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The Commonwealth of Massachusetts.

STATE BOARD OF AGRICULTURE.

ECONOMIC BIOLOGY — BULLETIN No. 38.

THE NATURAL ENEMIES OF BIRDS.

By EDWARD HOWE FORBUSH,
State Ornithologist.

BOSTON:
WRIGHT & POTTER PRINTING CO., STATE PRINTERS,
32 DERNE STREET.
1916.

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The Commonwealth of Massachusetts.

STATE BOARD OF AGRICULTURE.

ECONOMIC BIOLOGY— BULLETIN No. 3.

THE NATURAL ENEMIES OF BIRDS.

Bry EDWARD HOWE FORBUSH,
State Ornithologist.

BOSTON:
WRIGHT & POTTER PRINTING CO., STATE PRINTERS,
32 DERNE STREET,
1916.

APPROVED BY
TaerySrate Boarp oF PUBLICATION.

PREFATORY NOTES.

This bulletin has been written to exhibit the utility of native
natural enemies of birds and to show the misfortunes that might
follow their extermination, as well as to set forth the conditions
under which they may need restraint, and to point out those
species that are believed to be most destructive.

The present strong sentiment for bird protection, commend-
able as it is, has resulted in a war of extermination against
the enemies: of birds that may, in time, defeat its own ends.
Bounties are paid on the heads of predatory creatures by in-
dividuals, towns, counties and States. Farmers, sportsmen,
gunners,- game keepers, game commissioners and wardens join
with bird: protectionists in destroying indiscriminately all
creatures that are believed to kill birds or destroy their eggs or
young, and the high and increasing prices now paid for furs
offer an incentive to the trapper to pursue the fur-bearing
animals as never before. It is: true that some of the more
crafty birds and mammals, such as the fox, the Cooper’s hawk
and the crow, may become too numerous and too destructive
to bird life under some conditions, and that certain natural
enemies of birds iutroduced by man from foreign countries,
such as the cat and the English sparrow, persecute birds ex-
cessively at times and in certain places, but the majority of
the larger and more destructive native enemies of birds always
are held in check by the gunner, the farmer and the trapper,
through motives of self-interest, and with the constant increase
in the numbers of game preserves and bird preserves there is
danger that we shall overdo the destruction of so-called ver-
min and thereby bring about serious consequences.

Much time, thought and care have been given by the writer
of this paper to a study of the relations of birds and their

4

enemies, and the experience of many other observers has been
drawn upon in preparing this bulletin. Nevertheless, it may be
noted that the statements concerning the economic value of
the various creatures as set forth in these pages are supported
by comparatively little evidence. Thus they lack the apparent
authority that a fuller presentation of the evidence would have
given them. Had the original plan been followed many more
pages might have been filled with material fully confirming
the conclusions arrived at, but lack of space forbade, and it was
impracticable to secure the publication of the bulletin except
in its present abridged form. Therefore, the statements and
recommendations made and the conclusions drawn should be
taken as the judgment of an observer who, having opportunity,
has endeavored to inform himself fully, and who is confident
that his conclusions have value as guides to all who seek to
protect birds.

The names of mammals given in this bulletin have been brought
down to date through the kindness of Dr. Glover M. Allen.
Those of North American birds have been taken from the
“American Ornithologists’ Union Check-list,” third edition
(1910). Other zodlogical names are such as are given in the
various publications quoted or cited.

CONTENTS.

Introduction, . ‘ 4 A 4

Natural enemies regulate the numbers of animals,

Natural enemies preserve the fitness of the animals on which they prey,
Some natural enemies regulate others,

Useful species may become harmful if not held in check by natural enemies, .

Natural enemies supplement and check one another, :
Natural enemies tend to keep the numbers of birds at their normal limit,
Natural enemies oppose man’s attempts to secure abnormal increase,
When man must reduce natural enemies, .
Man the only exterminator,
Man’s satellites and assistants in extermination,
Introduced domesticated enemies,
Cat,
Dog,
Hog,
Grazing animals,
Brown rat,
Feral enemies,
Mammals,
Red fox,
Minks,
Weasels,
Skunk,
Raccoon, .
Squirrels, .
Red squirrel,
Gray squirrel,
Flying squirrel,
Chipmunk,
Muskrat, .
Mice, i ‘ 2
Field mouse or meadow mouse,
Deer mouse,
Deer,
Birds, 2 i -
Shrikes, . ‘ 2 % F
Grackles or crow blackbirds, , ‘ ‘

PAGE
Feral enemies — Con,
Birds — Con.
Blue jay, . ‘i i : P é ‘ é ‘ ‘ é 34
Crow, : 2 i F F . : F - F ‘ 35°
Hawks and owls, ‘ F ‘ F : ‘ F ‘ 36
Eagles, . : : F * 2 , a ‘ P 37
Introduced bird enemies, . ‘ i ‘ . : ‘ r 37
English sparrow, 3 é * « ‘ P r ‘ 37
Starling, . ‘ “ ‘ 3 r . ‘ 2 38
Ring-necked pheasant, ‘ . 3 - 3 < 38
Minor bird enemies, . és . ‘ : ‘ , 39
Turtles or tortoises, . re : ; i : ; ‘< : 39
Snakes, . “ 4 i , . “ , P 40
Frogs, . , Fi a : ‘ < a 5 46
Fish, : : : ‘ ‘ F 2 4 ri . i 46
Insects, . ‘ ‘ 46
Mistakes made in attempting to ape ihe en enemies ae birds, ‘ 47
The failure of bounty laws, a i ‘ é ‘ ‘ ' 51
Bounty laws do not protect the birds, : i ‘ ' y 53
Bounty laws do not protect the farmer, é * : ; 53
Bounty laws encourage fraud, F ‘ . . 53

Conclusion, . & Pe 4 F ‘ ‘ P P “ ‘ . 58

THE NATURAL ENEMIES OF BIRDS.

3

INTRODUCTION.

It is well known to naturalists that in a state of nature the
natural enemies of any species are as essential to its welfare
as are food, water, air and sunlight. Unthinking people are
slow to realize this, as they see only the apparent harm done
by the so-called rapacious creatures, and fail to observe and
reason far enough to perceive the benefits that such creatures
confer upon the species on which they prey.

Insect-eating, fish-eating and flesh-eating animals are essen-
tial in the great scheme of nature, as they serve to check the
increase and regulate the numbers of other species, which in
turn, when so regulated, tend to perform a similar office for
vegetation. Thus these predatory creatures may be regarded
among the chief controllers of life upon this planet. Man, the
savage, of course must be included among them, and civilized
man, if guided by reason and wisdom rather than greed or folly,
may exercise a beneficial control over many of the lower ani-
mals. In matters relating to the control of wild life, however,
he is only beginning to exhibit reasoning powers somewhat
superior to those of the ape.

NATURAL ENEMIES REGULATE THE NUMBERS OF ANIMALS.

All organic beings naturally produce a superabundance of
offspring and thus tend to increase in: numbers. This is a
provision of nature intended to prevent the extinction of the
species. The rate of multiplication varies greatly in different
animals, but should any form increase without check it even-
tually would come to be so numerous that it would devour
its entire food supply and become extinct from starvation, or
it would compete with other forms which feed on similar food,

8

until all became extinct for lack of food and from diseases
that accompany crowding, starvation and weakness. Natural
enemies tend to prevent this by disposing of the surplus indi-
viduals.

Darwin says, truly, that the struggle for existence is greatest
between individuals or varieties of the same species. Natural
enemies protect a species against itself by keeping its numbers
low enough to prevent serious competition for food.

NATURAL ENEMIES PRESERVE THE FITNESS OF THE
ANIMALS ON WHICH THEY PREY.

Natural enemies also serve to preserve the fitness of a
species by (a) acting to check the spread of disease and (6)
operating to preserve by selection the most active, agile,
cautious or otherwise efficient and mentally and physically fit
individuals.

The spread of epidemics or contagious diseases is checked
by the natural enemies of a species, which readily capture and
destroy those slightly weakened by disease, as such animals
are slower to act or react than those in robust health. Sick
birds, for example, readily are captured, not only by enemies
sly, swift or strong enough to catch healthy birds, but also by
an additional number of slower enemies, which birds in full
vigor would escape with ease.

On this subject Professor Spencer F. Baird of the Smithso-
nian Institution wrote as follows: —

It has now been conclusively shown, I think, that hawks perform an
important function in maintaining in good condition the stock of game
birds by capturing the weak and sickly, and thus preventing reproduc-
tion from unhealthy parents. One of the most plausible hypotheses
explanatory of the occasional outbreaks of disease amongst the grouse
of Scotland has been the extermination of these correctives, the disease
being most virulent where the gamekeepers were most active in destroy-
ing what they considered vermin. ?

Mr. James Henry Rice says that in South Carolina the bob-
white sometimes is attacked by a deadly disease which affects
‘the head of the bird in such a way that it becomes stupid,

1 Letter from Prof. Spencer F. Baird to Mr. J. W. Shorton, published in the Jour. of the Cin-
cinnati Soc. of Nat. Hist., 1882, Vol. V., pp. 69, 70.

9

comes out in the open and lies in the sun. There it is readily
detected and killed by hawks, and thus the progress of the
contagion is stayed.

A similar selection is seen in the removal and destruction by
natural enemies of the dull, slow-witted, deformed or other-
wise unfit individuals which, in the long run, are the first to
be caught and killed, while the active, quick-witted, strong
and well-formed individuals are more likely to escape. A
sharp-shinned hawk dashed into a flock of juncos feeding on
the ground. All escaped by flight but one, which seemed to
have lost its wits or failed to make use of them, and, crouch-
ing close to the ground while its companions were already in
flight, fell a victim to its swift rapacious enemy. Individual
birds which vary widely from the protective coloring of the
species to which they belong are more readily seen, followed
and destroyed by their enemies. Thus albinos, which because
of their whiteness are conspicuous, are weeded out, and the
protective color of the species is kept true.

Evidently, then, the tendency to increase is serviceable in
maintaining a species, provided only that there exist effective
checks to this increase to regulate the species, preserve its fitness
and prevent it from increasing too much in numbers. Natural
enemies provide such checks.

SOME NATURAL ENEMIES REGULATE OTHERS.

