section covered an average of about 76 acres each, including 43
acres of orchard, which represented nearly 6 per cent of the total
land surveyed, and on the above basis would be over 4 per cent of
the farm. To the birds the orchard is the most attractive part of
the farm. Since the farms on which these counts were made had
about four times the normal acreage in orchard, they must be regarded
as unusually rich in bird life.

The records deal principally with the 76 acres of the farm about
the buildings, and for the five years show an average population of
100 pairs of breeding birds. There remain unsurveyed about 32
acres of the more thoroughly cultivated parts of the farm that con-
tain little woodland and probably few birds. Judging from counts
made on farms that were largely under cultivation, the average bird
population of these 32 acres would probably be little, if any, over
20 pairs. For this five-year period, therefore, the farm of 108 acres

——_"

— es ee CU. OT

x 22

Bw

8 BULLETIN 1165, U. S, DEPARTMENT OF AGRICULTURE,

had an average bird population of 120 pairs, while in 1914 and 1915
the average was estimated to be 119 pairs. Fluctuations in the
number of birds per acre that occurred from year to year may be
noted in Table 1.

Table 1 summarizes the results of censuses taken on farm land in
this section for the five years 1916 to 1920. For the sake of the
rather interesting comparison possible and because conditions in the
eastern part were somewhat different from those in the western, this
section was divided into two parts—the Northeastern States, includ-
ing New England, New York, New Jersey, and Pennsylvania; and
the North Central States, those north of the Ohio River between
Pennsylvania and the Plains; and the results have been so tabulated.
Only four years’ records are included for the first-named division
because of the limited number of reports covering farm land received
in 1919.

According to the 1910 census, the farms in the Northeastern States
have, on an average, slightly over 58 per cent of the land improved,
and in the North Central States, nearly 76 per cent. Allowing for
a few acres of hay on each farm, the areas surveyed in both sections
have approximately 50 per cent of the land improved, making these
tracts above the normal farm in the proportion of the land that is favor-
able to bird life; especially when the large acreage of orchard repre-
sented is considered.

TABLE 1.—Results of bird censuses of farm land in the Northeastern and North Central
States, 1916 to 1920.

Northeastern States. | North Central States.

: “ = ote
| Aver- Aver-
1916 | 1917 | 1918 | 1920 | age, 4 | 1916 | 1917 | 1918 | 1919 | 1920 | age, 5
| | years. | years.

Average size of area covered by each | | | |
ot it 2 te ee Sa Seem acres..| 64, 79) 89) 61 73 | 64} 70} 57/116 | 90 79
VMN oc cr dnias ida cree ac cote 2 do: tS)" 48e) 57a, aOa) 46 55 | 48] 54| 46) 97); 70 63
MVOLCH ALG food ore, .c, «a /sieidis 12 2/6 d@e...a|> 29 8 8 4 6 2 2 MBN 0 1 4
inwoodland< 2-2. 225.2282 doss23} 11 |b 14 ey) 12) “14 7° 14 | “10 fell 13

In plowed land (field crops other |

EOAn iNay eo So ee gcres 2} 13) 137.|) 497). 12 28:)) »204) 29: 22 i, G7) e28 33

Proportion of the land covered in—

ROLOS So isldcnc cee cee cemene percent..| 75 | 72] 79] 75 or]? da ede (80) rOae | ads 79
Ouchard.< <2: .scigrist- atone ee bere pe) F ota: 9). Bhs 2 4 ae ciel 4
WioGdiand 34.0. kA Ao. tae 0.2 | 17 18 12 18 16 22,9" “20 18 CLP et 17

Field crops other than hay | | | | |
Ean eaters etieparse ae act per cent..; 20) 47) 551° 20 36u|) colt ke) oS Gayle ot 42

Average bird population on each area |
COMMKOM 45, aa te acter e Oue tee pairs..} 102 | 98} 85] 91 04 | 89] 90| 86 | 156 | 112 107

Average bird population per 100 acres |
on land counted... 5-2... -j..2s< pairs..| 159 | 124 95 |} 149 132 | 139 | 129 | 150 | 135 | 124 | 135

In the northeastern section this small amount of cultivated land
may be partly balanced by the relatively small proportion of wood-
land. .The census of 1910 indicates that the woodland comprises
27.2 per cent of the farm, but only slightly over 16 per cent of the
land on which counts were made was in woods. In the North Central
States, however, the woodland of the tracts counted was about 3 per
cent in excess of the normal as given by the census, which, in conjunc-
tion with the small proportion in crops and the large amount of or-
chard—the latter over three times the normal—makes the land sur-

REPORT ON BIRD CENSUSES, 1916-1920. 9

veyed very favorable to bird life. The woodland in farms is usually
in comparatively small lots, and the figures indicate that the average
bird population of such plots is nearly four times as dense per acre as
that of the land devoted to crops.

Under the designation ‘‘fields” there are included, besides the
land in crops, the area in lawns about the houses, driveways, pasture,
and meadowland. It is obvious that the remainder of the farm, the
part not included in the counts, must be largely under cultivation,
and will therefore afford nesting places for very few birds. Exact
counts are needed from this part of the farm, in addition to those made
on the land surrounding the buildings, to determine just how many
birds do nest there. If these are made as separate counts, their
interest and value will be increased.

The average farm in the Northeastern States contains between
97 and 98 acres, and the censuses here deal with 73 acres, leaving
about 25 acres unsurveyed. Most of these 25 acres are under culti-
vation, and returns indicate that under such conditions the bird
population is about 54 pairs per 100 acres, or 13 pairs on this section
of the farm. Since 94 pairs were found to inhabit the 73 acres
surrounding the buildings, the average farm of 97 acres would have
107 pairs of nesting birds.

In the North Central States the average farm contains 123 acres,
79 acres of which are covered by the counts, leaving 44 acres not sur-
veyed, which must be largely under cultivation. In this section we
find that such land supports about 71 pairs to the 100 acres; therefore
these 44 acres would have 31 pairs of birds. The 79 acres of the counts
were found to have 107 nesting pairs, making a total of 138 pairs of
birds on the 123 acres of the average farm.

The average bird population to the 100 acres on farms in the
Northeastern States is 111 pairs, and in the North Central States
112 pairs.

RESULTS OF CENSUSES FROM SOUTHEASTERN STATES.

Very few reports were received from the South Atlantic and Gulf
States, and, since only about half of them deal with farm land, the
acreage covered by counts is much too small to allow any deductions
regarding the ayerage bird population in this section as a whole.
Moreover, less than half the States of the section are represented by
these counts. Census returns indicate that the woods and improved
land of the farms in this section each represent between 46 per cent
and 47 per cent of the total acreage farmed, and that less than 1 per
cent is in orchard.

FLORIDA.

Reports received from Florida in 1916 concerned land which had
about 39 per cent m woods and 174 per cent in crops, and showed
less than one pair of breeding birds to the acre.

ALABAMA.

Land surveyed in Alabama in four different years averaged slightly
over 52 per cent woods, 1 per cent orchard, and 34 per cent in crops.
For the four years this land supported an average bird population

44125—23—Bull. 1165——2

10 BULLETIN 1165, U. S. DEPARTMENT OF AGRICULTURE.

of 126 pairs to the hundred acres. One tract of 40 acres, in 1918,
suffered the heaviest loss in the breeding population noted on a
single area. Several species found in 1917 were entirely absent the
followimg year, among them being the mockingbird and the brown
thrasher, each of which had been represented by two pairs, besides
several species of insectivorous birds. In 1917 there were three
species and four pairs of woodpeckers, and in 1918 not a woodpecker

was present.
TENNESSEE.

An average bird population of 107 pairs to the hundred acres was
found in Tennessee in 1917 on land that contained no woodland or
orchard and had 40 per cent in crops.

LOUISIANA.

Returns from Louisiana deal with land that was exceptionally
favorable to bird life, in the years 1916 to 1918, inclusive. A little
over 35 per cent of this area was in woods and more than 3 per cent
in orchard, while only 20 per cent was cultivated. The average bird
population for the three years was slightly over two pairs to the acre.

RESULTS OF CENSUSES FROM WESTERN STATES.

Reference to the map (Fig. 1, p. 7) will show that reports on bird
censuses from the western part of the country are very few indeed.
In this vast area stretching from the Plains to the Pacific physical
conditions are greatly diversified, and climatic conditions range from
humid on the eastern border through various degrees of aridity to the
humid region of the Pacific coast. Nothing more definite can be said
of the bird life of this area than that it is very variable. In all parts
of the country birds are inclined to concentrate in places where water
is available and trees and bushes offer shelter, and, judging from
present returns, this is especially true over the western part of the
country, particularly in the Plains region, where only a few species
nest on the open prairies.

Beyond the Plains, in the Rocky Mountain region, is presented the
additional problem of altitude, and here there is also much heavy
forest, where birds are far from abundant, as the bird counts at hand
show. The valleys, when not cultivated, are frequently arid and fur-
nish nesting sites for few species of birds.

The Great Basin, between the Rockies and the Sierras, offers many
interesting problems. Reclamation projects are bringing under
cultivation many thousands of acres of land formerly desert, and
changes in the bird life, both in species and in numbers, will result;
it is therefore very desirable that as many counts as possible be ob-
tained immediately from this region in order that material may be
at hand on which to base comparisons in the future.

For the Plains region from North Dakota to Oklahoma data are
too few and scattered to allow any generalizations, except that birds
are seemingly less abundant than in the more humid regions farther
east, and also that they are very unevenly distributed. There are
few extensive tracts of woodland, the trees being largely confined to
planted groves and to strips along the river bottoms, and here, where
water and shelter are to be had, birds are sometimes enormously
abundant. |

rs > a

REPORT ON BIRD CENSUSES, 1916-1920. 11

KANSAS.

Two series of records from Kansas are so suggestive as to warrant
quoting at some length. One is from Onaga, near the northeastern
corner of the State, well within the humid belt, and the other is from
the south central part, at Harper, on the Plains.

At Onaga counts were made for five years on a 40-acre tract, half
of which was planted to corn; the 4-acre lot containing the buildings
is bordered by hedge, and 6 acres of grove extend along two sides;
and there are 5 acres each of orchard and pasture. For the five
years this tract held an average bird population of 50 pairs of 24 .
species, or an average of 125 pairs of birds per 100 acres. In 1916
only the 10 acres surrounding the house and including part of the
grove and orchard were surveyed; but this small section held 37
— of birds representing 22 species, leaving only some 15 pairs of

irds to nest on the remaining 30 acres of this entire tract, only a
few more than on the adjoining open prairie. This 40-acre tract of
native prairie is somewhat hilly, with a small stream fringed with
trees and brush, boxelder, willow, white elm, and dogwood. The
average bird population here for four years was 13 pairs of 10 species,
a rate of 33 pairs of birds per 100 acres. (See Tables 2 and 3.)

TABLE 2.—Birds nesting on 40 acres about house at Onaga, Kans.

(Figures for 1916 refer to 10 acres only).

Species. 1914 1915 1917 1918 , 1920 1916
|

+) EGET LEA eva he) hy ieee a a ASE Seley: Sl ee Sel ey ee: | ie ae A oe
ON Lie gs gill EE IRE ai Ea Ce dE pee Baa a re a 1 1 1 2 | 1 1
PMOUTMNP MOVE. 2... 2. oet i Ledie. f5 ee tersd. Lees 3 8 art" 5 3 3
EPC IMOMres Petree ee So) OE wh 5 Bale ecb lc ene Pais cerowre 11M Lee! fe A See [i Sale ee

PPPOE CUCKOO. |. 2 Sahten ilo, 8 conan acne ddecns 3 2 1 ues 1
PElsyeWOOUPOCKER = 2. oo. 5. bo Sole coe sos PEE I BO.e S se Ae ee Pees eee
PU OMMBAWOUODOCKER. = 5.2% Da. )sce ©. Rice <ja<'a/s wrae be wesc |cee ocd aloe oot en's Bie dsc eel shs oe ote | eee
*Red-headed woodpecker . .....-.-..-- seen eee eee ens 2 2 2 i. | 2 1
ORCL Pees a ereee et ee ety PTE a A oe D if 1 1 1 1
Mrenilaywk> a0 e+ st itscirs. errs ei. Ji. loners? 54 4... so Iu Psk23. 33 Rese
BUPMPNN M2 ERE ay ee Se Sin Pas Sowc's' lc wo wes Sese- 3 1 1 1 1 1
eg ol eS te 2 oe ee ee oe ee Os 1 1 1 14] 1 1
aa art eee et ee be Pars ders ols come oo 1 1 al 1 | a6 Se brody 1
wo gl os S geieee Fe are US 5 A alae Met tee 1 2 1 1 2 2
SW RIINE.. See eee te ed.) SS SCUL Se, oswed i wisede Oke ily hee SA Seb e e ee eel ee eens Ll steeee te
PEM WATT COC DINCROIRG = sass os acc ve dacs ccceledeacecheeose- see EA eet re ad o£ Re ea ae 1 Sct Se
LEE IEC OLE Se See ee ee a. ee ee 3 2 1 2 2 1
“ALE DI TETENG) (250) 6) Coe ee i i a are ee eS 2 1 2 1 il 1

TEOUVEMIETACHIOL Se 0b hoo ecb eee ce eceacs oo he Sites = en et an, SI Ucn 3
ORBITS (2 ani fet FC SSE NE Se eee foe See Sey oe See nd 4% ey sy Ee BRS eS Poh
per CHten Latina meyer a tm wenger tA PA Aw lee c eine - ete Safer eeee ae, & Fa Tee
Grasshopper sparrow..........-...---.---- PEL. (8. 1G Rs oo 2 ee a Sk yee ae bee ee Pe eee os
PeeWee Moe Tee ly eee ee tae) tel ag. A bode aa ee reer 1 Pe
MiclunnEEnOwse es ete MIATA See aT. 1 pO i Fo 38
TET 2 2 SS BE es oe es eee Mee ere or een area [any eee vid 3 1 1
2a. Epis attra a od Sepals 2 abo Sale ple et Mt nr il in li ee ee Pee 5 (on (Re aco llntet ttle Dy eg
ipretamigecls 155441-.10. 30h ier thee de Lt | 3 | D435. At 1 de]; . a. be
20 TSN Ce cap ee Daina mites SiR is pee Renee re 6 6 | 5 7 8 8
cin VINOD oie ee as ois cela soce lacs wk ac gece deme 1 cede. | Wiestak! 1
EMA pre ae 2 ae oe ae oe oii aes 1 3 | 2 | 6 | 1
pricllenw- ayatrler ~ 3.2 Pesos ONT. esc aclevat os. 4 1 1 | 1} hl a eee fe 1
Manvisnd vehowtnroat.» i. - 2.4. bes. i seme pbex ce odi.daee Lie: cen | 1S ee ORS | ee ee eee
Rie et ie ei | ak ete Se ne ee oe ae leak ath alk mac's <i eget G2 1
yy) Blige SEAS ASI REA RTE eA ea 4 5 4 5 | 3
Bimemieanarasnon.) (ae eh ee) oe Sie ba 2 37 2 5i4 2
LE TSE Un Ta ee ee ea ee ees ea Se 2 2, I oe ees 3 2
Long-tailed chickadee. .... 2.2. 5.5.0.2200 5.22. eeek eet Me SPL ett Bb itso; =f Gh eres
DUCED Re OA REID Gear Ste a otic « dan dees cemee 1 1 1 2 1 1
Mereenmaregte. 1 YF. 5)1 5). och OBIT a EU Palisa 2 re eee

| |
Real aM DerOr species .222 2.2. on. b ce. oy te 26 | 22 | 24 | 24 26 | 22
Total number of nesting pairs................-- [iy 956 49| 40} 48 57 | 37
*Present every year. +Present only one year.

12 BULLETIN 1165, U. S. DEPARTMENT OF AGRICULTURE.

TABLE 3.—Birds nesting on 40 acres of prairie at Onaga, Kans.

ee a") Ge
Species. 1916 1917 1918, 1920 | Species. 116 1917
, un eh v Recoalnes
| || ri, ty)»
opehites no ee ih PO it ell ite 1 so ob le AM Nap Sc tl | 2| 1]
HMournine dove. 1222.07). 2 2s Tig 2 Fee Gta La) Aa RP || Stel) vired: 3.6.32 TRU a
+Downy woodpecker. ........... Tj a he fl ee @itbied Fo ae ase PT
+Red-headed woodpecker........ ate P12 : Nas | * ‘Brown torashers. (0 00-20% vo ee Be
Te als i454: 2553 9- e5a ts hs tau? sestgeaid | Petonserwrep.:.ct - Psu Lee ee Wa szP | 8
LO CGR aE = ery etre Ss oS [Deis |G) ake 4s || fLong-tailed chickadee. ......... Ve el oe
{Orohard oriole tte. hate L3I 98 L Ry | Bluebird... ..1.....2.00121...0-. | male
SR Fee Perey ae leecns — oO |
*Grasshopper sparrow.....-...... Bh ieee a UA se Pac Total number of species..., 10 | 9
*Lark Sparcow..6. . 43.2. <2) - 3 +e bed aa Total number of nesting |
PHO SPAIOW th 25.5 scene Be| a Ab wel a Lull POTS. ono ee cole roe 1 EZ
+Qwreinalls 3... eee LE Aa | est Pah| SEE: | | p Fa
*Present every year. +Present only one year.

Two tracts of 80 acres each near Harper show a similar contrast.
The first, on which reports were made in 4 different years, comprised
35 acres of alfalfa and sweet clover, 12 acres of grain, 15 acres of pas-
ture through which a stream runs, forming asmall swamp of perhaps 2
acres, and 15 acres in the orchard, grove, and garden around the build-
ings, besides which there was a l-acre grove of young catalpa trees.
On this tract the average nesting population was 122 pairs of 34
species, or 153 pairs per 100 acres.

The adjoining 80 acres consisted of 45 acres of prairie pasture, 2 to 4
acres of alfalfa, and the rest planted to wheat or cane. There was in
this case also a stream and tiny swamp that attracted a few red-
winged blackbirds. Two years’ reports showed this tract to be the
home of very few birds. The first year 16 pairs of 8 species were
found nesting; the second, 26 pairs of 9 species; an average of 26
pairs per 100 acres, a marked contrast to the first tract.

OKLAHOMA.

Near Norman, Okla., a count made in 1920 showed 31 pairs of birds
nesting on 40 acres. Of this land, 10 acres were prairie pasture and
the rest planted to corn, cotton, and oats. Two dickcissels and one
meadowlark nested in the pasture, one bobwhite in the oats, and the
other 27 pairs of birds in trees and bushes along the stream which ¢

flows through the tract.
TEXAS.

Near Taylor, Tex., in 1916 a tract of 104 acres, of which 45 acres
were in cotton and 35 acres in sheep pasture, had only 29 pairs of
nesting birds. From the following list it will be seen that most of
these birds nested in the 8 acres of trees and shrubbery on the borders
of a creek crossing one side of the tract. The pairs of birds found
were as follows:

Killdeer, 1; bobwhite, 1; mourning dove, 1; red-bellied woodpecker, 1; scissor-tailed
flycatcher, 2; Acadian flycatcher, 1; cowbird, 2; orchard oriole, 1; bronzed grackle, 2;
lark sparrow, 3; cardinal, 4; painted bunting, 1; mockingbird, 5; Carolina wren, 1; Eng-
lish sparrow, 3.

Near Paris, Tex., in 1916, 80 acres of shrub-covered pasture showed
an average of 129 pairs of birds per hundred acres; and several tracts in
the vicinity of Fort Worth the same year had an average of 120 pairs
per 100 acres. No data are available concerning the bird population
of the plains region of Texas.

REPORT ON BIRD CENSUSES, 19161920. 13
MONTANA.

From Montana may be cited two reports that show an interesting
diversity of bird population within the borders of a single State.
Counts were made on 40 acres of park land belonging to the city of
Missoula in the years 1915, 1917, and 1920. In describing this tract
in 1915, Joseph Kittredge, jr., says:

The park is an isolated and specialized association for the upper bench, and the hills
around for several miles are open and treeless Transition Zone prairie country. Still
farther back is the coniferous forest; hence in this area there is a concentration of species
which are typical of the creek bottoms throughout the Transition Zone of the region.

On this area in 1915 there were found nesting 59 pairs representing
20 species; in 1917, 58 pairs of 19 species; and in 1920, 100 pairs of 25
species.

In contrast to this, in 1916, near Fergus, Mont., a count on 80
acres of sagebrush prairie found only 8 pairs of birds representing 5
species, 1 pair to 10 acres, almost exactly agreeing with the count on 40
acres of native prairie near Missoula in 1915.3 A mile and a half away,
in the trees and bushes along the creek, birds nested abundantly, but
no count was made in that section.

NEW MEXICO.

Two counts made by J. K. Jensen in 1920, in the vicinity of Santa
Fe, N. Mex., are of interest, because they indicate somewhat the differ-
ence in bird life between the cultivated land and heavy forest of the
region; but being at different altitudes they are not entirely compar-
able. The first was made on 106 acres of the land of the United States
Indian School, near Santa Fe, at an altitude of 7,000 feet. Of this
land, 12 acres, or about 11 per cent, was uncultivated, covered with
sagebrush and cactus, with a few junipers. The remaining area is
divided as follows: Buildings and campus, 27 acres; orchard, 4 acres;
garden, 4 acres; wheat, 16 acres; corn, 25 acres; and alfalfa, 18 acres.
This indicates that a large part of the area surveyed was under irri-
gation, and water always helps to attract birds. On this 106 acres
were found breeding 121 pairs of native birds, representing 22 species,
besides 100 pairs of English sparrows, a total of 221 pairs of birds.
» This is an average of 114 pairs of native birds and a total of 208 pairs

of birds per 100 acres. The following list shows the species sth the
number of pairs of each: 7

Killdeer, 1; scaled partridge, 1; desert sparrow hawk, 1; flammulated owl, 1; Cas-
sin kingbird, 2; Say phoebe, 3; western wood pewee, 4; desert horned lark, 4; western
meadowlark, 4; Bullock oriole, 1; house finch, 50; Arkansas goldfinch, 13; pine
siskin, 1; western vesper sparrow, 4; western chipping sparrow, 8; Brewer sparrow, 8;
black-headed grosbeak, 1; western blue grosbeak, 1; barn swallow, 1; Sonora yellow
warbler, 2; western robin, 6; mountain bluebird, 4; English sparrow, 100. -

The other report deals with 90 acres of the Santa Fe National
Forest, situated at an altitude of 8,000 feet. This land extends
for about two-fifths of a mile along the Santa Fe River, and 1,000
feet from either side of the stream. The canyon bottom is covered
with brush and aspens; and the slopes of the mountains, which rise
quite abruptly for about 3,000 feet, are heavily forested. In this
area were found 48 pairs of 20 species, all native birds. This is ata

3U.8. Dept. Agr. Bul 396, p. 9.

14 BULLETIN 1165, U. S. DEPARTMENT OF AGRICULTURE.

rate of about 53 pairs of breeding birds per 100 acres. Mr. Jensen’s

description of this territory is interesting:

This being my favorite hunting ground, practically every nest mentioned was
located. The east slope of the canyon is covered with pine and spruce down to the
level bottomland. All thrushes were found on this side. The west slope is covered
with oak in which the evening grosbeaks and juncos were found. This is virgin
country with numerous signs of bear, mountain lion, and wildcat.

The following are the birds found breeding:

Red-naped sapsucker, 2; red-shafted flicker, 2; western wood pewee, 1; western
flycatcher, 3; Traill flycatcher, 1; long-crested jay, 1; western evening grosbeak, 2;
red-backed junco, 2; sage sparrow, 6; western tanager, 1; violet-green swallow, 8;
least vireo, 3; Audubon warbler, 3; water ouzel, 1; Baird wren, 2; pygmy nuthatch, 2;
pecan solitaire, 2; Audubon hermit thrush, 2; western robin, 2; chestnut-backed
bluebird, 2.

WASHINGTON STATE.

Near Pullman, Wash., four counts were made in 1920 by students
of the State College of Washington, under the direction of Prof. W. T.
Shaw. These counts covered a total of 162 acres of land divided as
follows: Woods, 5 acres, or 3 per cent; orchard, 13 acres, or 8 per
cent; and fields, 144 acres, or 89 per cent; with 79 acres, or 49 per
cent of the whole area, under cultivation. With the exception of 4
acres of garden, the land cultivated was in grain, mostly wheat.
On these 4 tracts, apparently not continuous, 184 pairs of birds, in-
cluding 5 pairs of English sparrows, were found breeding. This is
an average of 114 nesting pairs per 100 acres.

The only report from the northwest coast region is from Gig
Harbor, on the upper reaches of Puget Sound. Here, in 1916, an
80-acre tract was found to shelter 144 pairs of nesting birds, repre-
senting 48 species; and the next year the same land had 185 pairs
of 43 species. Conditions on this tract were exceptionally favorable
for birds, so that these figures can hardly be taken as representative
of the region as a whole.

CALIFORNIA.

Probably no State has a greater diversity in its bird life than Cali-
fornia, with conditions varying from the humid coast to the deserts
of the interior and to the high mountains. No generalizations con-
cerning the bird population can be made until counts have been
made on a very large scale. No reports have yet been received from
the northern part of the State nor from the sections less favorable to
bird life. All counts received have been made on cultivated land,
except those from the region of San Francisco Bay. These show a
good deal of diversity, as will be seen from the examples quoted.