In a brief treatise like the present this subject cannot be
handled exhaustively, but there is another way in which natural
enemies benefit the species on which they prey which cannot
be overlooked here, and that is the regulation by some of
them of fhe numbers of certain other natural enemies. For
example, one must count among the foes of birds hawks, owls,
crows, jays, shrikes, foxes, weasels, minks, squirrels, snakes,
rats and mice, but certain large hawks destroy smaller hawks;
large owls destroy smaller owls; hawks and owls kill crows,
jays, shrikes, weasels, minks, squirrels, snakes and rats; weasels
destroy squirrels, snakes eat other snakes, and all catch mice.
If rats, ground mice and climbing mice, lacking these and
other checks, were allowed to increase too much in numbers
they might exterminate most birds by destroying their eggs

10

and young, and this might be equally true of squirrels and
weasels or crows and jays.

Rats and mice, although they must be classed as enemies of
birds, do not constitute a menace to bird life if themselves
held in check by their own enemies, and they perform a great
service to birds by maintaining their own numbers at such a
point that they furnish a great surplus of individuals, and
become the main food supply for hawks, owls and other ene-
mies of birds. Therefore rats and mice, while thus serving as
food to maintain the numbers of birds’ enemies also attract
the attention of these enemies sufficiently away from the birds,
and therefore tend to keep them from becoming too destructive
to bird life.

As Professor Forbes says, the whole series of forces pressing
one on another is like an arrangement of springs, working one
against another, keeping all in place, thus maintaining the
general equilibrium and safeguarding the general welfare.

USEFUL SPECIES MAY BECOME HARMFUL IF NOT HELD IN
CHECK BY NATURAL ENEMIES.

There are certain bounds set by nature to the numbers of
each species within which it serves a useful purpose, but when-
ever through any fortuitous circumstances, such as may arise
by reason of man’s interference, any species overflows this
high-water mark, normal habits may change and severe injury
to other species, even to man himself or his property, may
result.

Animals considered serviceable to mankind, such as insec-
tivorous birds, toads, bats, shrews, etc., are useful if they are
kept within certain limits. The injurious species,-so called,
are mainly those which tend to increase beyond normal bounds.
Then, by reason of abnormal multiplication and consequent
shortage of food, they become destructive. The so-called use-
ful species may become harmful under such circumstances by
changing their food habits when they outrun their usual food
supply. Insectivorous birds, mammals or insects may then
attack grain, fruits or other products of man’s industry. No
one can tell what any animal may eat in case of necessity.
Carnivorous creatures then may devour grass, leaves or fruit.

Lt

Vegetable feeders may prey on other animals. No mammal is
considered more carnivorous than the wolf, yet at times it
feeds voraciously on berries. My son saw a mink eating the
bark and foliage of fruit trees. Wallace says that the carnivo-
rous sable feeds partially on fruits or seeds in winter.

It is a well-known fact that grain-eating birds have strong,
muscular stomachs or gizzards lined with a hard, corrugated
membrane which, with the assistance of pebbles, swallowed for
the purpose, triturates or grinds up the grain or other seeds
eaten, thus practically masticating them in the stomach.
Nevertheless, most birds provided with such a stomach readily
turn to animal food. It is well known, also, that flesh-eating
birds have soft stomachs not fitted for grinding grain, but
many of them will eat grain at need. Hon. John E. Thayer
informs me that. the hooded merganser (Lophodytes cuculatus),
a fish-eating duck, readily learns to eat corn. In the Shetland
Islands the herring gull (Larus argentatus) is said by Dr. Ed-
monstone to live on grain in summer and fish in winter.?
In America our closely allied species has not been recorded as
@ grain eater.

A bird may vary its food habits by necessity, and such a
change may even transform the lining of the:stomach. Dr.
Hunter fed a seagull for a year on grain and at the end of that
time the appearance and structure of the stomach had so
changed that it resembled the gizzard of a pigeon, and Dr. Ed-
monstone asserts that the herring gulls of the Shetland Islands
thus produce a change in the structure of the stomach twice a
year as they shift from grain to fish.

Similar transformations have been observed in the stomach
of a raven and that of an owl, and Dr. Holmgrén has proved
by experiment that the stomachs of pigeons, fed for a long
time on meat, gradually come to resemble those of rapacious
birds.®

When it is shown how all animals tend to increase in num-
bers, and how readily some of the most useful may change
their feeding habits and become injurious under the spur of

1 Wallace, Alfred Russell: Darwinism, 1890, p. 191.
2 Semper, Karl: Animal Life as affected by the Natural Conditions of Existence, 1881, p. 61.

8 Ibid., pp. 67, 68.

12

necessity and competition, it becomes plain that the creatures
which prey on such species and so keep their numbers within
normal bounds are essential to the welfare of all.

NATURAL ENEMIES SUPPLEMENT AND CHECK ONE
ANOTHER.

When we examine broadly the relations of birds and _ their
enemies we find that some species appear far more destructive
to bird life than others. Certain swift hawks, for example,
seem to feed almost wholly on birds whenever they can obtain
them, while other slower hawks rarely take any except - help-
less, sick or disabled birds, but feed largely on small mammals,
such as squirrels and field mice. Thus one species is seen to
take an excess of birds while the other takes an excess of
their enemies, the effect of the activities of one tending to
balance those of the other. Again, a certain animal may be a
destroyer of certain birds and a protector of others. The
skunk, for example, is known occasionally to destroy the eggs
and young of grouse and other birds which nest on the ground,
as well as those of domestic fowls. On the other hand, the
skunk is the appointed guardian and protector of young water
birds, which are unsafe except in shallow waters, where there
are no great fish to eat them. Therefore they frequent such
shallow waters, and there their greatest enemy is the snap-
ping turtle. Wherever these great turtles are numerous practi-
cally no young water birds can be raised, as these cold-blooded
monsters hide in the mud of the bottom or swim under water,
and pull down the young birds by their feet.

During four summers I watched many of these turtles
depositing their eggs and burying them in the earth near the
shores of a river, and in every case within twenty-four hours
the skunk unearthed and ate every egg laid. Where skunks
are numerous it seems impossible for any snapping turtles’
eggs to hatch, but where skunks have been extirpated turtles
increase rapidly in numbers and in time prevent the multipli-
cation of wild ducks or geese.

Although the turtle is an enemy of wild fowl, it may un-
wittingly befriend the ground-nesting birds locally by provid-
ing the skunk with a tempting supply of turtle eggs at a time

13

when the eggs of the ground birds are in the nest, and thus so
occupying its attention and attracting it away from birds-
egging as to save many early broods of birds.

The marsh hawk (Circus hudsonius) feeds to some extent
on marsh birds and their young, but a much larger part of
its food consists of meadow mice and frogs. These mice cer-
tainly would be very destructive to young birds were they
not held in check, and large frogs are known to swallow the
young of water birds. Marsh hawks and other enemies prevent
many frogs from reaching a size when they would be danger-
ous to young birds.

The larger hawks feed commonly on snakes, which are known
to be destructive to birds. Even the rattlesnake is a common
prey of the large red-tailed hawk (Buteo borealis).

NATURAL ENEMIES TEND TO KEEP THE NUMBERS OF
BIRDS AT THEIR NORMAL LIMIT.

Under natural conditions, wherever man and his satellites —
cats, rats, dogs, hogs, goats, etc. — have not interfered with
the balance of natural forces the native natural enemies of
birds do not tend, on the whole, to reduce the numbers of any
species to a point much below that at which its natural food
supply will maintain it. Any species having a bountiful food
supply constantly tends to increase rapidly in numbers, and
natural enemies and meteorological checks are necessary to
keep its increase below the limit of its supply of food. If for
any reason these forces were unable to do this, and a species
became too numerous, starvation and disease would follow.

A school of writers has risen of late who refer to the natural
enemies of birds as far more destructive than the hunter, and
assert that it is useless to attempt to protect birds and increase
their numbers anywhere unless natural enemies (which they
denominate as vermin) be first destroyed. It even is asserted
positively that if a certain tract of land be set aside, and all
shooting upon it be stopped for a series of years, the game
and birds will lessen rather than increase, because of the un-
restrained destructiveness of their natural enemies. This con-
tention apparently is not supported by facts.

If we go back to the times of the early settlers we find that

14

birds and game were remarkably numerous, far more so than
now, and that not only were eagles, hawks, owls, skunks,
weasels, raccoons and other foes of birds far more abundant
then than now, but there were also pumas, wolves, lynxes,
bears and ravens, which are now rarely or never found in
southern New England. It must be accepted as a fact that the
natural enemies of birds did not then tend to diminish their
numbers. Going back only to the days of the civil war we
find that in the southern States, when white men were practi-
cally all in the army, when negroes had no guns and when very
little hunting was done, game increased to enormous numbers
in spite of its natural enemies. .

In 1877-78, when I was on the Indian River, Florida, game
was more abundant than I have ever seen it anywhere since.
Hosts of wild fowl blackened the waters. Bobwhites and wild
turkeys were plentiful, and myriads of herons, egrets, shore
birds and land birds were seen, some of which are now nearly
extinct. But eagles were more than common, so common that
a collector secured nearly 100 sets of their eggs. Seven nests
of the great horned owl were found in a limited region on
Merrit’s Island; barred owls and hawks were numerous and
breeding; raccoons, lynxes and opossums were abundant; while
bears, panthers and, alligators were so common that, allowing
such creatures to be game exterminators, it would seem an
unfavorable country for game. All these animals have been
much reduced in numbers now, but the game also has decreased
enormously.

We are told that in France to-day (1916), now that nearly
every able-bodied man is in the army and little is done to
protect the game or to destroy vermin, game has increased so
since the war began in 1914 as to become a menace to agri-
culture.

These instances tend to disprove the contention that the
natural enemies of birds, and not the hunters, are responsible
for the decrease of birds and game. They give no support to
the theory, so often advanced, that it is necessary to shoot
into the coveys of game birds to “break them up” in order
that the individuals may pair and breed. It may be that
hawks and other natural enemies attend to such breaking up

15

of flocks as is necessary. In any case, the birds breed rapidly
under natural conditions when undisturbed by man. If birds
and game are below their normal numbers in any region’ they
will increase if protected from poachers, lawbreakers, cats and dogs,
under a law prescribing a long close season. If they do not, it is
a sure indication that adverse human influences are at work.

Darwin said that if not one head of game were “shot during
the next twenty years” in England, and if at the same time
no vermin (natural enemies) were destroyed, there would in all
probability be less game than “at present,” although hundreds
of thousands of game animals were then shot annually. But
Darwin spoke of a probability, not of a jact observed. He was
merely stating this probability to sustain one of his theories.
Even if such a thing might have been probable in England,
the conditions there, under a system of game preserving by
the landowners, were absolutely different from the more natural
conditions obtaining here; and if recent articles in the press
can be relied on, it is a fact that since England has been re-
cruiting by wholesale for the war, — sportsmen, keepers and
poachers having gone to the front,— and since shooting has
been given up, the game in England and Scotland has in-
creased rather than diminished. But it must be borne in
mind that whereas the natural enemies of a species tend to
allow an increase in its numbers up to nearly the limit of its
food supply, they tend to decrease them after that limit is
reached, as the birds that first feel the effects of want, being
weak, are first caught and killed, while the well-nourished
birds survive.

If nature is undisturbed, therefore, all the birds are reared
and maintained that the land will support, but when civilized
man steps in and disturbs the natural arrangement and bal-
ance, then, and perhaps then only, the natural enemies of birds
may become unduly destructive, and must be checked.

é

NATURAL ENEMIES OPPOSE MAN’S ATTEMPTS TO SECURE
ABNORMAL INCREASE.

Whenever man, in poultry raising or gamekeeping, attempts

to produce, by excessive feeding and artificial means, more

birds to the acre than the land naturally will support, nature

16

brings her destructive forces to bear against the project. The
natural enemies of game and poultry, finding in the crowded
birds a numerous, easily accessible source of food, attack eggs,
young and adults, and unless every resource is used to pro-
tect them, the poultryman, the sportsman or the gamekeeper
will reap neither pleasure nor profit from his venture in propa-
gation.

Bearing in mind that only when man steps in and in some
way disturbs the biologic balance does it become necessary for
him to destroy the natural enemies of birds, let us inquire
under what circumstances this destruction may be proper.

WHEN MAN MUST REDUCE NATURAL ENEMIES.

Man must reduce (not exterminate) certain natural enemies
of birds: (1) when he attempts to rear poultry or game birds
in excessive numbers; (2) when, because of the disturbance of
the biologic balance caused by extensive agricultural opera-
tions, he needs to increase the number of insectivorous birds
beyond what the land naturally would support; (3) when the
most sagacious natural enemies of birds, like the fox and the
crow, — their own enemies having been reduced or exterminated
by man himself, — take advantage of the extra protection and
food afforded them in civilized communities and thus become
too numerous and too destructive; (4) wherever man hunts
and destroys wild game he may -also reduce somewhat the
numbers of the enemies of the game and thereby relieve the
game of a part of the. pressure brought to bear against its
increase. In all such cases discrimination must be used, and it
is unsafe to reduce too far the numbers of any but the most
powerful predatory animals.

MAN THE ONLY EXTERMINATOR.

It is now believed that even before historic times man be-
came the greatest natural enemy of birds and the chief exter-
minator of species. There is every probability that giant Pleis-
tocene birds, such as the moas of New Zealand (the largest
being able to reach a height of twelve feet) and the Apyornis
of Madagascar, were exterminated by primitive man.

There is no evidence, however, to sustain the belief that

,

17

primeval man ever exterminated any bird that possessed more
than very limited powers of flight. Most of the species that
were extirpated by the aboriginal inhabitants of all countries
were great flightless land and water birds. The swift flying
birds were able in a great measure to escape the destructive
weapons of early man, and it has remained for civilized man
to create a demand for dead birds in great quantities and to
produce weapons to strike unerringly the bird in the air.
Thus the nineteenth century saw the extinction of far more
species of birds than any other within historic times.

Since the beginning of history, man (assisted by his satellites
the cat, dog, rat, hog, etc.) has been responsible, directly or
indirectly, for the extermination of most if not all of the species
of birds that have disappeared from the earth; but I have re-
ferred to this at length in other papers! and cannot repeat
my observations here.

MAN’S SATELLITES AND ASSISTANTS IN EXTERMINATION.

Man’s protégés, which, by reason of his care or protection
and because of introduction by him into new countries, become
unduly destructive to bird life, consist first of the species that
he domesticates or partially domesticates and then allows to
run at large. Such are the cat, the dog and the hog, in the
order of their significance. Next in importance are the crea-
tures which he introduces intentionally or inadvertently from
one country into another, and which, being free in the new
country from the restraint exercised in their native land by
their natural enemies, increase unduly. Such are the rat,
the mongoose, the English sparrow and the starling. Finally
we may consider the domesticated animals which ordinarily
are confined or controlled, such as the horse, ox, sheep and
goat. The hog may be included in this group in New Eng-
land, as hogs are not allowed to run wild here.

1 Special Report on the Decrease of Birds and its Causes, pp. 477-486; Useful Birds and their
Protection, pp. 356-361; Game Birds, Wild Fowl and Shore Birds, Part II., pp. 399-494.

s

18

Introduced Domesticated Enemies.
Cat (Felis libyca domestica).

The cat, because, of its numbers and intelligence, has no rival
in this country as a bird destroyer, except perhaps the dog in
States where there is no dog tax. Undoubtedly there are other
mammals and some birds which kill more birds individually
than the average cat; but the species, including strays, vaga-
bonds and those that have run wild and bred in the woods,
has become far more abundant now than any other animal
of equal individual destructiveness. I have already devoted a
bulletin to this subject (Economic Biology, Bulletin No. 2,
Massachusetts State Board of Agriculture, 1916), and cannot
spare more space to it here.

Doe (Canis familiaris).

_ The dog is believed to be individually even more deleterious
than the cat to certain birds which breed on the ground, but
it is not so skillful and crafty as the cat and cannot climb. In
Massachusetts dogs are not one-tenth as numerous as cats,
and most of them are kept under better control, while many
are confined to buildings or kept under the eyes of the owners.

Dogs are readily taught to obey their masters, while cats
are not, and the dog license law has reduced tremendously
the number of dogs kept as well as the number of vagrant
dogs. In South Carolina, where there is no dog license law,
Miss Belle Williams, secretary of the State Audubon Society,
who has conducted a painstaking investigation of the decrease
of birds, finds that dogs are terribly destructive to birds in
nearly all parts of the State. Indigent negro families keep
many dogs, which are obliged largely to pick up their own
living, and therefore range the fields and woods, eating quan-
tities of eggs and young birds. The conditions in regard to
the dog there are similar to those that obtain in relation to the
cat in Massachusetts. Even here dogs are so numerous that
they have practically ruined the sheep industry, and driven
sheep from New England pastures where once many thousands
grazed. Many dogs here are allowed to roam and hunt at will.
Some owners never feed their dogs meat but permit them to

Esximo Dog.

Any dog allowed to run at large in the nesting season is likely to destroy birds’ eggs and young.
Dogs not fed meat are most destructive. Eskimo dogs are a scourge to bird life. (Original
photograph.)

(‘ydevisoj0yd [eulsQ) *desys Aq pardnaso spurjst uo asnois pue saduvs 9]3780
yeeid UO payeululie}xe Ajavau ussq aABY [eng ‘ainqsed aU} UL S}SeU SPIIG 0} BAIQONYSap ase Bulfduresy ay} put ssess oy} Jo Surddoso oy J,

“saulg AOULSEC SIVWINY DNIZVUL

19

run in the fields and woods, where they kill and eat young
birds, birds’ eggs, mice, squirrels and any living thing that
they can find. One might as well turn out a ravenous wolf
to prey on eggs and young birds as to loose such a dog in the
country. In the winter some dogs are almost as expert as the
fox in catching ruffed grouse in the snow. Others become
skilled in picking up the young in spring, and will snap up
young bobwhites almost as quickly as a toad will catch a fly.
There are instances on record where dogs, given their liberty
on islands occupied by breeding sea birds, have destroyed all
the eggs and young. In the North the Eskimo dogs, allowed to
forage for themselves, are very destructive to land birds and
sea fowl.

No dog should be permitted to hunt alone during the breed-
ing season of the birds. There is no reason why a dog should
be allowed at large in the country at this time except under the
care and control of the owner, who should be compelled by law
and public sentiment to manage a dog just as he is compelled
to keep within bounds larger domestic animals.

Hoe (Sus scrofa).

The hog is not allowed to roam at large in Massachusetts,
but when hogs are turned out in large enclosures they exter-
minate or drive out practically all animal life occupying the
ground within the boundaries of their pasture. In some parts
of the South, where hogs are allowed to run practically wild, they
destroy the eggs and young of birds that nest on the ground.

Grazing ANIMALS.

Horses, cattle, sheep and goats often trample the nests of
birds or the young before they are able to fly well. The crop-
ping of the grass, where such animals are pastured intensively,
exposes the nests of ground birds to enemies, and sometimes
results in the extirpation of species over wide areas. Goats
when introduced on islands have been known to destroy the
shrubbery, thus removing all cover and driving out the birds
that hide or nest in such cover. Close pasturing by sheep
has a similar tendency.

20

Brown Rat (Rattus norvegicus).

The status of the rat is peculiar. It may be domesticated
but ordinarily it is neither a wild nor domesticated animal but
is domiciled as a parasite on mankind. Rats when numerous
destroy eggs and attack the young of many species of birds.
I have treated this subject in Bulletin No. 1 of this series.

FERAL ENEMIES.
Mammals.

The larger native carnivorous, mammalian enemies of birds,
the bear, puma and wolf, have been extirpated from Massa-
chusetts and need not be considered. The two species of lynx,
or so-called wildcats (Lynz ruffus ruffus and Lynx canadensis
canadensis), are now rare and local, and where they are found
they feed more on mammals, such as hares, than on birds. Of
all the larger native enemies of birds, next to the wild house
cat the fox is the most important because of its ability to
maintain itself in considerable numbers in a thickly settled
country.

Rep Fox (Vulpes julva fulva).