A record density of bird life is found in Golden Gate Park, San
Francisco, where conditions are unusually favorable. Across the
bay on 20 acres of Strawberry Creek Canyon, a part of the campus of
the University of California, there were found breeding, in 1916, 93
pairs of birds, representing 30 species. None of this land was culti-
vated and much of it was wooded. ‘The birds found were as follows:

California quail, 3; screech owl, 1; red-shafted flicker, 2; Anna hummingbird, 4;
Allen hummingbird, 2; olive-sided flycatcher, 1; western wood pewee, 1; western
flycatcher, 4; coast jay, 1; California jay, 4; California purple finch, 1; willow gold-
finch, 1; green-backed goldfinch, 2; Santa Cruz song sparrow, 10; San Francisco
towhee, 9; California brown towhee, 5; black-headed grosbeak, 1; lazuli bunting, 2;

=. atom

REPORT ON BIRD CENSUSES, 1916-1920. 15

cliff swallow, 3; warbling vireo, 3; Hutton vireo, 1; lutescent warbler, 4; Macgil-
livray warbler, 2; pileolated warbler, 2; California thrasher, 1; Vigors wren, 4; plain
titmouse, 1; intermediate wren-tit, 5; coast bush-tit, 5; russet-backed thrush, 8.

Near Fresno, in 1920, a 40-acre tract showed only 18 pairs of birds,
including 3 pairs of English sparrows. Of this land 25 acres were in
vineyard, 3 in orchard, 6 in alfalfa, and 6 in pasture. The 12 species
found were distributed as follows:

Killdeer, 1; valley quail, 1; barn owl, 1; Pacific nighthawk, 1; western meadow-
lark, 1; Bullock oriole, 2: house finch, 3; willow goldfinch, 1; western blue grosbeak,
1; California yellow warbler, 1; western mockingbird, 2; English sparrow, 3:

At Banning a census was made on 40 acres, about half of which was
in orchard and the rest mostly in grain, with three small gullies
filled with herbage. This tract showed just 1 pair of birds to the
acre, 23 of the nests being actually located. There were no English
sparrows, and the 15 species of native birds were:

Valley quail, 2; mourning dove, 6; Texas nighthawk, 2; black-chinned humming-
bird, 1; California horned lark, 2; Bullock oriole, 1; hooded oriole, 1; house finch, 2;
willow goldfinch, 1; green-backed goldiinch, 7; lark sparrow, 5; western chipping
sparrow, 1; Anthony towhee, 6; California shrike, 2; yellow warbler, 1.

A count on 68 acres near Buena Park, Orange County, showed the
bird population in 1920 to be only a little over one pair to 2 acres.
Of this area, 33 acres were in barley, 12 in beans, 5 in garden, and the
rest in pasture or uncultivated. The 16 species and 39 pairs were as
follows:

Killdeer, 1; valley quail, 7; mourning dove, 3; barn owl, 1; burrowing owl, J; black-
chinned hummingbird, 1; Anna hummingbird, 1: western kingbird, 1; California
horned lark, 2; western meadowlark, 6; Bullock oriole, 2; Brewer blackbird, 2; house
finch, 4; green-backed goldfinch, 3; Lawrence goldfinch, 1; California shrike, 3.

Escondido is the point farthest south in California from which counts
were received, and one was made here in 1918 on a tract of 80 acres.
About 25 acres of this area were devoted to hay, and the rest was
divided between fruit trees, brush, and other trees, mostly eucalyptus.
Here were found 129 pairs of nesting birds, but only 18 species:

Valley quail, 5; western mourning dove, 27; black-chinned hummingbird, 3; Anna
hummingbird, 1; Arkansas kingbird, 2; black phoebe, 1; California horned lark, 12;
California blue jay, 1; western meadowlark, 10; Arizona hooded oriole, 2; house finch,
35; willow goldfinch, 5; Arkansas goldfinch, 10; western lark sparrow, 5; Anthony
towhee, 7; phainopepla, 1; California shrike, 1; western mockingbird, 1.

SOME NOTABLE BIRD-CENSUS RESULTS.

Geneva, N. Y .—An extensive series of counts from the vicinity of
Geneva, N. Y., for the three years 1916 to 1918, made by Otto Mc-
Creary, seems worthy of rather detailed presentation. (See Table 4.)
Comparison of the results obtained here with those of New York
State as a whole for the same years indicates to some extent how
sample areas, if representing the average conditions for their respec-
tive localities, make generalizations possible, but shows also that
many localities are needed to determine the final averages. When
considering the results, it is to be remembered that the figures from
the State as a whole include those from Geneva and that all the
= data deal with land wiica is or mignt be farmed, no reports

aving been received from the mountain regions of the Adirondacks
and Catskills.

16 BULLETIN 1165, U. S. DEPARTMENT OF AGRICULTURE.

A greater decrease in the number of birds per acre is noted in 1917
than in 1918; reference to the table shows, however, that the decrease —
in 1917 is accounted for by the difference in the character of the land
surveyed, while that of 1918 is a part of a general decrease through-
out the eastern United States. One plot of 92 acres, reported upon
all three years, shows in 1918 fewer individuals of certain species
that figure in the decreases elsewhere (see p. 28).

TABLE 4.—Comparison of results of bird censuses taken at Geneva, N. Y., with all those
from the State of New York.

Geneva, N. Y.

1916 1917 1918 Average.

| Acres. |Per cent.| Acres. \Per cent.| Acres. Per cent. |Per cent.

Areas covered by censuses..........-... 1715 Ry nel ede | ESO blo etc oe | ay fae spin EE ee Go
mn MeldSeLear’ 1 Si Roa 75 48 943 72 1, 873. |] 80 67
AmrOrchards.one2e . Sc ny etadts == | 45 29 145 11 150 — | 9 16
PE WOOUS ee co tie ae 35 23 219 17 189 ll 17
lowed land: 22 Fs er. Shs eto. 68 44 895 68 1,493" | 70 61

Nesting birds counted: | Pairs. Pairs. Pairs.

Native species........... POSThR! Boat. SST Bosgh it: eI 1 das 12 VARIN, See
POR Sears coc sath oy nce bee oct 7 Age eens eee 1415, + |e: [yb 270 he te berendecaaeee
Bird population per 100 acres and per-
centage of total: | | | |
INAEINE\DITGSS\~ dja crc Bac = cece oe 132 |. ates sr a 1 Pe a IB ys
Wiispoctes.uii). Ss Slee CR HAZ PARE. O22 Bo SS. 19! EWES REE See
RODIN. Ses Pe. £39 eee 27 19 | 7 § Sart i il 13
CE a eg aA I 4 3 | 1— 1— 1— | 1— 2—
Song Spalrow....:.<ser sesefaene | 15 11 15 1 oh ag 23 17
Chipping sparrow... 2:22.52 5. %. 19 13 4 5 3 4 7
English sparrow............... 10 7 5 6 | 7 9 7
}
New York State.
1916 1917 | 1918 Average.

ai Per cent.| Acres. Per cent.| Acres. Per cent. |Per cent.

’
PTGICNUSS 32 Ae ars tess he cient teen oS 560 66 1,277 fi 1, 507 84 7
SOR CHS eo eta obs eee 91 | 11 186 10 150 8 10
INLAROGOS fe See on te <2 cob cat. Somatee 200 | 24 330 18 203 11 18
Pidwed' landos: 2 fU 2 se seee 208 24 1, 002 56 1,198 64 48
Nesting birds counted: Pairs. Pairs. Pairs.
INS ELVC SPPCIOS S298 pois ic Bin fi sanete 1 a4 | ta a LOLA. |. Be dey oz 8 SSA hd ois epreall b eens ge
RUS POCIGS. ta < doe Ab ok sees oc ae 1S 4S pea go Pog iS sy ierwele TD OOUs | « «oes < am. [eee
Bird population per 100 acres and per-
centage of total:
INGERVG DIDGS~... 2 et ooo eee Ls) Pee Se LOT | 2 Seas 17 |aleseck Selo Ree
All: species. s.22: . 2302 SaaS 1B 3.6 S53 45- A959} C4. okT B5 il 2 eorceeac|c see eee
GOI... ae. oe eee re ce 23 14 12 10 10 12 12
Catbind <0 43). wera see te ee 7 4 3 3 2 2 3
Sonegisparrow. fi bik 16 10 16 14 17 20 15
Chipping sparrow..........--. 11 7 6 5 4 5 6

BPMeHsh \Sparrgw. ose. soe oe ans 8 5 7 6 7 8 6

Referring again to the 1910 census, we find that in the State of
New York 191 per cent of the land in farms was woodland and 644
per cent was improved, of which slightly under 3 per cent of the
total was orchard. The 16 per cent of orchard in the land surveyed
about Geneva is thus considerably in excess of the normal for the
State; but this is partially balanced by the low amount of woodland,
here more than 2 per cent below the normal. Plots of woodland
containing from 12 to 95 acres were counted but were not so rich
in bird life as woodlots usually are, the average for the three years
being only 87 pairs to the 100 acres, less than half the average found

REPORT ON BIRD CENSUSES, 1916-1920. 17

forsuchland. This, together with the a amount in crops (plowed
land), nearly 60 per cent, accounts for the fact that here, in spite
of the excess of orchard, the number of birds per acre is less than for
the State as a whole or for the Northeastern States. For the entire
State the total amount of improved land covered by bird censuses
is not far below the normal, though the proportion of orchard is very
large, and the woodland also is a little below the percentage given
by the official census of 1910. The average bird population for the
State agrees very closely with that of the northeastern section for
the same years, that for New York State being 122 pairs and for the
entire section 126 per 100 acres; at Geneva the average for the three
years is just one pair to the acre.

Viresco, Va.—The longest series of bird counts on file concerns a
tract of about 55 acres at Viresco, Va., not far from Washington,
and extends over 10 years. This tract has the added interest that
the experience gained in making the earlier counts here formed the
basis for the 1914 circular of instructions for taking a bird census.

The land includes 21 acres of woods, 18 of pasture, 5 of land plowed
for grain and garden, 3 of brushy hillside, and the remaining 8 acres
in trees and brush along a stream that meanders through the place.
Most of the cleared land had been cultivated up to a short time before
the area first came under observation in 1907, and it was then growing
up to brush. At that time the underbrush in the woods had recently
been thoroughly cleared, but it has since grown back, and the small
trees and brush along the stream have grown considerably. One
plot of 3 acres, formerly cultivated, has been allowed to grow wild,
and in midsummer about half of it is an almost impenetrable tangle
of brush overgrown with catbriar, honeysuckle, and wild grape.
Since about 1916 a large part-of the chestnut trees have died out
of the woods, but the dead trees have been cut each winter, giving
a chance for the other species, principally oak and tulip, so that
there has been little noticeable thinning of the woods. From 1916
to 1918 about 4 acres of pasture were set to orchard, but as yet the
ee have not made sufficient growth to alter the character of the
and.

Throughout this period birds have been strictly protected, but

the only efforts toward attracting them have been the erection of a
small martin house (scorned, however, by the martins, though several
times occupied by bluebirds or house wrens), and recently two or
three wren houses. No special feeding has been done at any time.
The counts on this tract show a steady increase in the number of
birds breeding until 1918, when there was a decrease of over 20 per
cent; the average of 1916-17 was fully recovered, however, by 1920.

An excellent example is here furnished of what protection alone
can do toward increasing the number of birds nesting on a given
area. The growth of the bird population has been greater than
that warranted by the increased supply of food and shelter; it seems
oe rs that it has resulted in part, at least, from recognition by the

irds of the security of this tract as a nesting place. Unfortunately, it
has been impracticable to make counts on the adjacent territory and
thereby to ascertain whether any decrease has occurred in its bird
life as a result of the increase on the tract surveyed.

44125—23—Bull. 1165——3

18 BULLETIN 1165, U. S. DEPARTMENT OF AGRICULTURE. — zr

During the 10 years 51 different species of birds have nested
on this tract, the number present in any one year varying from 27
to 39, and the number of nesting pairs from 48 in 1911 to 105 in 1917,
the maximum to date. (See Table 5).

TABLE 5.—Birds nesting on 55 acres at Viresco, Va.

Species. 1911 | 1912 | 1913 | 1914 1915 | 1916 | 1917

Bopwiite sas). 61 hk ie ee ORE ee RE ce | nee } 1
Mommie dove:: 8005-2255) 4050: Posed oot oes be OS ake rece all 1
TDCHECON OWL, . flo de wets ob ae Seb! ee ei et SS ORs [ete idee 4

Wellow-billed: cuck00: ..22 .2.. 28 s-cec~ 8.24 cles se | aera ey eg a | 25g. Yee eS Rees ie ttt 1 | 1
Hiniry woodpecker... ._...2....---.:-~- 1

1
Dowiiy woodpecker-...£50. .2.nihiae2 - - 1 1} a he. 1 1 1
GON s Se SES a Oe Oo ee ee 1 1
Wihinpoorwalls ! 28524245. Fe2 25. $525. 1 1 he pada es ‘be 1 2 2
Ohimneyswilht con.) 2c) ye ase pee lel~ 43/867 <
FAC NP DITO... Jxicine ticks 2nd sem aol eee ee ae 1 ae an (a | (ye ed (a 2
TCTATU CY it Sep RM eS a Ee Oe een Poy fe we SP it )| LOS Saba e bbtebcab
Crested fiviGRtCHOr 4.34655 Sapa eee oo 1 |

see eee

set eee

1
1

*W ood pewee.....-..-. 2 |
| 1

tMeadowlark.......

tOrchard oriole

tPurple grackle
Grasshopper'sparrow.s5 (i. 2.5 .220020..82 1

CHPODING SPAatlows foc... od eaatuiceree cit eee

BUN OLGKSDALTOW Shea. fsa d 0. sat ea selec 3

*Song sparrow. ....- Rac feblad: oo~ SEtEEE A 6

RONG WITT Home cts tects 8g sf aleacac bale Geeine cess 2

sOanginale fee eos efi). Se ir 1

PGE RO IMG se 8 ea he a 3

1

1

2

1

1

1

i MW Iii al |i wart (Py ma

CATIOE LAN APOE. Mees ae oe ees tees
*Rough-winged swallow.............-.--
IOU-=BYVICd VALCOs. c= care soy ces cccencense ss
Yellow-throated vireo................-.
WTC-Y CG VINED sas so oe Se Se
Black and white warbler...2..........-
TMOrMN-ea tine Warbler: bs Ao. 50. aotelb oie ots de s| yeee|t oes.
RDM AVCAL OLED. 5 hae cb eee Saco cones qlee se Paloeete (ae 8
|

Melliwwvatblor:sto-b a. telah. shoe ck oe aA CIEE Reale. aece Stee e
OA CT 02400 Cie Bene Cerro t= eae 3 | 4 4 | 6 | f
PlLeuisiana water-thrush. 22 _.02..322..72 ji, Sree (ee eee ee ae ase fens ced [Sean Sed [eee te!
*Marviand yellowthroat.:.-.....-.-..<.- 4 |
“ACN AT ove 20) 2 5 (e a cam. et SRN ra 2 |
1

1
ENOHSe waren 284 bt te ht cb Se cle! 5a Wes 2
1 1

Total number of species.........-.- 27 fgg: | * gary oe)? "ga 36
Total number of nesting pairs.-.-. lo 4 48: | 158 63 74 | 81] 9

* Present every year. y+ Present only one year.

Rantoul, Ill.—On a 400-acre tract near Rantoul, Il., counts were
made in four years, from 1916 to 1920. There are two small orchards,
together amounting to about 5 acres, with a garden near the house
and hedges and large trees about the buildings. Of the remainder
of the tract, about 300 acres were planted each year in corn and oats
and 50 acres were in permanent pasture and meadow. The birds
found breeding here have varied from 231 pairs of 35 species, to 340
pairs of 48 species, averaging 293 pairs and 42 species on the 400 acres,
or 73 pairs per 100 acres.

REPORT ON BIRD CENSUSES, 1916-1920. 19

In 1918 the count was made on the 160 acres of this tract that
contained the buildings with surrounding trees, all the garden, and
one orchard. Ninety-eight acres were in corn and the remainder in
pasture and meadow. This count found 152 breeding pairs of 26
species, including 12 pairs of English sparrows, an average of 95
pairs of birds to 100 acres. This 1s a rather small bird population,
but comparing these figures with those in other years, it is found that
on the remaining 240 acres there would be only about 140 pairs of
birds nesting, an average of 58 pairs per 100 acres. As regards the
number of breeding birds, the conditions on this farm would probably
be typical of many thousands of acres in the grain-raising States
of the Middle West.

Kerrville, Tex.—An interesting series of records from south-
central Texas, near Kerrville, covers the six years 1914 to 1919.
This land is not 9n the Plains but in the broken country which marks
the transition from the high Staked Plains to the low coastal plain.
The country as a whole is characterized by rough limestone hills
broken by numerous small rocky canyons densely covered with
scrub, and has some springs. The counts made here were on 80 acres,
of which about 35 were under cultivation, including $ acre of orchard
and 1 acre of garden. The character of the land is best described in
Howard Lacey’s own words:

My house is situated on the point of a hill at the junction of two narrow canyons,
one coming in from the west and the other from the north; below the junction they run
south until they join Turtle Creek (a tributary of the Guadalupe River) after crossing
the main road going up and down that creek.

The west canyon, which averages about 100 yards wide, and most of the valley below
the house (from 200 to 300 yards wide) are in cultivation wherever they can be culti-
vated and are generally in oats, corn, and sorghum; there is also a small garden and
orchard. A little creek winds down the valley now on one side now on the other, and
is subject to overflow and at times is nearly dry but never entirely so. A small irri-
gation ditch which is taken out of the west canyon is brought round by the house and
then joins the creek again.

Both creek and ditch are fringed with brush and about one-third of the valley is
given up to thicket and small groves of trees.

The valley is shut in by steep hillsides about 100 feet high, like the sides of a box,
so steep that one has to use one’s hands to climb them in most places, densely covered
witb small trees.

An exact enumeration of the black-chinned hummingbirds and
cowbirds was found impossible, the latter being here very numerous
and destructive to the smaller passerine birds, few nests of which are
found without cowbirds’ eggs. This ranch had as yet no English
sparrows. During the six years 45 different species of birds were
found nesting on this tract, 28 of which were present every year.
Exclusive of the hummingbirds and cowbirds, the bird population of
this tract averaged 147 pairs per 100 acres. (See Table 6.)

en

i a a a ———

| 20 BULLETIN 1165, U. S. DEPARTMENT OF AGRICULTURE.

TABLE 6.—Birds nesting on 80 acres near Kerrville, Tex.

: Species. 1914 1915 1916° | 1917 1918 1919

ee oe ea

NGKAS DOWWRNUGE- a6 ee cece aac eae nsec ee emer 1
*W eStiern MOUTHING Goveced se o7- ease. dts. fe sask 3
PB IACK VUGUTO os oe sete os doe Sb cis Peele Sas oo fioe' Sen chllbawede facie eet ce| in hamel |. cece deca cee eee
WQoopeN hawt. =k oO. VRE OT 2c BERLE OS TERE ed Chae a creche PUSSIES oe (bcd. Aetate

PBICETIISCECCCL OW Lad Bed cte a ous pels ete 15 EIS oo pion Fintan empties
*California cuckoo........... Ree eee eee eee ae eee 4
*Toxas woodpecker . sw: 1: ste take cee. sige essesbdads 1
POLI RaW LLU SW COW a orn ox od oclnin die Siataimin Sie lenin o.oiSiess ae Tae 1 1
*Black-chinned hummingbird.................-2...... () (1) (1) (Q) (Q) (1)

AUReStROity CALGN CMe a.m. .oe cscs te Soe = Sos oae ba caleeereieee 1
PASh-phnrosted flycatcher... ccs actecte- facwonte ce sees
* Wood peweestsu: 2... ssittoue ss Didvs.: sate. 4
Meagan ily CAalChel: cacnwacce soem eda s cataseme neces
FCOwpird K55..8 2.2.21. Fie SE Ia (2)
One ardlOmolese vance tae nck nm ac ce ietea ceadeneotis arse
4 PMRKASAS POUMNCH 5. cote eee te ate sore eee oes 1
| * Western lark sparrowis::+) -<pel-$ sot. ngesses Se. tee
| ED daar SWALLOW ccnscccas cnc tect Go oes secheare ceric

Mel SPATFOW 053425. 6 SLR PAG SIS SS

ESOCKESPALLO Wee ooo e oe cotesins sets + cere rageueee © =a
i eGrayetaned enrdimal.2 Css sctet. ee Lee
j *VWoestern Dlue erosheak 2..2,2t.cj(4. 250s. ce bs 8250. 2
I MITT SOROUMUMI Secs cand ccm co diage ma yoteisnine See Bae tate

: Painted Hunting 122 4 22. SASSI AISE REL Ee S-

rr

ro
wo
4
—
hoe EH
Yad
i )
rd

ADE ROR WWONNrODRPHAOOO=I

eee er eee

5

4

5

0

4

4

2

1

a

2

4

i
*Summen tanager.....- 9... -2.2. 058 bein tat ee ane eee 3
Je UERY ojo 042) 06 1 A a ne a Sesleri ata da 1
PEM ACen OCU COM = ante oe <a cenie yore nainise Biaerme das ecu ace | 6
3

1

2

3

1

4

4

2

1

1

6

ry

3

2

2

WOINwNfLWOW PR SW noe
—

BME O Wen OAbed VALCO NS: soos oo cclwtcdacae oaleiem|co ate |
Black-capped wiheOss 2. sy cco. See eee ens eee oe |

AWVEMLG- CVE vireOrs: Coss. 203 ARMIES S es ooh shee |
*Black and white warbler....-.......22.2.2.20 00. ae
PATA ANAL Ola. (sec sete ye mieied vf, ceie ek spot ba EEE
*Golden-cheeked warbler...=.--..-.--cc-cse-s-sececenn
POM I Ckay WAL DLCl | cineca cet etcacecoreaencccee oe ee
hate ses tae ort ors Tee. Le. Te ee LAS
EGG eT PUI Cee a. mart fe cyereiclcreatd ayes ayy Sh ced poe Meta sedate |
KORINE WECM Gat ce x sem ao ke cies aie de) etn mitawe atte, 2 oc
SCALOMME WHEW ese F5e oo. Oooh abs fone sa Sere ee eee
HTERASHWIENY Sos nobis HUGE Ses SEL Va |
PNOUMG Ele PUDITLOUSES ccicinractaystok perce emi meee tales aeretan eee
EE POUS CUNCKAGCE 0. oon oon eS emesis |
Bloepray- pnatcatchers 2225. aL See | Reidel il hd al WARE Se SSeS i
SEI EI lene of ois ches, oie Sieicis aeinre Aaose tipi cohen Mme om os ote aie fee eras | Jo SESE eae 1 2

Motal mum ber Of SPECIES co occu sess ern cans ah ac | 38 39 | 42 | 36 | 34 34
Total number of nesting pairs...........0.s.2-- | 110+ | 108+ | 159+ | 127+ | 106+ 101+

*Present every year. + Present only one year. 1 Several. 2 Common.

Concerning the changes in bird life which have taken place in this
region during his residence there, Mr. Lacey made the statement
recorded in Table 6 in 1914.

As to changes in the bird population, I have lived here since 1882 and do not think
that there are fewer birds here now than there were then, but some species are scarcer,
and one (the white-necked raven) has left us entirely and gone, I suppose, farther west;
it was ccmmon here formerly, but the crow has taken its place. The crows came 1n
abovt 1897, which was the last year that the ravens nested on Turtle Creek.

Bobwhite is much scarcer than he used to be, but is gaining ground again the last
year or so. The green heron is another bird that is not so common as it was a few
years ago, and purple martins are scarcer than they were, owing possibly to the fact
that people won’t take the trouble to put up boxes for them on account of the English
sparrows taking possession of the boxes as fast as they are put up.

The sparrows came to Kerrvillein 1897. The lazuli bunting has nested in the button
bushes along our little creek, but I have not seen one for some years. Wild turkeys
increased considerably during the last three years, owing probably to very favorable
Lreeding seasons; I am afraid that they will not do so well this year, as we have had
many hard rains this spring.

A bird that seems to have left us is Mearns’ quail; it was never very common and
kept to the rough country, never coming down to the fields as far as I know. Com-
paratively few quail are shot here, and it is rather hard to see why they should decrease

REPORT ON BIRD CENSUSES, 1916-1920. 21

in number; possibly overstocking the range with cattle, sheep, and goats had some-
thing to do with it, and the long drought of a few years ago helped to diminish their
ruber. I think it quite possible that they migrated in search of better conditions,
and I don’t think, as some people here do, that they just died out.

Raton, N. Mex.—A bird census on a tract of 160 acres near Raton,
N. Mex., at an altitude of about 6,500 feet, was taken in 1916 and
repented in 1920. This land is prairie, and the nearest timber is 3
miles away. A small creek in which there is water throughout the
year crosses the tract, and the crops are all irrigated. In 1916, 12
acres, or 7 per cent of this tract, were under cultivation, and 78 pairs
of birds representing 13 species were found breeding. In 1920,
with 50 acres, or31 per cent of the land, in crops, the number of
birds was 97 pairs of 12 species. Here the bird life has increased as
more land is put under cultivation, while in the more humid sections
of the country the reverse is usually the case. Additional food
supply due to the raising of more grain may have been the chief
factor in this increase in the bird population, since in 1920 there was
a colony of 20 pairs of cliff swallows, while in 1916 none of that
species was present. This species feeds extensively on the insect
enemies of grain and alfalfa that had doubtless multiplied with the
increased acreage in these crops.

RELATIVE ABUNDANCE OF CERTAIN SPECIES.