In the natural order of things the fox, no doubt, is beneficial
as a regulator of the numbers of mice, insects and other small
animals, but we have destroyed its natural enemies, and it
is so crafty that it is able to exist, thrive and multiply
unduly in settled communities where, unless held severely in
check, it may become destructive to poultry, game and birds,
and so detrimental to the public welfare.

If I were to consult only my own experience in tracking foxes
for many miles and studying their food habits I should regard
them as almost wholly beneficial, and as living mainly on mice,
insects, refuse scraps and wild fruit, varying their fare with an
occasional cat or a woodchuck, but many correspondents have
sent me notes which go to show that foxes when numerous
may become nuisances or even pests. I have published else-
where a little of this evidence.!

1 Special Report on the Decrease of Birds and its Causes, fifty-second annual report, Mass.
State Board of Agr., 1904, pp. 490-498.

21

Foxes have been seen to follow people who were photo-
graphing or observing. birds’ nests, and the nests were robbed
after the investigators had passed. Foxes find and destroy
the eggs and young of many ground-nesting birds, including
those of the ruffed grouse and bobwhite. They spring after
birds on the wing and catch them. Ruffed grouse, woodcock
and bobwhites have been found in fox stomachs. They catch
both young and old game birds in summer, even wild ducks.
In winter they catch grouse, pheasants and bobwhites under
the snow, or under the lower branches of coniferous trees where
the birds take shelter for the night.

Long experience of many observers leads to the belief that
where foxes are too plentiful game becomes scarce and when
foxes are reduced in number game increases. Quantities of
feathers and other remains of birds, particularly those of the
ruffed grouse, have been found where fox dens have been
opened. In a region in western Massachusetts where foxes
were plentiful I was unable in two days to find a ruffed grouse
or hear one drumming, and the only traces of the species that
could be found were feathers at the entrance of two fox dens.
Although it is true that foxes live chiefly on mice and insects,
they destroy many species of birds, domestic fowls (including
turkeys, geese and pigeons), also lambs, fawns, cats, young
pigs, porcupines, hares, rabbits, woodchucks, muskrats, mice,
moles, shrews, frogs and insects. Foxes often kill numbers of
turkeys and chickens that are allowed to run at large in or
near woods or to roost in the trees. In one such case that
came under my observation a poultryman lost more than two
hundred hens and chickens in a short time and gave up the
business. Foxes were the only creatures seen to take them.
Those who doubt the destructivenesss of the fox should con-"
sult the “Diseases and Enemies of Poultry,” by Drs. Pearson
and Warren, published by the State of Pennsylvania. All that
is said here of the red fox will apply to the Cross fox and the
black fox. The northern gray fox (Urocyon cinereoargenteus
borealis) is almost equally destructive to birds and game, but
is not common in Massachusetts.

22

Mings (Mustela vison vison and Mustela vison lutreocephala).

The mink may be regarded as a large, robust, water-loving
weasel. It feeds largely on fish, mussels and other aquatic
forms of life, on muskrats, rats, mice and other small mammals,
birds, earth worms and possibly insects, but the birds that it
takes are believed to be mainly rails, ducks and similer species
that inhabit the marsh. Its predilection for fresh fish is such
that it sometimes becomes a serious detriment to the industry
of fish culture, as it is fond of trout and kills more than it can
eat.

People living on streams that are frequented by ‘minks occa-
sionally lose large numbers of ducks or chickens. Minks have
been known to kill from thirty to forty of these fowls in a
single night. The high price of its fur acts as a continual
bounty for the destruction of the mink, and its numbers are
not very large.

WeasEts (Mustela noveboracensis noveboracensis and Mustela
Cicognani cicognanit).

In all my observation and research very little conclusive
evidence has been found to convict weasels of destroying wild
birds. European naturalists assert that weasels kill birds and
suck eggs, but give little proof of it, and American writers
have passed their statements along. Field observers seem to
have seen very little destruction of birds by weasels. I have
tracked and followed weasels for miles, and never yet have
seen any evidence of the killing of a wild bird or the destruc-
tion of nests or eggs. They are, nevertheless, in proportion
to their size the most rapacious of all mammals that roam the
woods. Their thirst for blood seems insatiable, and, like the
domestic cat, they often kill apparently for the mere joy of
killing or for the pleasure of sucking blood, leaving their vic-.
tims to lie where they fall. No fiercer slayers exist. Size con-
sidered, their courage and strength are greater than that of
the lion or the tiger. They follow their prey by scent, and are
as keen as bloodhounds on the trail. Their chief food supply
in my experience consists of rats and mice, particularly white-
footed mice, and many insects. With the possible exception

‘ 23

of some of the hawks and owls, the weasel family seems to
contain the world’s greatest mouse destroyers. Weasels follow
mice into their holes and kill enormous numbers. Wherever
they appear they slay or drive out all rats, and in these re-
spects they appear to be the most useful of all mammals.
Grain stacks and barns filled with grain are almost always
infested with swarms of rats and mice, but let a weasel or two
appear and the rodents quickly vanish. When mice and rats
grow scarce, however, weasels often have been known to enter
poultry houses and kill considerable numbers of fowls. Indi-
viduals sometimes become pests on the game farm or preserve.
Weasels can enter such small holes that only mouse-proof build-
ings and pens are a sure protection against them. In winter
they sometimes destroy many hares or rabbits, and trail or
hunt down ruffed grouse or bobwhites in or under the snow.
Hence they are regarded as pernicious by the sportsman and
are killed at sight. I have not known them to be destructive
to any squirrel except the chipmunk, which they sometimes
exterminate locally, but weasels can climb well, and probably
they .destroy some young birds in their nests, although I have
no conclusive evidence of this. Mr. Hugh Malloy of Freeland,
Pennsylvania, found thirteen out of fourteen newly hatched
ruffed grouse chicks which he believes were killed by a weasel.
He slew the weasel and thus, he says, saved one chick.1 Mr.
A. W. Rhoads of Wilkesbarre, Pennsylvania, has known a
weasel to destroy eleven out of thirteen ruffed grouse eggs
about to be hatched. Dr. J. L. Warren avers that he has
twice known weasels to kill small birds,’ and tales are told of
weasels springing up like a cat or a fox and catching low-
flying birds or young birds in flight. In nature the weasel no
doubt serves a useful purpose in keeping down the increase of
rats, mice and insects, but it is not a creature to be tolerated
about a poultry yard, game farm or game preserve.

1 Pearson, Leonard, and Warren, B. H.: Diseases and Enemies of Poultry, 1897, p. 430.
2 Ibid., 1897, p. 432.
+ Ibid, p. 439.

24

Skunk (Mephitis putida).

This much detested animal is looked upon commonly as a
nuisance and a pest, but every naturalist who has made a
study of its food and food habits has come to regard it as
useful if not indispensable to the farmer. Its animal food
consists largely of rats, mice, snakes, frogs, turtles’ eggs and
insects; it is fond of refuse animal matter and will feed on waste
meat or carrion. Occasionally it takes the eggs from under
a sitting hen not properly shut in at night, and has been known
to kill and eat both fowls and chicks. I fed two skunks regu-
larly on garbage in a henhouse for weeks where forty fowls
roosted two and one-half feet from the ground. The skunks
killed mice and rats but never troubled the fowls. Later a
pair of skunks reared their young in a yard of about one
acre, fenced in by chicken wire in which were several hundred
chickens. They never touched a chicken. In all my experience
I have only once known a skunk to break up a nest of a wild
bird. The bird was a ruffed grouse, and I saw the skunk
eating the eggs while the bird hovered close by. I have been
able to learn of but one other such case where the skunk was
actually seen to destroy the eggs. Nevertheless, the animal is
accused continually by gunners and sportsmen, and it is very
destructive to turtles’ eggs. Its animal food in summer, how-
ever, consists largely of noxious insects. It spends the greater
part, of its time in turning over stones and clods under which
insects hide, in digging out the white grub of the May beetle,
and in taking from the foliage such pests as the Colorado
potato beetle. Any one who examines the dried droppings of
the skunk will find them filled with remains of insects. It is
rather remarkable that this animal, slow and clumsy as it is,
has learned how to catch mice and rats. It is practically
unable to capture adult wild birds, and its fur is now valued
so highly that it is not likely to become too numerous.

2 Raccoon (Procyon lotor lotor).
There is some evidence to the effect that the raccoon robs
birds’ nests, but it is not numerous enough now in settled
regions to be very destructive. Its fondness for green corn

PEST im A CONSPCUoE

WARNING

Song and insectivorous
birds. gulls. terns and herons.
as well as their nests and
(ges. are protected by the laws
of Massachusetts. The PEN-
ALTY tor a violation of the
lus ds a tine of TEN DOL-
LARS tercach birddestroy ed
and cach nest disturbed.

* & AuduPon Sasets

aitheiogtsts aion

Kime Avenue See Yok ony

ms Mir ‘ayieind ty regent shdatnons A (Sia Wee te ing
Meee bees bok kek ios Comminnhen Bale Poem feain

Tue Rep SquirREL 1s DestRuctivE To Birps.

The squirrel shown here cleaned out a flicker’s nest, but has not killed any young birds since.
(Photograph by Walt F. McMahon.)

25

has not endeared it to the farmer, and the sportsman and
angler believe that it destroys game and fish. Add to these
alleged reasons for its destruction the increasing price of its
skin in the market, and we can see why the “coon” is not
destined long to be a great factor as an enemy of birds, except
possibly on lands where all animals are protected.

SQUIRRELS.

Semper considers squirrels the greatest enemies of “our
singing birds, whose eggs and young they devour in great
quantities,” 1 but he probably refers to European species. Squir-
rels compete with birds for nesting places and food, destroying
their nests, eggs and young, and are said even to catch and kill
adult birds, but this must be very uncommon, as it has been
very rarely observed. Apparently there are many squirrels
that do not attack birds. At my place at Wareham, Massa-
chusetts, battles between birds and squirrels are frequent, and
many birds’ nests in or near woods frequented by squirrels
are pillaged, but at Concord, on the estate of Mr. William
Brewster, I have known only one nest to be robbed by squir-
-rels in four years, and have seen but two pairs of birds attempt
to defend their nests against squirrels. There I have seen a
red squirrel look into a bird’s nest without. any objection from
the parent birds, which were close by, but at Wareham the
presence of a squirrel in a tree inhabited by birds is resented
by them at once. Where birds attack squirrels it is safe to say
that there is a reason for it, but where birds never molest squir-
rels in nesting time it is probable that the squirrels are inno-
cent of nest-robbing. Ordinarily, however, squirrels cannot be
tolerated in large numbers where it is purposed to increase

birds.