The study of the density of bird life has not been continued long
enough, nor have bird counts been made on a sufficiently large scale,
to learn definitely the relative abundance and distribution of indi-
vidual species. To see what could be learned even from the data
available, the following 10 widely distributed species of native birds
were selected for special study: Bluebird, robin, house wren, brown
thrasher, catbird, song sparrow, chipping sparrow, meadowlark,
kingbird, and flicker; with these were included the English sparrow
and European starling, the latter still being confined to the North-
eastern States throughout the period covered by this report. Inter-
esting but by no means final results were obtained, and the returns
of another five years may completely overthrow them.

The accompanying table (Table 7), dealing with six of the most
' abundant species in the Northeastern and North Central States,
shows for each, on the basis of the returns, its percentage of the whole
number of birds reported, and the average number of breeding pairs
per hundred acres. In figuring the number of pairs of birds per 100
acres, the nearest whole number has been used and a plus or minus
sign affixed. This table should be studied in conjunction with that
showing the character of land on which the counts were made (see
Table 1, p. 8), since there is a direct connection between the kind
of land, crops, ete., and the species and number of birds breeding.

22 BULLETIN 1165, U. S. DEPARTMENT OF AGRICULTURE.

TaBLE 7.—Relative abundance of the six species reported most abundant on areas sur-
veyed in the Northeastern and North Central States, showing the percentage of the total
bird population and the number of nesting pairs per hundred acres.

Northeastern States.
Species. [> ae aa | eee:
| Aver-
1916 | 1917 1918 | 1919 1920 age.
Pers |OUR era | a eer Per Per Per
Relative abundance: | cent cent. cent. cent. cent cent.
13/0] 0) 0 BOR A eee AAA 2 Se ee ae SERGE, ac 10. 4 10.8 | 8.9 4.0 dao 8.3
WALD fn et a eeee kB RUS SR a 2.1 251 | 1.5 105 ie tT
Song SPaLhow - «28 ds =. g¢aaets- sf[d-< bs fe eek see E -| 6.7 | 10.8 11,3 3.3 6.4 ted
DTD PUES DALlOW, te its teste bes coe cee bs widela cetera 5.3 | 4.1} 4.1 Darl 4,2 3.9
Meadowlarket:. sa eSt5- JG. Sig OE. 1.8 1.8 | 0.7 0.4 0.5 1.0
Hinglish SPALOW weds once oe Se oc ok sq De cb Dba =o 5.4 6.4 | 4.9 1 BY; 2.8 4.3
Average population per 100 acres: Pairs. | Pairs. | Pairs. | Pairs. | Pairs. | Pairs.
AT iit lak pl ener alah AP LO pm [ae thee a “a Ns ic gee 10+
Catbirdy2.. ase! S22 ses PBs. LIS ae | 3 | 2+ | 2— 3— 2— 2+
SONOS MATHOW at olka nd one mcm tact epee cab ae asa 9— i+ so11+ 6— 9+ 9+
Chipping sparrow ts Rk. 2 SA Ne Seo Lee EAR te oe ae T+ | 5+ 4a. 4— 6+ 5+
Mendowlark=.- =. SV es Sond side... cosheeee | 2+ 2— | it i= = 1+
HAP LISHISDATI OW,. «21s ciac > «eee = oie eis Calas op siecle widelate 7+ 6+ 5— 3— 44 5
A f Ot |
North Central States.
Species. pie
- Aver-
1916 1917 1918 1919 1920 age.
Per Ter Per Per Per Per
Relative abundance: cent. cent. cent. cent. cent. cent.
GON crater Me ccs siweenpns odetneeic Se enon cae aeecerae 6.1 6.4 6.7 5.9 5.9 6.2
aiming: asf KE SSSLLy FasL OST yeS ee 2.8 2.9 1.6 2.8 2.5 2.5
SONG SPAITOW - - .--- nan - nas grenade nnce--ncce-eabe 3.1 3.1 2.4 2.2 3.0 2.8
Chipping SPBLTOWs\.soe oe Le Teena cess teens 1.4 1.3 1.9 12 lags! 1.5
Meadowlarke.<- 225 sot soni vdse Peace: Soret 4.0 3.4 2.3 6.2 4.3 4.0
HMeMSh'SParrow..-2- se acee seca eee = sonia Swe 7.8 10.1 8.2 6.9 10.5 8.7
|
Average population per 100 acres: Pairs. | Pairs. | Pairs. | Pairs. | Pairs. | Pairs.
150) 0) has Sa eas NS SA Spe eg lo ee 8+ 8+ 10— 8+ 7+ 8+
Catbird.£ .2toa tas cs05-- cod) 2 beers 5. ease t- 3+ 2+ 4— 3+ 3+
DONE SPALL OW, «28s sanicls Cagis ait onions menigen smneeece 4+ 4 1 3+ 4— 3
Chippingisparrow J /20 JAS Ase. Seni Ge 2a bare 2— | 2— 3— 2— 2+ 2
Moad owlank. oe oo Ghs. Sactteade obin nacaecene eates 6+ | t+ 3+ 8+ 5+ 5
English sparrow..........-.0.+sssscecsscseceeeseee 104 Pg ga? gy | 3 |) are

In the States north of North Carolina and east of the Mississippi
River the robin is the most abundant species. Of some 200 reports
received from this part of the country during the past five years, only
6 do not record the robin; 4 of these deal with woodland and the
other 2 with the same tract of farm land in two successive years.
The densest robin population was found at Chevy Chase, Md., where
in 1916 31 pairs nested on 23 acres. This was in a residential dis-
trict in the suburbs of Washington, D. C., where the shade and
fruit trees about the houses furnished plenty of convenient nesting
sites and an abundant food supply. But on farm land, there were
found near Commack, N. Y., in 1916, 30 pairs nesting on 45 acres;
at Gettysburg, Pa., in the same year, 31 pairs on 40 acres; near
Geneva, N. Y., in 1918,48 pairs on 92 acres (nearly half of it in
orchard); and at Putnam, Conn., in 1920, 29 pairs on 60 acres.
Though in the North Central States the robin stands second in point
of abundance, when these records are combined with those from the
Northeastern States the robin becomes first for the whole region.

REPORT ON BIRD CENSUSES, 1916-1920. 23

The English sparrow occurs in such large numbers about towns
and cities, and has there so crowded out the native birds, that it has
come to be considered the most abundant species in the country.
Happily this is not the case. Essentially a city dweller and finding
its most convenient nesting sites in the vicinity of buildings, it has
nevertheless spread into the rural districts, and a few pairs are
found about the buildings of nearly every farm. Since the counts
in most cases have been made on the part of the farm surrounding
the buildings, it seems not improbable that the figures include all
the English sparrows on the farms where counts were made and
consequently furnish a rather high rating for the farming district
as a whole. This species seem to be relatively more numerous im
the North Central States, the returns giving it first place in that sec-
tion, while in the Northeastern States it stands third or fourth,
being exceeded there by the robin and song sparrow, and one year
by the chipping sparrow also. Returns for the Northeastern States
show that in 1916 there was 1 pair of English sparrows to 17 pairs of
native birds of all species, while in 1920 this proportion draped to 1
pair of English sparrows to 33 pairs of native birds. for this region
and period the record shows an average of two pairs of robins for
each pair of English sparrows.

The kingbird has Ant attracted the interest of the writer. The
bird censuses show that though so widely distributed and well known,
it is far from abundant. Evidently intolerance of his own kind has
been a factor in earning for it the name of tyrant. For the five years,
1916 to 1920, the counts of the birds breeding in the fields and orchards
show an average of only 1 pair of kingbirds to 50 acres of such land.

That large series of records are necessary before any conclusive
statement can be made regarding the relative abundance of the
different species, is shown by the following quotation from the pre-
liminary report of 1914:4

This preliminary census shows that the most abundant bird on the farms of the North-
eastern States [here meaning both Northeastern and North Central as considered in
the present report] is the robin; that the next is the English sparrow; and that following
these are the catbird, the brown thrasher, the house wren, the kingbird, and the blue-
bird in the order named.

Of the species then enumerated, the catbird is the only native
species besides the robin listed in the present report as among the
first six, and it falls well down the line.

DENSITY OF BIRD POPULATION.

No particular part of the country seems to have a monopoly on
density of bird population. The highest record for any considerable
area, 1916 to 1920, inclusive, concerns 40 acres of Golden Gate Park,
San Francisco, where 404 pairs of birds representing 36 species were
found breeding in 1916, something over 10 pairs of birds per acre.

Next to this m point of abundance of birds is a part of the village
of Chevy Chase, Md., where, in 1916, in five blocks containing about
23 acres, there were found nesting 210 pairs of native birds represent-
ing 39 species, besides the ubiquitous English sparrow, of which there
were 14 pairs. This is a residential district, where birds have been
encouraged and protected, and the lawns are planted to shrubbery,

4U.S. Dept. Agr. Bull. 187, p. 11.

24 BULLETIN 1165, U. S. DEPARTMENT OF AGRICULTURE.

with shade trees and several large fruit trees. Here the English
sparrow is outranked by four native species —the house wren, showing
17 pairs; the purple grackle, 20; the catbird, 21; and the robin, 31;
while the 14 pairs of wood thrushes just balance it. In one yard of
half an acre the owner found 20 nests belonging to 12 species of birds,
the most numerous being 4 of the catbird, which was the densest bird
ee reported during the period under discussion.

omparable with the Chevy Chase area is one of 25 acres near the
center of the village of Cloverdale, Ala., where 179 pairs of 11 species
were found breeding. ‘This again refutes the common belief that the
presence of human kind is inimical to a large avian population. The
Cloverdale report shows an average of 716 pairs on 100 acres; that at
Chevy Chase, 913 pairs. In the former case, however, the gregarious
English sparrow formed a much larger proportion of the bird life, the
110 pairs found being over 61 per cent of the total, while at Chevy
Chase, where the English sparrow has been somewhat “ discouraged,”
this species forms less than 7 per cent of the nesting population.

The high records for density of bird population above cited are, it
will be noted, all on suburban or park land. So far the highest record
for land actually farmed concerns 45 acres near Warren, R. I. In
1916 this land had 14 acres in orchard, 20 acres in swamp and brushy
pasture, about 1 acre in grove (otherwise no woods for several miles),
and the remaining 10 acres surrounding the house and barn, where
there are a few large trees, were planted to garden truck. On this
tract 163 pairs of birds were found to nest, a rate of 362 pairs to 100
acres. In 1920, 10 acres of orchard had been taken out and the land
planted to corn, but the tract still sheltered 154 pairs of birds, or 342

_ pairs to 100 acres.

This very dense population is explained by supplementary informa-
tion regarding 65 acres of adjacent territory. About 60 acres of the
surrounding land are used for market-gardening, and contain very few,
if any, nesting birds. It is, therefore, probable that the birds found
nesting on the 45 acres of the count were practically all those on 110
acres. This would make the averages 148 and 140 pairs to the hun-
dred acres, somewhat above the average for New England, but not
abnormally high.

BIRD LIFE OF MARSHLAND.

Two series of reports from widely separated localities, each cover-
ing the six years, 1914 to 1919, touch upon the problem of the bird
life about permanent marsh. Each area contained about 10 acres
of marshy land, but the two were so dissimilar in character that they
are hardly comparable.

Near Whiting, Ind., D. H. Boyd made counts on a 19-acre tract
of land divided as follows: 1 acre of small timber, scrub oak, wild
cherry, elm, and poplar; 8 acres of brush, narrow-leaved willow, and
sumac; 1 acre of cat-tails; and 9 acres of wild hay and rushes, partially
inundated in spring. Bird life here was exceedingly abundant,
nearly four and a half times that found to be the average for that part
of the country. In the six years the number of species nesting on this
tract ranged from 22 to 38, averaging 27, the total species for the
period being 55. The number of pairs has varied from 87 to 120,
with an average of 107. While the birds nesting on this tract have
been fairly constant both in the number of species and pairs, there

<

REPORT ON BIRD CENSUSES, 1916-1920. 25
has been a great variation in the kinds of birds found each year.
Of the 55 species that nested here im the six years, only 10 were
present every year, while 21 were present only one year each. Since
we have no other series with which to compare this, it is impossible to
tell whether this extreme variability is characteristic of marshland or

whether it is due to local conditions. (See Table 8.)