Red Squirrel (Scturus hudsonicus loquaz).

The red squirrel everywhere has the reputation of a bird
destroyer. Many people have reported it as eating eggs and
young birds. One was seen on my place in the act of eating
the brains of a young catbird. Another, taken from its nest
in a bluebird box when so young that its eyes were still closed,

1 Semper, Karl: Animal Life as affected by the Natural Conditions of Existence, 1881, p. 59.

26

and then reared by hand until nearly full-grown, when released
climbed an apple tree to a robin’s nest, took a young bird and
ate out its brains. The red squirrel appears to be as fond of
meat or fish as is the cat. It eats the trappers’ baits, gnaws
the carcasses of animals that he has skinned, takes meat, suet
and other fats put out for birds in winter, and, like all other
squirrels, feeds more or less on insects in spring and summer.
Many of my correspondents have reported that they have
seen it robbing the nests of birds.1 Two have noted it as
catching adult birds in the air as they flew at or by it, but in
all my experience in the woods I have not been able to corrob-
orate this. There is some evidence in favor of the theory that
individual squirrels which acquire the habit of robbing birds’
nests are the chief culprits. I am now inclined to the belief
that nest-robbing sometimes becomes a habit with certain
squirrels, and that in some places the habit is communicated
to many individuals and perhaps over considerable areas, while
in other localities it is not common. Such practices are likely
to spread as a consequence of any undue increase in the
numbers of squirrels, and are in a fair way to become wide-
spread, when such increase begins to outrun the normal food
supply. This squirrel is said to destroy the eggs of the ruffed
grouse, and Dr. B. H. Warren records the killing of an indi-
vidual in the act of carrying off a small chicken from a coop.

Gray Squirrel (Sciurus carolinensis leucotis).

We have protected gray squirrels by destroying their greatest
enemies, the red-tailed hawk and the great horned owl. There-
fore, wherever shooting is forbidden the gray squirrel may be-
come numerous, even in some cities, where there are trees

1 Most writers on the habits of mammals seem to agree that the red squirrel is a nest-robber.
John Burroughs says that he thinks that the mischief it does can hardly be overestimated (Signa
and Seasons, 1886, p. 92). Stone and Cram say that in summer it robs birds’ nests high and low
(American Animals, 1902, p. 173). Ernest Ingersoll asserts that it destroys far more birds’ eggs
and young than any other squirrel, and that not even the Baltimore oriole’s nest is safe from
it (Our Animal Competitors, 1911, p. 129), Ernest Harold Baynes avers that he has known so
many nests destroyed by it that he will not allow one of these animals in any place where he is
trying to attract birds ((Wild Bird Guests, 1915, p. 28). On the other hand, Mason A. Walton
asserts that in his neighborhood birds do not fear the red squirrel, which occasionally examines
nests but never, so far as he has observed, molests them. He tells of one which investigated a
chickadee’s nest frequently and did no harm, and another which examined a vireo’s nest in which
young were later safely reared. He asserts that nineteen nests built near his cabin in one season
were not troubled by squirrels (A Hermit’s Wild Friends, 1908, pp. 68, 70, 98),

Gray SquiIrREL.

An enemy to birds that nest in hollow trees, driving them away from their nesting places and
sometimes killing the young. (Photograph by Walt F. McMahon.)

27

enough to serve as a safe refuge. The gray squirrel is not
regarded generally as detrimental to bird life, but in some
respects it is more so than the red squirrel. Wherever both
species are protected in Massachusetts the gray squirrel in-
creases several times as fast as the red, as it has two litters
annually, while the red squirrel has but one. Young gray squir-
rels may be seen in the woods in June and in September, and
may be found in the nests in May and in August, even in the
northern part of the State. Although I have not heard of a
second litter on the higher elevations of western Massachusetts
it would not be surprising if even there two were raised in the
lowlands. ‘Much has been written about gray squirrels being
driven out or mutilated by the red, but in my experience they
have occupied the same woods without serious friction. The
grays, if protected from gunners, constantly increase in num-
ber, until they have utterly destroyed quantities of corn, pump-
kins, nuts, pine seed, apples, pears, strawberries and other
useful products. Birds feed lavishly on Juneberries, but in
some places where gray squirrels are numerous it is useless to
plant Juneberries for the birds, as these squirrels often take
all the berries before they are ripe enough to attract birds.
Thus squirrels compete with birds for food.

This species when numerous is perniciously successful in
driving out birds from hollow trees. All species of arboreal
squirrels occupy hollow trees for nesting purposes, and where
gray squirrels are abundant, bluebirds, tree swallows and other
birds that build in tree cavities will find little chance to nest
unmolested. If we provide nesting boxes for birds, squirrels
keep them out or drive them away, enlarging the entrances with
their teeth if these holes are too small for squirrel uses, and
often destroying eggs or young birds.

Near my camp in Wareham a gray squirrel was seen to leap
from a small tree into a bevy of bobwhites, in an apparent
attempt to catch one, and frequently I have seen individual
squirrels chasing small chickens, and have since suspected them
of killing chickens. A friend who kept pigeons in a loft com-
plained that rats got in somewhere and destroyed the squabs,
eating the grain from their crops. As there was no entrance for
rats except a window high up in the building I suggested that

28

this window be protected from climbing animals by sheets of
zinc, nailed on the outside of the building. This was done and
no more squabs were lost, but gray squirrels were seen to fall to
the ground in their attempts to climb or jump into the win-
dow. Years passed without absolute proof of chick killing,
but recently Mr. O. L. Curtis, assistant manager of the great
estate called Seven Gates, formerly the country home of Profes-
sor N. S. Shaler at North Tisbury, told me that many chickens
on the place were killed, as was supposed, by rats, but not
eaten, only the grain being taken from their crops. One of
his men saw a gray squirrel in the act. Mr. sae then
watched, saw a squirrel go into a coop through a hole in the
wire, kill a chicken and eat the grain from its crop. He shot
the squirrel and several more that came to the ‘coop later.
This habit of the gray squirrel probably is exceptional.

Flying Squirrel (Glaucomys volans volans).

Hundreds of nesting boxes for birds that have been put up
in trees in Massachusetts have been occupied by squirrels,
and while the two preceding species have been the chief tres-
passers in most cases, flying squirrels sometimes have outnum-
bered the reds, where the nesting boxes have been put up in
woods. The flying squirrel moves about mainly at night and
little is known about its habits, but I once found one occupy-
ing the recently completed nesting hole of a downy woodpecker,
and suspected that it had robbed the nest. So far as I know,
however, no one has yet convicted the species of nest-robbing.

Chipmunk (Tamias striatus lysteri).

This species is not much complained of as a nest-robber,
and although well able to climb trees it is more at home on
the ground. It is a meat eater and has been known to rob
nests. It is said to swallow young birds. Three observers
have reported this, and Mr. W. L. McAtee informs me that re-
mains of a young bird were found in the stomach of a chipmunk
dissected at the Biological Survey. I have recorded else-
where the killing of a wounded bird by a chipmunk.’ As a

1 Special Report on the Decrease of Certain Birds and its Causes, with Suggestions for Bird
Protection, fifty-second annual report, Mass. State Board of Agr., 1904, p. 505.

29

matter of justice to the squirrels they should be given credit
for great service in distributing and planting the seeds of forest
trees.

Muskrat (Ondatra zibethica zibethica).

Ingersoll names the muskrat among the mammals that rob
the nests of ground-nesting birds.! Dr. Abbott asserts that
muskrats sometimes eat young green herons that fall from
the nest.2, Wounded ducks are said to be attacked occasionally
by muskrats, and some dead ducks are eaten by them, but
beyond this I have been unable to find any evidence that the
muskrat is destructive to birds under normal conditions. What
it may do when in abnormal numbers is shown by recent expe-
rience in Austria, where it has been introduced and is said
to have increased rapidly, devouring wheat and other cereal
crops, fruit and vegetables. It has almost ruined industries
of crayfish and carp breeding; has raided poultry, carrying off
young chickens, and has even attacked game animals. It un-
dermines railway embankments, ruins dikes and seems to have
become a first-class pest. Muskrats normally feed very largely
on vegetable matter and thus tend to prevent vegetation from
choking up ponds and streams. They eat mussels or so-called
fresh-water clams. Ordinarily the demand for their fur will
prevent abnormal increase.

MIce.

The importance of mice as enemies of small birds and game
birds is not generally understood. If not held in check they
may quickly become the most destructive of all the agencies
for the suppression of birds. If an irruption of field mice
should occur in early summer they would destroy the grass
and clover, and the callow young of the small ground birds
that nest in the field would be left unshaded from the hot sun,
which would kill most of them even if they escaped the
swarming, hungry mice or the other enemies to which they
would be exposed. The eggs and young of game birds which
nest on the ground would not escape the latter fate. If deer
mice and pine mice were to increase half as fast as nature

1 Ingersoll, Ernest: The Wit of the Wild, 1906, p. 54.
z Abbott, C. C.: A Naturalist’s Rambles about Home, 1885, pp. 188, 189.

30

provides for their multiplication, hardly a bird’s nest in the
woods would escape them, from the ground to the treetops.
Deer mice are so small and light that they can climb to any
nest where even a squirrel might fail, and they are quite as
fond of young birds as are the squirrels. Field mice of various
species have from four to six litters of young each year, with
from two to thirteen young in each litter, therefore the estimate
by Professor Lantz that a single pair of our common meadow
mice is potentially capable of producing nearly a million young
in five years is not excessive.!

Knowing the capacity of a single field mouse to be from
twenty-four to thirty-six pounds of green vegetation annually,
Professor Lantz calculates that a thousand field mice (which
might ordinarily inhabit a meadow) would require at least
twelve tons of grass or its equivalent each year. A million
would require twelve thousand tons annually. History shows
that under favorable conditions countless numbers are produced
in a few years, and that when such invasions occur they destroy
or ruin grass, clover or alfalfa, hay in stacks, all small grain
growing or in shocks or stacks, garden and hotbed plants, po-
tatoes, beets, turnips, carrots, cabbage, celery and other vege-
tables, apples, pears and other standard fruits, small fruits
and the plants that bear them, orchard trees and shrubbery,
nursery stock, young forest trees, and nearly all kinds of bulbs, '
tubers and roots. These mice ruin lawns and pastures for the
time being, and become at times in the old world the most
important of all pests.