°
TaB_eE 8.—Birds nesting on 19 acres near Whiting, Ind., including 10 acres of marshland.
Species. | 1914 | 1915 | 1916 | 1917 1918 1919
rermeaeer. SOM eres eee ee 2 Sse Pe sasaie wes he fy i3 3. Lf 25: 7 10
— CTiy 7 27" lO Sa. - Se ee ee ee OSE el eee Ss poe eee eee 1
a eR 2 oS Set B08 Oy a ee BE Se : Ne Bie > 8S eh BSE ee Pee Ll Poe} 2

(0 So |. ee ee a ee eee Seer 1 } |. -2- ds eee
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emu rrr? ry. Dew ty Series. 2urk :. bere eed 2 led ey -Wos3} - et .--8 bins it. nee ee
JTS. trae eget 9 te 6. Eee ee eee ae a ee eee i ee ee + 2
pmremmnmemre. 22) S62) 7 2tee) Fish ifts. DR. RU ck Pl $23 1 tae Je |
TROT ta a Se ee ee ee 1 |) | os au-- = - |e degen lotas See ee ee
US DR TUSE TT Tie ae CE le ee ee 3 9 4 2 2 2
LE TPs oe SE Se ee ee ae eee es ee oe 2 SF) ee Lo Ae
0 PLE ee eee ee! ee i PE EE 1 1 1
EU TE RE Bh eS eg a A ee es eee BATS Soa af seo eae Pe oe oo eee ee
yo ahi 73 2a. _ oops Pereaegmees 3 503 VE j Ah PE ore) Cok a a) eee \ic aoe ches oe

ToT e LPT yor eh a ee es ee ee ee ee 1 | 1 ~| ae See eee eee eee

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ST SELLER a ee ee ee ie eee Pe 25-2) See ee eee
1 APES IOC Dilewa 22 Sanh See eee eee Be eee She oe ee
1 Sg ile 2, ai are ar ee ES ents 2 1 1 1 1 ESE Os
li SL OS ee ev ee Bie TE. A 323 ae eee
{Ruby-throated hummingbird ..........................----2. eee See See Se) 1
weet ee ee ee ee ee ee eee ane ; Sees Pee eee 2 1
SOT Y eT Des Se ee ee eee el ee See 1 1 1 1 eee ©
ol i a a ee eres a ee Bee ee
2 EE RE ee a eee Se eee eee eee ] 3 2 5 3
olf a y oy 2 i a ee eee eee nnn Sens | 1 -beepeencefeccsasechl lL Ae ee

OU. 2 ee eh Serre eee ae i) eeeSees Pees ee 1 |} 1
SS oo a ee eee 5 | 7 6 5 7 6
. STD co Dees SSE ae eee eee ere 3 | 4 + 7 | 3] 2
LPTs evil. 21 ee ee ee eee 25. | 17 21 25 30 25
7 LU EET DSU Pe RE ee a ee ae eee 4] 3 i 3 3 Q

mremremernekigee: $2. ob a etecie ef ysis s5ehoRe.5 1 7 pag gS
“PS LS ES ee ee ee eee eer ee 2} 5 2 S522) 2t 1
eo. 3 aes ee ee eee ee eee a ee sts 2 fe 2
Ey 2 0 ae 2 Se ee Se ot eee =e 1) EE Perea ey eee by tae oay 21° es
TST ie Se a eee eee eee 3 | 10 11 9 4 8
2 LO 2 a Re, ee ee eee ee Oh Feces te wttscdcfsescs ccf Oe eee
0 ee eee een eee eas Bee eee hess cocees ee eee
2D SS DE Bio ee See eee eee es ye Pees ere eed pS
2 LG ae ee eee ee eS oe 10 ec ecee ge ceesee ge ceeeee ge senses PY ile)
TEPC SG LO Bg eee Ae, Seer 1! 2 3.) 3 34 3
) So) Ae = Ao 8 Se ee ee EE Se TS PPP ern ye pebioncas
pinck.said Wititp Warbler. .- <<<. <2 222222 -.s5s20-<2 sce}: sees sis Bcc sccucehs::: Spe SMS nO
een © Je kB Ak. eee 10 | 14 14 11 16 | 18
SII, ot Peet. 8 bo. loci bessfealecidt | oe eS Reet ees erty ees A
TU STs) ee ee ee 1 2 2 2] 3
SL ee eB ef See Se ee Oe ene Bent catuthessceocs he eee
oo SE ee ee eee eee ee 4 | 5 7 5 4 5
ee ee en en 1 | 3 2 3 2 2
House wren........ TS.) So Es ee eee ween yeas 3 5 1 1 2
SSIPTO RS Sra io gb? 2 rc See eee 5 eee eee 1-1 222522.0R SS ate
vg Bae eee eee eee ee 1 12 7 8 16
Par SSP Ne eee ee eee eee LS ae ay ec ery ane
ow AO Sey ee pia eee eee eee eee 1 1 Bho) a See
(DUES See ae eng ee Se ee Ge oe oe eee eee 2 1 1 je ah Net
Total number. OF species... - 2.5... 2-22... S255 22. | 38 27 27 24 24
Total number of nesting pairs................... 87 | 115 112 99 109 | 120

* Present every year. ¢~ Present only one year.

The second series of counts was made by C. J. Pennock on 82 acres
about the village of St. Marks, Fla., situated on the St. Marks River,
8 miles from the Gulf of Mexico. A roadway and arailroad track about
bisect the area, and along these are 25 buildings, two-thirds of which

’ >
are dwellings. A few buildings are on the river bank. Only 2 acres
OR? ne

c

Ie mn

26 BULLETIN 1165, U. S. DEPARTMENT OF AGRICULTURE.

are cultivated, in gardens and a small cornfield. The tract contains
three small rain-water ponds without outlets, 6 acres of tidal marsh,
and 6 to 8 acres of coarse grass inclined to swamp. About a third of
the entire area is covered with timber, mostly pine, with a few
cypresses and live oaks near the river. The remainder is open grass-
land having some scrub palmetto, and most of it used for grazing.
At St. Marks the average number of species was 36, with a total of
44, of which 29 were present every year, and there were only 4 species
that were found only one year each. (See Table 9.)

A considerable contrast is noticeable between this area and that
near Whiting, Ind., in regard to the stability of the species nesting,
as will be seen in the accompanying Tables 8 and 9. At Whiting,
Ind., the species present every year were 18 per cent of the entire
number found and 38 per cent were present only a single year.
At St. Marks, Fla., on the other hand, 64 per cent of the species
were present every vear, while those found only once represented
only 9 per cent.

TABLE 9.—Birds nesting on 82 acres near St. Marks, Fla., including from 12 to 14 acres
of marshland.

! ] ‘ '
Species. | 1914 | 1915 | 1916 | 1917 | 1918 | 1919
= re 2 2 - } —
|

ANS WANE. Ft es Os RSS BEES. ad eee ae felt Sone dnl eee inaeebee 2
ablorida clapper Tall «<< 2. .celeSmwnoess Renae ite ds | 1 1 2 1
POLI RA MTIMIO'S: 2. 2.5 Eo. cn cadecsaersy cep emeicewes |ereeeeccleneeecee Pattee 2
+0 eee Be ts, Sem ee bak ees ae

PS Vellow-piled CHCKOGs>~ b.-0- 3c sc gasccottpsosseneeoes
petoride. Seroech Ow! =. 2-6... nc Seen cee amens saga be en laeaeney el scene leet meee

Southern downy woodpecker...................---..- fit Yes:
SieCG-DelNed WOOGPCCKELDS. ot :.. - (Sic. =-- reo ences 3

LDA 0 9 pre Eerie Soe dee. Se See Gees SE oe See Te ee OF eae 4A see AE
PEC RO WEL S-WIGOW - «2 6 ics ico acice meetin od- fas abotns oh 2
=Hupy-throated hummingbird - = 2522... 4fee cow eke | 1
BRAN SUK 22 5s Ment « Sse ciod - outs fe facia seen aire ee 3
AO Pestedur VCALCOGr. 02. LE au. eee de eink Stab cape een 3

WVOODEAHOWEO =. och -2s2 Spe LAE es ace. Len eeeees 1
PACIOTUOA DIO JBN —« «5. mo Sse one ald an Sante ew cet hecs | 6

RL GEIA CLOW < os a os Jaro Bien ooo Beene Seat e tee abner 1
ST MMUAST OG WIN Fae oF ot ees nol. Se Sa eee es + ecco -
MeGHbhoEn MeCAadOWwlark.....-..2scsa0cos can boseackeos ere ee ee ee
BAT CHAE BMOls 28) fui teh cic. aap Rie aces to bae mene enn |
Elon oTaekios oo. 2.02 flo bl ere ee ee |

osi-tarled, STrackle. 2... Jews skertne ee ened aaeele ante
BV AIGC-CY¥Od TOWNMGE =. 2b oe co hdo nn csdibcceseahes
Rrmaiitwteasdinale: 05.62 = lnc Ike odvcn pent es |
SRTMEINOMANACOD Ss =-.20 oc) Bc Soe Sow ones oo See etic noe
PT OO AMAT GIN. 2). oc Sana > ae Pace Sed Sompet po ctse sch ehis
eno n-winted: SWAllOW:. .-8< cc lode oe aoe oobe n= -keuece | ee ee eee ee
RBECCLNGAG. SHITKE cst to eee ae oa bese et 3 te te | 2
Meltaw-Laroated yireo 8.2 2.6 2. fee come dase ter nceces | 1
PTIEEO OUR VITCO!. 82-322 © oot. Stee. sae aces oor eicass | 2
Earls warbler. <.9'.25. 2 eee asc cctesecees ma ee nee hoe ee
SYellow-throdted warbler... =~... deneencdeccase- ones | 1
“J ETUILE 025g 0) gee ee oe TEE CES ES Oe Se Oe j 3
Pi Oridanvenlow LONORE a oho 28 oobi o eet Bn ae tien 1
CLG UD CLRECT Oy STs CIR pt re ete, oh AE Se 6
SRrOWI onTaSuer- re... 2.5 ele ase. See See | 3
2
1
2
-

_

ry
_
—

ero wn-neaded nuthatel.. - 2.58 3 eee he Se
SETECHTTETTIONSC: = 5-23 22 Sort ore eee ea oc
-Caroknachickadee: - 24: s2c2s sett cbse ek eee ssc
EBUIC- PLAY CNALCALCHED .oc25~524-2 aoeisacte ae ae oe

PGE IR GES en oe wa ocd Somnd cabal nese eee omc ne dlnus Soeee ie oe

Pesserisrivass DUTTON... See. ROR Soe ee ct as |

WoEWH EE CKONANEL -

10 1

| |

Totaliaamber of Species... 50. Lets Bll FIA...
Total number of nesting pairs..............----

cow

He ee
i
he
oor
ry
ed
“10
w
~

* Present every year. + Present only one year.

REPORT ON BIRD CENSUSES, 1916-1920. 27

Perhaps the best idea we can get of the bird life of marshland is
given by a count made in 1916 on a 56-acre tract near Hinsdale, Ill,
containing 15 acres of oats, 10 of pasture, and 31 acres of marsh, about
20 acres being under water all the year. There were a few live wil-
lows about the edge and many dead trees in the marsh, and about
half the marsh was grown up to flag, cat-tails, and reeds. The 15
species of birds found nesting there were represented by 140 pairs
at the rate of 250 pairs per 100 acres, more than double the average
for farm land. This bears out the belief that such places are very
rich in bird life. The birds found were:

Pied-billed grebe, 1 pair; black tern, 4; blue-winged teal, 1: least bittern, 2; king
rail, 1; Virginia rail, 9: American coot, 6; killdeer, 1: mourning dove, 3: bobolink,
2; red-winged blackbird, 68; meadowlark, 7; field sparrow, 11; swamp sparrow, 2;
long-billed marsh wren, 22.

BIRD LIFE OF THE WOODLAND.

The forested regions of the country have a much smaller bird popu-
lation than the open land. The deep woods are places of compara-
tive silence; there seem to be no birds there. Small patches of
woodland on the contrary, such as the woodlots of farms, are usually
very rich in bird life, especially if the underbrush is not kept cleared.
Particularly is this true when the surrounding fields are so much
under cultivation as to provide few good nesting sites but an abun-
dance of food. Very few reports of the birds breeding in heavily
timbered areas have been received, but those at hand indicate that
for each 100 acres of forest there are from 50 to 100 pairs, or an actual
average from the reports of about 68 pairs of nesting birds. For
the woodlots the bird population is nearly three times this, the re-
ports showing an average of about 182 pairs of birds per 100 acres.
This latter accords with the returns for 1914 and 1915, which gave
an average of 187 pairs of birds per 100 acres of such land. The
present figures for the population of the heavy forest, however, are
more than those previously obtained. This is probably accounted
for by the fact that some of the counts used in this average were
made near the edge of the forest, where birds are more abundant
than in the deeper parts.

Three reports have been received which deal with the forests of
the Rocky Mountain region. On the east shore of Flathead Lake,
Mont., at an altitude of about 3,000 feet, 45 acres of forest contained
only 21 pairs of birds in 1916. In the same year 60 pairs were found
breeding on a tract of 120 acres near Falcon, Idaho, at an altitude
ranging from 4,500 to 5,000 feet. These two areas show approxi-
mately the same average of one pair to 2 acres. The same average
holds in the southern part of this region, according to the count
made in 1920 in the Santa Fe National Forest, previously mentioned.
It seems safe to assume, therefore, that 50 to 55 pairs of birds to
100 acres would be the average for the forests of this region and
probably also for similar land in the East.