The great swarms of lemmings that have appeared from time
to time on the Scandinavian peninsula, and the destruction
brought about by their numbers, are historic. In my “Useful
Birds and their Protection,” pages 76 to 78, I have noted sim-
ilar occurrences in Scotland and England, and the effectiveness
of owls and other natural enemies of birds in destroying the
pests. Figuier says that in France “Whole districts have been
reduced to destitution by this scourge,” and that the Depart-
ment of La Vendee experienced a loss in two years estimated
at £120,000 (nearly $600,000), caused by these creatures.?

} Lantz, David E.: U.S. Dept. of Agr., Biol. Surv., Bull. No. 31, An Economic Study of Field
Mice, p. 12. 4

2 Figuier, Guillaume Louis: Mammalia, Their Various Orders and Habits, popularly illus-
trated by typical species, 1870, p. 445. ,

31

Already, because perhaps of the excessive destruction of the
enemies of birds and mice in some parts of the United States,
these little rodents are causing serious loss. The greatest out-
break in this country of which I have seeh definite records
occurred in the Humboldt valley, Nevada, in 1907-08. Here
four great ranches suffered an estimated loss of $86,500, and
the damage in the immediate region was estimated at about
$300,000, with injury less severe extending up the river and its
tributaries.!

Field mice when properly held in check by their natural
enemies perform several useful offices. Then, according to
Rhoads, the food of the common meadow mouse (Microtus
pennsyluanicus pennsylvanicus) consists mainly of rushes, sedges,
salt grass and other coarse grasses and weeds, and from 70 to
80 per cent of the whole number of field mice ordinarily live in
bogs and low moist lands, where they do little if any harm,
while those on uplands nearly all confine their foraging to
fence rows, brush patches and neglected places, rarely eating
any except waste grain.”

Thus when in normal numbers they do good rather than
harm, by converting worthless rushes, grains and weeds into a
supply of food for fully two-thirds of the natural enemies of
birds which, by means of the superfluous mice, easily taken,
are fed sufficiently to prevent them from becoming too de-
structive to birds. Exterminate mice and the problems of the
farmer and those of the economic zoélogist would be wonder-
fully increased, but exterminate the natural enemies of mice —
then the deluge. The only effective artificial method of meeting
the great invasions of mice that occur through lack of natural
enemies is to use poison, which is likely to be destructive to birds
and other animals as well as mice. Therefore it is suicidal to
destroy too many shrikes, crows, hawks, owls, herons, bitterns,
gulls, foxes, skunks, weasels and other creatures which feed on
mice, even though they may feed to some extent on birds also.

The two forms of mice which are, perhaps, the most widely
disseminated, and prolific of all native mice are the common
meadow mouse and the deer mouse.

1 Piper, Stanley E.: U.S. Dept. of Agr., Farmers’ Bull. No. 352, The Nevada Mouse Plague
of 1907-08, 1909, pp. 9, 10. °
2 Rhoads, Samuel N.: Mammals of Pennsylvania and New Jersey, 1903, pp. 98, 99.

32

Field Mouse or Meadow Mouse (Microtus pennsylvanicus penn-
sylvanicus).

Rhoads says that under normal conditions only about 5 per
cent of the food of this species consists of animal matter. It de-
stroys some insects and eats dead animals, birds and eggs. Dr.
George W. Field informs me that this species interfered with
some experiments in rearing bobwhites undertaken by the
Massachusetts Commission on Fisheries and Game, as it de-
stroyed many eggs. Whenever the numbers of field mice
increase, so that their food supply is threatened, they will turn
quickly to animal food, eating dead animals, destroying live
ones and even killing and eating one another. I am not aware
that the effect produced upon bird life by these swarms of
mice has been investigated, but it is easy to’ understand that
it must be very serious.

Deer Mouse (Peromyscus leucopus noveboracensis).

The habits of the deer mice, now separated by the system-
atists into several forms, are somewhat like those of the garden
dormouse of Europe. Although quite at home on the ground
the deer mice or white-footed mice are very partial to trees,
and often make their nests in hollow trees or in birds’ nests,
no doubt in some cases depriving birds of their homes. Dr.
Abbott says that they are skillful hunters of birds’ nests, and
that he has known them to rob the nests of the robin, song
sparrow and chewink, and asserts that he ,has seen young
robins, nearly fledged, killed by them. The mice returned to
the nest when the parents were absent and ate the young
birds.!. Mr. M. A. Walton of Gloucester, Massachusetts, wrote
me in detail that he had known these mice to destroy birds on
many occasions. The birds killed were young or injured. When
he placed nests with young birds in his cabin in the woods for
safety over night he found invariably that they were eaten by
these mice unless protected by wire netting. He asserts that
the mice robbed the nest of a white-throated vireo near by
and brought one of the dead young into the cabin. Stone and
Cram assert that these mice appropriate the nests of birds in

1 Abbott, Charles Conrad: A Naturalist’s Rambles about Home, 1885, p. 70.

33

bushes and low trees, and that they have been caught often
in the act of devouring eggs and young birds. Dr. Merriam
says that he has found their nests in holes in trees more than
seventy feet from the ground.? Many nesting boxes put up
for birds in or near the woods are occupied by these mice. It
is fortunate that owls keep them in check. I have no informa-
tion regarding the destruction of birds by pine mice, jumping
mice or any other species, but it is probable that any of them
might destroy birds should their numbers increase unduly, as all
small rodents are likely to become more or less carnivorous
under such circumstances.

Desr (Odocoileus virginianus virginianus and Odocoileus wir-
ginianus borealis).

Dr. George W. Field assures me that deer eat the eggs of
ground birds. It seems probable that if this is the case they
may devour young birds also. Mr. F. C. Walcott quotes Mr.
C. C. Worthington’s statement that thirty-four deer on his
preserve were killed by eating poisoned sparrows. The birds
were found in the stomachs of the dead deer.’

Birds.

Surikes (Lanius borealis and Lanius ludovicianus migrans).

Shrikes or butcher birds are believed to be beneficial. Dr.
Judd of the Biological Survey reports on stomach examinations
of shrikes as follows: —

The food of the butcher bird and loggerhead, as shown by one hundred
and fifty-five stomachs collected during every month in the year, and in
an area extending from California to the Atlantic coast, and from Sas-
katchewan to Florida, consists of invertebrates (mainly grasshoprers),
birds and mice. During the colder half of the year the butcher bird eats
birds and mice to the extent of 60 per cent, and ekes out the rest of its
food with insects. In the loggerhead’s food birds and mice amount to
only 24 per cent. The loggerhead’s beneficial qualities outweigh 4 to 1
its injurious ones. Instead of being persecuted it should receive pro-
tection.4

1 Stone, Witmer, and Cram, W. E.: American Animals, 1902, p. 132.

2 Merriam, Clinton Hart: The Mammals of the Adirondack Region, 1884, p. 263.

3 Job, Herbert K.: The Propagation of Wild Birds, 1915, p. 71.

4 Judd, Sylvester D.: Bull. No. 9, U.S. Dept. of Agr., Div. of Biol. Surv., Cuckoos and Shrikes,
1898, p. 24.

34

Dr. Judd records the killing of a young chicken by a logger-
head shrike which is credited to the “Florida Dispatch,’’! and
Mrs. B. R. Buffham of Roswell, New Mexico, saw a shrike,
probably of the same species, hang up a dead chicken seem-
ingly just out of the shell.? ;

GRACKLES oR Crow Buackpirps (Quiscalus quiscula quiscula
and Quiscalus quiscula eneus).

The purple grackle, which is resident here in summer, is
known to destroy the eggs-and young of other birds at times,
and when in large flocks in autumn it devours corn in the
field. The destruction of the eggs and young of birds by it is
not considered very serious and it is not believed to be very
generally addicted to this habit. Professor F. E. L. Beal made
an examination of the stomachs of two thousand two hun-
dred and fifty-eight crow blackbirds obtained from twenty-six
States.2 Only thirty-seven stomachs contained any trace of
birds’ eggs and, only one the remains of a young bird, but we are
not told how many of the stomachs were taken during that
part of the year when eggs and callow birds are not obtainable.
He concludes that crow blackbirds are so useful that no general
war should be waged against them. They are not protected
by law now (1916) in Massachusetts.

Buve Jay (Cyanocitta cristata cristata).

The blue jay is, at times, even more destructive to the smaller
birds than is the crow. It has been known to attack and kill
adult birds, young chickens and young pheasants, and to eat
the eggs and young of most of the smaller birds. I will ven-
ture to say that every close observer who has watched the
jay long and carefully is familiar with its nest-robbing habits.
It is so sagacious and cunning that it is sure to establish itself
wherever shooting is prohibited, and there it increases apace,
to the detriment of small birds. Jays often become numerous
even in cities, and in recent years have learned to build their
nests about houses in very thickly settled communities, where

1 Judd, Sylvester D.: Bull. No. 9, U. S. Dept. of Agr., Div. of Biol. Surv., Cuckoos and
Shrikes, 1898, p. 21.

2 Nature and Culture, January, 1911, p. 21.

3 Beal, F. E. L.: Crow Blackbirds and their Food, Yearbook, U. 8. Dept. of Agr., 1894, p. 233.

Buvuge Jay at Npst.

Jays destroy the eggs and young of other birds. (Original photograph.)

35

no shooting is allowed. Wherever they become unduly numer-
ous through such protection the small birds are likely to be-
come their victims. In defense of the jay, however, it must
be said that he is an efficient caterpillar hunter, and destroys
numbers of those pests, the gypsy moth and the brown-tail
moth.

Professor Beal, who has dissected the stomachs of more than
two hundred and ninety blue jays, believes this species to be
useful. Remains of small birds were found in only two stom-
achs, and shells of their eggs in only three.1 Dr. B. H. Warren
failed to find any traces of birds or eggs in twenty-three blue
jays stomachs which he examined, fifteen of which were taken
in the nesting season.”

The blue jay is not protected by law in Massachusetts.

Crow (Corvus brachyrhynchos brachyrhynchos).

Ornithologists are divided in opinion regarding the economic
value of the crow. Professor W. B. Barrows, who has spent
more time investigating the crow’s economic status than has
any other living man, wrote for the United States Department
of Agriculture a report on the crow. In presenting it for
publication Dr. C. Hart Merriam, chief of the division, de-
clared that the evidence showed the crow to be beneficial.
Since that time Dr. Barrows has expressed the opposite opinion.
In his work on the birds of Michigan, he states his belief that
the crow is more injurious than beneficial to the farmer.’ In
my report entitled “The Crow in Massachusetts” the facts
for and against the crow were considered and I cannot reca-
pitulate them here.

Whatever may be said about the value of the crow to agri-
culture it is not a good bird for the game farm or bird refuge.
Its habit of robbing the nests of birds from the size of the
sparrow to that of the wild duck or the great blue heron is
well known. It is a habit of crows the world over, and some
individuals are remarkably destructive. Nevertheless, the local
extermination of crows has been followed in more than one in-

1 Beal, F. E, L.: The Blue Jay and its Food, Yearbook, U. 8. Dept. of Aer., 1896, p. 199.
2 Warren, B. H.: Birds of Pennsylvania, 1890, p. 201.
3 Barrows, Walter B.: Michigan Bird-Life, 1912, p. 427.

36

stance by such an increase of grubs and grasshoppers as to
destroy the grass crop over large areas, and it would be very
unwise to allow the extirpation of this bird.

Hawks AND OWLS.

Many hawks are not only useful in nature as regulators of
mammal life but they are beneficial to the farmer by destroy-
ing grasshoppers and other large insects, squirrels, rats and
mice. Among the most useful of all is the rough-legged hawk
(Archibuteo lagopus sancti-johannis), which very rarely has been
known to kill birds, and never, so far as known to me, to
molest poultry. The species is large, flaps and sails rather
slowly, and thus makes a good mark for a shotgun, or, sitting
upon a dead tree or stake, furnishes an excellent target for a
tifle. Many are shot annually in fall, winter or spring, mis-
taken for “hen hawks.’ The number of mice killed by these
birds is enormous, and the shooting of the species is a serious
detriment to agriculture. Nevertheless, farmers often boast of
the number that they have killed and gunners shoot them at
every opportunity. They would much better devote their
energies to shooting vagabond cats, which do far less good
and much more harm.

One can hardly write of the economic relations of hawks
and owls in this country without referring to the work of Dr.
A. K. Fisher of the Biological Survey. During his researches
he has examined the contents of more than two thousand
seven hundred stomachs of these birds, with the result that ;
out of the seventy-three species investigated only six in all the
United States were found harmful, and all the rest were classed.
as beneficial. Omitting the six species that feed largely on
poultry ayd game, two thousand two hundred and twelve
stomachs were examined, 56 per cent of which contained mice
and other small mammals, 27 per cent insects, and only 33
per cent poultry or game birds. Of the six harmful species,
three are so rare that they have little effect, and in New Eng-
land only two, the cooper’s hawk (Accipiter cooperi), and the
sharp-shinned hawk (Accipiter velox), are really common and
generally injurious.! Nevertheless, individual birds of several

1 The goshawk (Astur atricapillus atricapillus), the duck hawk (Falco peregrinus anatum), and
the pigeon hawk (Falco columbarius columbarius) are exceedingly destructive to birds, but are
uncommon in Massachusetts,

37

other species may at times become destructive to poultry or
game, and may have to be killed, but the indiscriminate shoot-
ing and trapping of these birds is likely to do more harm than
good.

The owls, with the exception of very few species, are now
believed to be among the most useful of all birds. They de-
stroy destructive insects and mammals at night which escape
other birds by day. The great horned owl (Bubo virginianus
virginianus) usually is regarded as pernicious, as it destroys
game and poultry, particularly chickens and turkeys when they
are allowed to roost in trees at night, but it is now becoming
rare and should be killed only where it is known to attack
poultry or game. The fact that there are robbers among hawks
and owls is not good ground for exterminating all. Mr. E. O.
Niles records the finding of the remains of one hundred and
thirteen rats on the ground beneath a horned owl’s nest, all
taken within a period of about ten days. It is a habit of these
rapacious birds to regurgitate or reject, through the mouth,
bones, fur, feathers, and other indigestible portions of their
food. Dr. Fisher found about the nest of a barn owl (Aluco
pratincola) four hundred and fifty-three skulls of mice, rats and
other small mammals and only one of a bird.!

EAGLES.

The bald eagle (Halietus leucocephalus leucocephalus) has
been observed to pursue and strike down water fowl on the
wing, and also to catch them on or in the water, but it lives
chiefly on fish, captures few except crippled water fowl and
is now becoming generally rare in New England. The golden
eagle (Aquila chrysaétos) is only accidental here.

INTRODUCED Birp ENEMIES.

The English Sparrow (Passer domesticus).

This is the one bird that if not destroyed or driven away
will dispossess the smaller native birds of all bird houses and
nesting boxes. All who cultivate its acquaintance will learn
eventually the truth of this statement. Like most birds it is

1 Fisher, A. K.: U.S. Dept. of Agr., Div. of Orn. and Mam., Bull. No. 3, The Hawks and
Owls of the United States, 1893, p. 136.

38
serviceable in destroying insect pests, but less so than most
native species.

Like the following species and the domestic cat, it is an in-
troduced species and when allowed at large disturbs the bal-
ance of nature and so makes trouble. As I have already treated
of this bird in Circular No. 48 no more space can be devoted
to it here.

The Starling (Sturnus vulgaris).

The starling is increasing and spreading rapidly, and may
yet prove to be a greater enemy to native birds than the spar-
row now is, but it cannot enter nesting boxes with an entrance
hole one and one-half inches in diameter. Therefore, nesting
boxes for the smaller birds may be made starling proof. It is
said to kill small birds at times. I have already treated of
the bird at some length in Circular No. 45.

Ring-necked Pheasant (Phasianus torquatus).

Whatever may be said for pheasants by the advocates of
the introduction and propagation of these exotic birds there
can be no doubt that if they ever become unduly numerous
they will interfere with native birds. The ring-necked pheas-
ant is a good bird for a game preserve, particularly on land
where no other gallinaceous bird is wanted. It thrives along
the coast, especially near salt marshes where the winters are not
too severe. The border of the marsh is its native habitat, but
on high land where winters are inclement, with heavy snowfalls,
it must be fed and cared for. In winter it feeds on weed seeds,
bayberries and other low-growing fruits and seeds, of which
it eats great quantities and thus deprives bobwhites and other
native birds of their chief winter sustenance. Eyewitnesses
have told me that they have seen the pheasant kill both the
bobwhite and the ruffed grouse. I have seen a pheasant strike
a bobwhite on the head and drive it away from the pheasant’s
feeding ground. As a game bird the pheasant cannot compare
with either of these native birds, and it is not a desirable
species to supplant them with. It will never become very
abundant, however, if the seventy thousand licensed gunners
of Massachusetts have their chance at it annually, and as it is
well adapted to the game preserve it has come to stay. It is
destructive to the gypsy moth and other insect pests.

Tue Birp-KILLING Cat.

The destruction of birds by cats is illustrated in Economic Biology, Bulletin No. 2, published
by the Massachusetts State Board of Agriculture. (Photograph by William L. Finley.)

Tue Snapping TuRTLy,

Destroyer of young waterfowl and wading birds, (See page 39.) (Photograph by Professor
H. A. Surface.)

39

Minor Birp ENEMIES.

Certain exceptional individuals of some species of birds have
been known to destroy other birds even though such habits
are not generally characteristec of the species to which these
predatory individuals belong. There are other species which
occasionally or commonly attack birds but have now become
so rare that they do little harm. Gulls, herons and cranes
may be mentioned as belonging to the first class and eagles to
the second. Some individuals among gulls are more or less
predatory. The herring gull (Larus argentatus) sometimes kills
young birds of its own species, but so far as I know has
not been known to eat them. When short of food, herring
gulls have been known to kill and eat young chickens. The
western gull (Larus occidentalis) and the blackbacked gull (Larus
marinus) destroy the eggs and young of other birds, and Euro-
pean species have been seen to kill small birds, but such habits
seem to be exceptional with most American gulls.

.European herons are said at times to prey upon fledglings
which stray near their retreats (Nuttall). The black-crowned
night-heron (Nycticorax nycticorax nevius) has been seen to kill
ducklings (Crandall), and bitterns are said occasionally to eat the
eggs and young of other birds. The red-headed woodpecker (Mel-
anerpes erythrocephalus), now rare in Massachusetts, has been
accused of being a nest-robber. Bad habits have been attrib-
uted occasionally to cuckoos, catbirds, wrens, orioles and other
small birds, but in most cases they may be considered more or
less individual and unusual.

Turtles or Tortoises.

So far as I have been able to learn only one turtle, native to
Massachusetts, can be counted as an enemy of birds. This is
the snapping turtle (Chelydra serpentina). It has been known
to kill and eat young night herons that had fallen from their
nests, and is considered the greatest enemy of young waterfowl.
It frequents muddy ponds, to which waterfowl resort, and drags
them down by the feet. I have known one in this way to tear
a leg from a living adult Canada goose, which escaped but
afterward died. All who attempt to raise wild fowl in the

40

natural way must first clear the breeding pond of this terrible
enemy; else it will be difficult to rear young birds.

Professor H. A. Surface records the stomach contents of
vineteen individuals of this species. Only one had eaten a
bird.1. It is probable that young ducklings were scarce in the
region in Pennsylvania where these turtles were taken. Hay
found a robin in one stomach.? These turtles often are taken
by a strong fishhook baited with tainted meat attached by a wire
to a strong but springy stake driven into the bank.

The wood turtle or sculptured turtle (Clemmys insculptus) is
reported as taking ducklings and goslings, but I can find no
convincing evidence in proof of the charge. This is a small
turtle and it is probable that most of the birds eaten by it
are such as it finds dead. Professor Surface found remains of
birds in two out of twenty-six stomachs.®

Snakes.