Only one report is on file for a continuous forested area in the
East, that made in 1920 by Charles L. Whittle on 562 acres near
Peterboro, N. H. This land, situated at an altitude varying from
800 to 1,200 feet, is a part of continuous second-growth timber, the
trees being from 20 to 40 years old, predominantly white pine, with

a ee ee rr ie, fa ee fe ee? ee ae ee ee ee ee ee. es ee ee eS —eeeee—e—eeeeeeeeeeeeeeee eee eee ee ee aaa

28 BULLETIN 1165, U. S. DEPARTMENT OF AGRICULTURE.

some areas largely birch. In the northwest corner is a small swamp
covered with alders. On these 562 acres there were found 502 pairs
of nesting birds, representing 52 species, or at the rate of 89 pairs
per 100 acres. This is 78 per cent greater than the bird population
found in the Rocky Mountain forests, but is probably explained by
the difference in the kind of land surveyed rather than in the number
of birds per acre in the eastern and western forests. In this case
part of the woods was adjacent to open land, so that birds would
naturally have been more abundant than in the deeper forest.

This wooded area surrounds a tract of 78 acres of cleared land,
which was also surveyed. The latter tract contained 48 acres in
grass and other farm crops, with about 50 old apple trees scattered
over it, and 1 full acre of dwarf orchard. In one corner was a swamp
of about one-eighth of an acre, drained by a wet-weather stream.
Efforts had been made to attract birds by the placing of bird baths,
a 16-compartment martin house, and a dozen bird boxes. On this
land there were 162 pairs of birds representing 23 species, a rate of
about 208 pairs per 100 acres.

Regarding these two areas Mr. Whittle says:

It appeared to us that this sharply defined relationship of forested land, surrounding
closely and nearly solidly an unforested tract, afforded an excellent opportunity to
compare the nesting bird life of each area, and, while the area selected 1s somewhat
ambitious as to size, I can assure you that it has been combed by systematically spaced
swaths (cruised east and west), and the lists submitted perhaps contain no more errors
than appertain to the nature of the work. * * *

The most abundant family was warblers, of which there were 11 genera and 262
[pairs of] birds, or 39.45+ per cent of the total number of all birds found. To this
family also must be credited the largest number of any single species; 66 oven-birds
were found, constituting only a fraction under 10 per cent of the total birds. The
robin was next in abundance, comprising 9+ per cent of the total.

The robins’ nests in the larger area were confined to the immediate inner border

next the open fields. None nested in the deep shade of the thick pine forest, especially
where the trees are large.

SCARCITY OF BIRDS IN 1918.

A decrease in the number of breeding birds per acre in 1918 was
noted in many cases when tabulating the results of the bird counts
for the five years 1916-1920, and a close study was made of the sub-
ject in order to ascertain whether this decrease was real or only
apparent, local or general, and, if possible, its cause. For the part
of the country lying east of the one hundredth meridian there are on
file 24 series of reports covering the same tracts of land for at least
the three years 1916-1918. These reports cover a total of 1,478
acres and represent areas picked at random in 18 States, from Maine
to Florida and from Minnesota to Texas, and may be considered to
reflect fairly well the conditions in the eastern United States.

Examination of these reports reveals that in 1918 73 species show
a decrease on two or more reports and 28 more on one report each.
Ten of the species show a decrease on four reports and 22 on five
or more, the highest being the catbird on 11 reports and the
phoebe and song sparrow on 9. The following list will give some
idea of the species affected: Mourning dove, 2 cuckoos, 7 species
of woodpeckers, nighthawk, chimney swift, 2 species of humming-
birds, 8 species of flycatchers, meadowlark, 2 orioles, 19 species of
sparrows, 2 tanagers, 3 species of swallows, 6 species of vireos, 13

REPORT ON BIRD CENSUSES, 1916-1920. 29

species of warblers, mockingbird, catbird, brown thrasher, 4 species
of wrens, and 5 species of thrushes. It will be noted that a large
number of these birds are insectivorous and that comparatively
few of them winter within the United States.

The numerical decreases of some species on the above-mentioned
reports may be of interest. The figures given in Table 10 seem
small, but when it is considered that the total acreage to which they
apply is only an infinitesimal part of the whole area presented, they
become significant.

TABLE 10.—S pecies of birds that in 1918 showed a marked decrease in numbers.

Number Number ;

Species. of Decrease Species. | f Decrease

| reports. | 1 Pairs. reports. | 1 Palts.
MoNIMIne Gove... -£.......-i-.- 6 | TC Scarlet tanacers.4- 3.2. seo. 5 10
NE es os ees am. == - | 8 11 || Red-eyed -vireo.. 2: 22522... 0. 6. 8 11
Ee ee eee ree 9 138 | Maryland yellowthroat........ 6 8
WyiOGd NOWEl-...--s---- ee... ae PEN BRODIT. .25- eon se's- cogs ces ccc 11 14
Weadbwilark i it...i. ke. 25. 7 | 11, || Brown thrasher-- 2... f..-2.-: 6 8
Baltimore oriole............... | 6 (al EROUSE WEM =. ce =. aces. acta: = 7 9
Sone snarrowita-<2-5~-22e<--: 9 | SUN 80) ob One see ee Oe ee 8 18

The greatest decrease in the total number of breeding pairs on a
given area was 462 per cent on 40 acres at Florence, Ala., and two
other tracts showed decreases of over 40 per cent each.

Examination of the reports shows that of the total land surveyed
only 6 acres more were plowed than in the preceding year, thus
eliminating the possibility that more intensive cultivation had caused
the birds to nest elsewhere. Neither could severe weather conditions
during the previous winter have affected those species that winter
south of the United States.

EK. H. Forbush, State ornithologist of Massachusetts, made an ex-
tensive investigation in 1917 of the effect on insectivorous birds of
the cold and rainy weather of May and June of that year. He found
that during that time thousands of birds perished from lack of food,
due to the weather conditions. Concerning this destruction of bird
life by the elements, he says in part:

* * * The weather report asserts that the low temperature and lack of sunshine
retarded vegetation, so that the season at the close of May was from three to four weeks
later than normal,

* * * Tt was not until the middle of June that the wild flowers appeared as they
ordinarily do in the latter part of May. There was asimilar delay in the appearance
ofinsects. Eggs ofinsects failed to hatch at their usual time, but apparently the cold
weather did not destroy them. With the exception of tent caterpillars and a few
others, insects appeared in their full, normal numbers later in the season. A few
birds appeared earlier than normally, but the main flight of insect-eating birds came a
week or ten days later than usual. Even then the birds came too soon, for their insect
food was not ready for them. Many of the early swallows and martins apparently suc-
cumbed to the cold storms which came after the birds arrived. Several observers
report finding dead martins and swallows in nesting boxes. * * *

* In going over the reports from various correspondents the first fact.almost
universally observed was that of an unusual flight of birds, particularly insect-eating
species, such as warblers. Only a very few observers had not noticed this. The next
fact noted was that the birds were much less shy than usual, and that they were seen
more about houses, in villages and closer to the ground than in ordinary seasons.
The warblers were so weak and so preoccupied in seeking food that many of them
could almost be taken by hand, and as they grew weaker some were so caught.

' Forbush, E. H., Tenth Annual Report of the State Ornithologist, pp. 14-22, Boston, Mass., 1917.

30 BULLETIN 1165, U. S. DEPARTMENT OF AGRICULTURE.

* * * This destruction of insect-eating birds over a large part of the State is a
serious matter in itself, but evidently similar conditions were maintained over a much
larger area through northern New England to New Brunswick, at least as far south
as Pennsylvania and as far west as Michigan. A few reports from other parts of the
country indicate that the decimation of birds in many other regions was quite as
serious as in Massachusetts.

* * * No one can tell how far the destruction of bird life extended, but a glance
at the weather map seems to indicate that conditions more or less similar to those
in New England during May existed nearly all the way across the continent.

* * * Nothing has been heard of any bird catastrophe in the South, and little
is known about the effect of the backward spring in Canada, where it may have been
very destructive to bird life. The great catastrophe, then, seems to have been con-
fined mainly to a large part of a tract about 1,000 miles in width, extending from
Pennsylvania and Michigan north into Canada; but just how far, no one knows.

Because of the stormy weather and the backward season, com-
paratively few young birds were raised that year. Cold prevented
the hatching of many eggs, and lack of foliage left the eggs and
young exposed not only to storms but to their natural enemies.
Jays and crows, unable to secure insects, turned to the eggs and
young of the smaller birds for food. Heavy rains caused floods, in
places doubtless drowning out birds that nest in low bushes or on
the ground.

It is the generally accepted belief that under normal conditions
the young birds of one season about equal the number killed from
all causes before the young of the next season are on the wing. It
becomes evident, therefore, that following such an unfavorable
breeding season as that of 1917, the birds affected would return to
their breeding grounds the next year in greatly depleted numbers.

The birds that survived the migrations to and from their winter
home again encountered unfavorable conditions when they reached
the United States in the spring of 1918. Migration tables indicate
that these birds should have arrived in the United States from the
middle of March to the latter part of April. According to weather
reports for 1918, February and March throughout the Gulf States
were warm and dry, but April, except the first few days, was unusually
cold and rainy, with excessive precipitation in some places. On the
12th a killing frost extended as far south as northern Florida. Such
conditions doubtless further decimated the numbers of migrant birds.

In the case of those species that winter in the United States, the
unusually deep snows of the previous winter might well be considered
the principal cause of their scarcity during that summer. It is
known that in the vicinity of Washington, D. C., Carolina wrens
became very scarce after a heavy snowfall early in February, and
there seems good evidence that they perished rather than migrated,
since they did not return with the warm weather but continued to
be scarce for at least two years. After the storm, they were seen
searching in unusual places, indicating that food was difficult to find.
The same thing has been noted elsewhere in different years with
regard to this and other species.

That this scarcity of birds in 1918 extended into Canada is
indicated by a series of reports from Manitoba. Two tracts with
a total of 102 acres, on which counts have been made since 1914,
showed in 1918 a decrease in 13 species elsewhere noted as scarcer
that year; and a total decrease was noted of 20 pairs, or slightly
over 13 per cent.

|
.
|

REPORT ON BIRD CENSUSES, 1916-1920. 3]

Wherever the data over a given tract continue for 1919 and 1920,
they indicate a gradual return to the normal numbers of breeding
birds. In some cases, in 1920, the total number of birds nesting
was greater than in any previous year recorded.

One of the largest continuous areas on which a census has been
taken is 210 acres at Rhinebeck, N. Y., a part of Grasmere Farms,
and M. S. Crosby explains that in making the count he divides the
tract into five sections, going over each several times during the
breeding season. This tract contains 92 acres of woods, creek, and
swampy land, 40 acres of orchard, 58 acres plowed for crops, 5 acres
of pasture, and the remaining 15 acres in drives, lawns, gardens, and
buildings. All birds except starlings and English sparrows are
strictly protected and the latter are kept down to 15 to 20 pairs.
For the years 1915-1917 the bird life here was fairly constant and
averaged 369 pairs and 55 species, a rate of 176 pairs per 100 acres.
No count could be made in 1918 or 1919, and when the count in 1920
showed only 254 pairs of 47 species nesting within the area,
Mr. Crosby expressed himself as much puzzled and totally unable
to account for the great decrease and even total disappearance of
certain species formerly common. This decrease now seems to be
satisfactorily explained and it is a matter of regret that the minimum
figures are not available.

Evidently the loss in bird life here in 1918 was very great or else
something in local conditions retarded the recovery, since in 1920,
the second season after, the number of birds breeding was still
30 per cent below that of 1917. It is possible that this indicates
very nearly the minimum, for areas on which there are continuous
reports show little or no increase in 1919, though in most places
the increase had become considerable by 1920.

BIRDS RESPOND TO PROTECTION.

Birds are too few on the farms, especially about the parts more
intensively cultivated, and should be encouraged in every way.*
Protection alone will help a good deal, as shown by the increase in
bird life at Viresco, Va., already noted; but at the same time shelter
and nesting sites must be provided, or, at least, not destroyed.
Clearing the brush from woods and along fences and roadsides
destroys the nest sites of many birds, driving them away from
fields where their assistance is needed. Efforts toward attracting
birds should not be limited to the area immediately surrounding
the house, but. should be extended to the part of the farm that is
under cultivation. Most nesting birds subsist largely on insects,
and young birds are fed almost exclusively on them.

The response of birds to protection and friendly care is shown by a
report from near Pontiac, Mich. Here a tract of 150 acres has been
posted for several years and the birds thereon carefully protected;
dogs have not been allowed to run wild, all vermin have been shot
on sight, and English sparrows have been kept down by shooting
and trapping. Over fifty bird houses have been erected, including

6 Farmers’ bulletins of the United States Department of Agriculture on methods of attracting birds are
as follows: No. 609, Bird Houses and How to Build Them; No. 621, How to Attract Birds in Northeastern
United States; No. 760, How to Attract Birds in Northwestern United States; No. 844, How to Attract
Birds in the Middle Atlantic States; No. 912, How to Attract Birds in the East Central States; No. 1239,
Community Bird Refuges.

32 BULLETIN 1165, U. S. DEPARTMENT OF AGRICULTURE.

a 22-room martin house, and regular feeding stations are maintained
during about eight months of the year.

A bird census taken on 60 acres of this land in 1920 shows that
the birds have not been slow to recognize the advantages of this
area as a nesting place, but no data are available for comparison to
show what changes have taken place since the land has been pro-
tected. This section contains the house with flower garden and
lawn, about 20 acres of woods including hardwoods and tamarack, 34
acres of plowed land, and the remainder in grass, with scattered
shrubs, mostly juniper. The land is hilly, the higher and more
heavily wooded part to the north and west, and sloping to the south,
where a small lake extends into the tract for about 2 acres. There
are three small ponds and a creek flowing into the lake, the shores
of which are marshy, the trees in some places coming nearly to
the water.

Here the birds find food, water, plenty of shelter, and protection
from their enemies, natural as well as human, and they have responded
by nesting about three times as closely as the normal average. The
birds found breeding were as follows:

Woodcock, 1; mourning dove, 6; red-tailed hawk, 1; black-billed cuckoo, 3; red-
headed woodpecker, 4; flicker, 2; whippoorwill, 2; ruby-throated hummingbird, 1;
kingbird, 1; crested flycatcher, 2; phoebe, 2; wood pewee, 6; blue jay, 3; crow, 3;
cowbird, 10; red-winged blackbird, 5; Baltimore oriole, 4; goldfinch, 7; chipping
sparrow, 7; field sparrow, 15; song sparrow, 11; towhee, 8; indigo bunting, 5; scarlet
tanager, 2; purple martin, 10; bank swallow, 2; cedar waxwing, 2; red-eyed vireo, 5;
yellow-throated vireo, 1; yellow warbler, 15; cerulean warbler, 1; ovenbird, 3; Mary-
land yellowthroat, 4; catbird, 12; brown thrasher, 1; house wren, 12; white-breasted
nuthatch, 1; blue-gray gnatcatcher, 4; wood thrush, 2; robin, 10; bluebird, 7; English
pheasant, 1; English sparrow, 10; a total of 214 pairs of 43 species.

At Silver Spring, Md., in 1917, the birds gave evidence of their
appreciation of efforts in their behalf. ‘The owner of a 6-acre tract
has left the place wild for the sake of the birds. About half of this
land is hilly meadow, considerably overgrown with bushes and
young locust, and the rest is divided about equally between tangled
woodland, garden, and grove around the house. Additional attrac-
tions have been supplied in the form of feeding stand, bird bath,
and several nest boxes. The birds that responded to this care in
1917 were:

Bobwhite, 1; red-headed woodpecker, 1; whippoorwill, 1; kingbird, 1; phoebe, 1;
wood pewee, 1; starling, 1 (the second record of the breeding of this species in the
vicinity of Washington); orchard oriole, 1; field sparrow, 1; song sparrow, 2; chewink,
2; cardinal, 1; indigo bunting, 2; red-eyed vireo, 2; Maryland yellowthroat, 2;
yellow-breasted chat, 1; redstart, 1; catbird, 4; brown thrasher, 1; house wren, 7;
robin, 2; bluebird, 2; a total of 38 pairs of 22 species.

Several instances of the abundance of birds on protected areas
have already been mentioned. Others may be cited. An average
of four years’ records at Savannah, Ga., shows 30 pairs of 22 species
nesting on 12 acres, about half of which is woodland. At Collins,
N. Y., a tract of 28 acres, about equally divided between woods and
ppen land, is protected, but no extra attractions are furnished for
the birds. Nevertheless, seven years’ counts show the average of
33 species and 72 nesting pairs of native birds. At Ewing, Ill., 5
acres, of which 2 were orchard and 1 garden, for four years have
averaged a population of 22 pairs of 13 species of native birds besides
4 pairs of English sparrows. At Putnam, Conn., on 60 acres, of

}

REPORT ON BIRD CENSUSES, 1916-1920, 33

which 1} are in orchard, 4 to 5 in crops, and none in woods, there
was an average population for four years of 32 species and 121 pairs
of native birds and 2 pairs of English sparrows.

SUMMARY.

Results of bird censuses for the five years 1916 to 1920, inclusive,
show a very close agreement with those obtained in 1914 and 1915
for the section of the country lying north of Maryland and the Ohio
River and east of the Great Plains—a little more than one pair of
birds to the acre as the average for farm land. For the land imme-
diately surrounding the buildings and including the lawns and orchard,
on the average about 130 pairs of birds are found to nest on 100 acres;
the estimated bird population of the entire farm is about 112 pairs
to 100 acres. :

The counts made in the southeastern section of the country have
been on tracts so scattered and of so small an acreage that no con-
clusions concerning the average bird population are yet possible.
The same is true of counts on the Plains, where, except for a few
species, birds are largely confined to river bottoms and planted
groves. In the Rocky Mountain region and westward, the country
is even more diversified, and the added problem of altitude makes
general averages practically impossible, even with many times the
data now at hand. |

The robin is the most abundant species in the States north of
North Carolina and east of the Mississippi, and the English sparrow
is second. For the farm land in this section, as represented by the
counts, there are approximately 9 pairs of robins and 8 pairs of
English sparrows to 100 acres.

No general statement of the average bird population of marsh
areas is at present possible. The marshes are the home of several
“oye ace species, and the a a per acre is, therefore,
usually much greater than on farm land.

In small patches of woodland, especially when they are surrounded
by cultivated fields, birds nest very abundantly, but in the deeper
woods they are scarce. For the former, the average bird population
is 182 pairs to 100 acres; but the estimate given of 68 pairs to 100
acres of the latter is probably rather high. Several counts made in
the forests of the Rocky Mountain region show about one pair of
birds breeding on two acres, and it is probable that the same propor-
tion holds in similar regions in the Eastern States.

The counts of 1918 showed birds to be much less abundant than in
other years covered. Unfavorable weather conditions during May
and June of the year preceding took heavy toll of the insectivorous
birds throughout the States east of the one hundredth meridian, and
unusual storms in the Southern States during the winter and spring
which foliowed proved hard on birds wintering there. By 1920 much
of the loss had been regained.

Birds respond to protection, and on areas where they are protected
they nest much more abundantly than on surrounding territory.

34 BULLETIN 1165, U. S. DEPARTMENT OF AGRICULTURE.
FUTURE WORK,

The bird census work must be carried on through many years and

on a much larger scale if exact data are to be accumulated on which |

to base definite comparisons for determining what changes are taking

lace in the bird life of the country and whether these changes are
fea or general. ‘The data now at hand indicate that on a given area
where birds are protected the number breeding will gradually increase
from year to year; but how long this will continue and what will occur
when the maximum density is reached can not yet be determined.
Previous to the destructive season of 1917, the results of which were
so apparent in the censuses of 1918, there had been a gradual increase
in the number of birds per acre on many tracts in the eastern United
States, and following this setback birds are found to be again on the
increase.

Long series of exact records, such as this work will provide, will
indicate whether the birds in the country as a whole or in certain
localities are increasing or decreasing; or whether following periods
of increase, setbacks such as the unfavorable season of 1917 tend to
keep the average over a period of years approximately the same.
From the work thus far done, it seems that over a long period changes
may be expected in the distribution and relative abundance of certain
species, rather than in the total number of birds in the country. On
some tracts, little change in the number of birds is apparent from year
to year, while on others an increase is shown, and on still others a de-
crease. Are such changes due to local conditions or are they part
of definite changes that are taking place in the bird life of the country ?

With bird censuses continued year after year, a large amount of
increasingly valuable data will be accumulated, from which much
can be learned regarding the bird life of the country and the changes
that take place. Each year’s records add to the value and useful-
ness of those already on file. Many problems are presented by the
material now in hand and new nites are brought out by each
year’s work, for the solution of which we must look to the future.

€

|
:

PUBLICATIONS OF THE U. S. DEPARTMENT OF AGRICULTURE RELAT-
ING TO THE DISTRIBUTION, MIGRATION, AND ATTRACTION OF WILD
BIRDS.

FOR FREE DISTRIBUTION BY THE DEPARTMENT.

Bird Migration. (Department Bulletin 185.)

Eleven Important Wild-Duck Foods. (Department Bulletin 205.)

Propagation of Wild-Duck Foods. (Department Bulletin 465.)

Migration Records from Wild Ducks and Other Birds Banded in the Salt Lake Valley,
Utah. (Department Bulletin 1145.)

Bird Houses and How to Build Them. (Farmers’ Bulletin 609.)

How to Attract Birds in Northeastern United States. (Farmers’ Bulletin 621.)

How to Attract Birds in Northwestern United States. (Farmers’ Builetin 760.)

How to Attract Birds in the Middle Atlantic States. (Farmers’ Bulletin 844.)

How to Attract Birds in the East Central States. (Pennsylvania to 100th meridian.)
(Farmers’ Bulletin 912.)

Community Bird Refuges. (Farmers’ Bulletin 1239.)

Game Laws. (Annual publication, that for 1922, Farmers’ Bulletin 1288.)

The Great Plains Waterfowl Breeding Grounds and Their Protection. (Separate 723
Yearbook 1917.)

Federal Protection of Migratory Birds. (Separate 785, Yearbook 1918.)

Conserving Our Wild Animals and Birds. (Separate 836, Yearbook 1920.)

Instructions for Bird Banding. (Department Circular 170. )

Migratory Bird Treaty, Act, and Regulations. (Biological Survey Service and
Regulatory Announcement No. 55.)

FOR SALE BY THE SUPERINTENDENT OF Pe ee GOVERNMENT PRINTING
OFFICE, WASHINGTON, D. C.

Distribation and Migration of North American Shorebirds. (Biological Survey
Bulletin No. 35.) Price, 15 cents.
Fifty Common Birds of Farm and Garden. (Farmers’ Bulletin 513, with color plates.
Price, 15 cents.)
35

an oe an es

a a a EY
‘ i

ORGANIZATION OF THE |
UNITED STATES DEPARTMENT OF AGRICULTURE. |
|

|

|

mecreiary Of AQTiCUuUre. 22a o. Sos ses ise kes Henry C. WALLACE. |
SRE SCT EIOLY Jan as ccls ea x Jes oe se we ae C. W. Pucstey. |
Pearceipr OF Scveniyfio, WOK «6 2! wien wmrd's hes < E. D. Batt.
Director of Regulatory Work ......-.........-- —_—__—_.. |
PREMERCE URED. 2 op dll dee vine vin oem oye CHARLES F. Marvin, Chief.
Bureau of Agricultural Economics......-.-.--- Henry C. Taytor, Chief. 4
Bureau of Animal Indusiry ....---.-+-.--+--- Joun R. Mouter, Chief.

Penrenito; slant Wedustry . - 2.2 2< ~<mcmgieenns Witi1am A. Taytor, Chief.

PEEPS NELUICO.. 3b ti hs a ee aici we W. B. Greewey, Chief.

neat Of CROMISIFYs... 2/5 a's one See eRe WALTER G. CAMPBELL, Acting Chief.
PAPA OS USOUS 150. 2S. x tithe oie Deen 5 eee 2 Mitton Wuitney, Chief.

Bureau of Entomology..........---4-.-02204-- L. O. Howarp, Chief.

Bureau of Biological Surdey. 2 iot0 Jes E. W. Neuson, Chief.

Peer eat. Of.-F UDC: ROGGE «oo ~ = aim etal 5 3 ola oie Tuomas H. MacDonatp, Chief.

Fizxed- Nitrogen Research Laboratory .......---- F. G. Corrrety, Director.

Division of Accounts and Disbursements........ A. ZAPPONE, Chief.

Pursen of Publethons 2 yc. Se ae. Epwin C. Powe, Acting Chief.

I cas ects t phe Sy Sores raced ele cht: ee CLARIBEL R. Barnett, Librarian.
mratcatielations Service... 2.5 2. os gow Ales A. C. True, Director.

Federal Horticultural Board.................-. C. L. Marnatt, Chairman.

Insecticide and Fungicide Board................ J. K. Haywoop, Chairman.

Packers and Stockyards Administration........ CHESTER MoRRILL,

Grain Future-Trading Act Administration . . . Assistant to the Secretary.

Oiice of the Solveitorsini50' de Med A PIBa ee. ah R. W. Wiittams, Solicitor.

This bulletin is a contribution from

Bureau of Biological Survey .........-.------ E. W. Netson, Biologist and Chief.
Division of Biological Investigations...... E. A. GOLDMAN, Assistant in Charge

36

ADDITIONAL COPIES
OF THIS PUBLICATION MAY BE PROCURED FROM
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GOVERNMENT PRINTING OFFICE
WASHINGTON, D. C.
AT
5 CENTS PER COPY

PURCHASER AGREES NOT TO RESELL OR DISTRIBUTE THIS
COPY FOR PROFIT.—PUB. RE&. 57, APPROVED MAY 11, 1922

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