Snakes are carnivorous and insectivorous. It is well known
the world over that they destroy birds, their eggs and young.
Tt has been asserted often that they are able to charm birds and
thus render them defenseless, — a statement hardly borne out by
the facts. Occasionally, careful observers have reported a case
where a bird seemed unable to escape from a snake but drew
nearer and nearer. Mrs. Olive Thorne Miller narrates such
an occurrence in “A Bird Lover in the West” (pages 251 to
253), but as she drove the snake away the observation was
inconclusive. The theory that sometimes birds are attracted
to the head of a motionless snake by its flickering tongue,
which they mistake for a worm or insect, is supported by
good evidence. :

Some snakes seem to live almost wholly or altogether on
forms of life other than bitds, but there are some species so
destructive to bird life that their suppression is important to
the bird protectionist. Ingersoll tells of an African snake that

4 Surface, H. A.: Zodl. Bull., Div. of Zodl., Penn. Dept. of Agr., Vol. V., Nos. 4 and 5, for
August and September, 1908, First Report on the Economic Features of the Turtles of Pennsyl-
vania, p. 129.

2 Ibid., p. 181.

4 [bid., p. 163.

41

feeds so exclusively on eggs that it has a mouth especially fitted
for containing and breaking them.?

There is a genus Dasypeltis among the snakes, the species
of which, native to Africa, are believed to live entirely on eggs.
The eggs are swallowed whole and broken in the stomach,
where teeth which grow out as processes from the vertebre
pierce through the lining of the stomach so far that they seem
perfectly fitted for breaking the eggs that pass through it. If
these are true teeth it is the only instance of their occurrence
in the whole animal kingdom, except in the mouth or on the

INSECTS,
Probably from

Diagram showing the percentages of food items of pilot snake (Callopeltis obsoletus) for the year:
11 per cent red squirrels; 2 per cent opossums; 28 percent birds; 2 per cent birds’ eggs (un-
determined); 434 per cent weasels; 10 per cent meadow mice (Microtus pennsylvanicus); 2 per
cent hens’ eggs; 21 per cent insects (probably from birds); 7 per cent undetermined mammals;
12 per cent mice (undetermined). (After Surface.)

jaws. It may be doubted, however, if eggs form the only

food of these snakes.

In New England the larger and more active snakes are most
destructive to birds, while most of the smaller species are now
considered as beneficial to man on account of their insectivorous
habits. The bird-killing snakes will be considered here in the
order of their destructivenesss.

The pilot snake (Callopeltis obsoletus) should not be confused

1 Ingersoll, Ernest: The Wit of the Wild, 1906, p. 57.

42

with other species, such as the copperhead or the hog-nosed
snake, both of which are known locally as the pilot snake, or
with the black snake, which it resembles in color. This snake
grows from about 50 to 75 inches in length and is lustrous
black above with some of the scales white-edged. It is lighter
but still blackish below. Its ventral plates number about 235,
and it is not venomous. It is found from Massachusetts to

Diagram showing the percentages of food items of pilot snake (Callopeltis obsoletus) found during
the months of June and July only: 46 per cent birds; 1614 per cent mice; 12}4 per cent in-
sects; 834 per cent unidentified mammals; 4 per cent weasels; 4 per cent birds’ eggs. (After
Surface.)

Illinois and Texas, and south through the middle States. It
is one of the largest black snakes, climbs trees rapidly, and I
have seen it run fast over and through the tops of a thicket
of young pines 10 to 15 feet in height. This species, like the
black snake, sometimes will chase a fleeing person, but, in
turn, will run if pursued. It takes hens’ eggs and those of other
birds, climbs to nests, and kills and swallows both old and
young birds, which form a very considerable part of its food
during the nesting season. This and the following species
enter the holes of woodpeckers, destroying eggs, adults and
young, and have been known even to extirpate colonies of
barn swallows nesting on the rafters. Their skill and activity
in climbing are unsurpassed among serpents. Mrs. L. H.

43

‘Touissant of Rio, St. Lucie County, Florida, says that a
black snake (probably of this or the following species) actually
crawled up the weather boards of a house to a window where a
canary, was swinging in a cage, and swallowed the bird, which
so increased its size that it could not get out of the cage.!

Professor H. A. Surface, who has made the most complete
study of the food of the serpents of Pennsylvania yet under-
taken, finds that during the late spring and early summer the
eggs and young of birds form the predominating food of the
pilot snake; later it feeds more on mice, insects, ete. The dia-
grams show this plainly.

The black snake or blue racer (Bascanion constrictor) differs
from the pilot snake in having no white except upon the chin

Diagram showing the percentages of food items of black snake (Bascanion constrictor) for the
year: 25 per cent insects; 15 per cent snakes; 22 per cent field mice; 8 per cent birds’ eggs;
4 per cent rabbits; 4 per cent voles; 714 per cent frogs; 4 per cent birds; 7 per cent mammals
(unidentified); 314 per cent larve of royal moth (Citheronia regalis). (After Surface.) The
percentage of birds for June and July, when the young are in the nests, would be very much
larger; but the insects, mice and snakes eaten go far to balance the destruction of birds.

and throat and in having all the scales smooth instead of
keeled. The ventral plates are about 185 in number. The
snake is lustrous black in color, bluish or greenish below and in
length usually 5 feet or less, although larger specimens have
been taken.

1 The Bluebird, Junior Audubon Monthly, Vol. VII., No. 8, May, 1915, p. 222.

44

The young are grayish olive, with short livid black blotches
or spots. ‘This is the common black snake of New England,
and is found mainly in regions more or less wooded. Accord-
ing to Professor Surface it feeds to some extent on large insects,
but more on other insectivorous creatures, such as small snakes,
frogs and birds, but it is believed to be a destroyer of the
rattlesnake and the copperhead. The following diagram gives
an idea of its food. It is not a creature for the bird protection-
ist to protect. :

Next to the black snake, the house, milk or chicken snake

FIELD MICE

(MICROTUS PENNS YLVANICUS)

VERTEBRATES

Undetermined.

Diagram showing the percentages of food items of milk or house snake (Lampropeltis doliatus
triangulus) for the year: 48}4 per cent field mice (Microtus pennsylvanicus); 20 per cent
undetermined mice; 11 per cent unidentified mammals; 6 per cent snakes; 54 per cent
birds; 3 per cent slugs; 3 per cent jumping mice; 3 per cent undetermined vertebrates.
(After Surface.)

(Lampropeltis doliatus triangulus), sometimes called in Massa-
chusetts the spotted or checkered adder, is believed to be most
destructive to birds. This is a rather slim, active serpent and
may be distinguished from the other species by a series of
small square or rectangular black blotches on its light under
parts. It is so active and so proficient in climbing that it can
go almost anywhere that it is possible for a snake to go. Mrs.
Touissant describes how she saw a snake, apparently of this
species, climb up the side of a building, hook its chin over the

45

top of a window frame, draw its body up and so reach a rafter
of the roof, where it caught a rat hiding there.

The diagrams show the proportions of the different kinds of
food found in fifty-two stomachs of this species examined by
Professor H. A. Surface.

The so-called spreading adder or blowing viper (Heteredon
platirhinos), a non-venomous snake common in parts of Massa-
chusetts, resembling in appearance a viper, destroys birds and
eggs to some extent, but like the rattlesnake (Crotalus horridus),
which also kills birds, is rather slow and not a good climber.
Both these snakes, as well as the different forms of garter

Diagram showing the percentages of food items of house snake (Lampropeltis doliatus triangulus)
found during July and August only: 334 per cent field mice; 3314 per cent mice; 13 per cent
birds; 7 per cent unidentified mammals; 7 per cent snakes; 6 per cent slugs. (After Sur-
face.) Apparently this snake eats mice enough to more than pay for the birds that it de-
stroys, for mice also eat eggs and young birds.

snakes or striped snakes (Thamnophis), feed to a limited extent
on the eggs and young of birds that nest on the ground or in
low shrubbery, as also does the copperhead (Agkistrodon con-
tortriz). This venomous and dangerous reptile has the habit
of lying concealed beneath the dead leaves of the forest floor,
with only its reddish head visible, looking like an acorn amid
the leaves, thus no doubt luring many a bird or squirrel to its
death. Like the rattlesnake it is rare now in New England,
but may still be found in the Blue Hills region near Boston.

46

Even the water snake (Natrix sipedon) is said at times to
rob the nests of marsh wrens and to eat the eggs and young
of rails, but it is not believed to feed commonly on birds.
Probably all field ornithologists of large experience have wit-
nessed the robbing of birds’ nests by snakes. The parent
birds occasionally are killed in defense of their homes, and it
is probable that now and then an adult bird, while feeding, is
surprised and caught by a snake, although I have never known
this to happen. Snakes probably do not require a great quan-
tity of food. Individuals have been known to live without
food for more than a year, and investigators, capturing snakes,
find a large proportion of stomachs empty. The digestion of
snakes is slow, and probably they do not consume nearly as
much food in proportion to their size as would a bird
or even a mammal. Hence they probably are not individually
as destructive to birds as are warm-blooded rapacious creatures,
but where the larger snakes become too numerous they may
exert a serious depressive influence on the numbers of birds.

Frogs.

There are many tales of frogs swallowing ducklings but no
such case has come under my observation. Mr. Robert B.
Lawrence reported that a frog in his brother’s duck pond was killed
after it had devoured a young pin-tail duck, and that, as many
young wood ducks had disappeared, it was believed that frogs
had eaten them.1 This observation is corroborated by others.
Only very large frogs are able to catch and swallow birds
and such frogs should not be allowed in ponds with young
ducklings.

Fish. .

Trout, salmon and other large fish capture young birds which
fall or alight upon the water. Pike and pickerel are so destruc-
tive to the young waterfowl, it is said, that young ducks can-
not live in water where they abound.

¥

Insects.

The insect world is potentially the greatest of all dangers
to bird life. Wherever birds and other natural enemies of

1 Huntington, Dwight W.: Our Wild Fowl and Waders, 1910, p. 88.

47

insects fail to keep down the increase of insect pests, even man
himself becomes unable to protect birds. In recent years I
have seen this illustrated in the increase of the gypsy moth
and the brown-tail moth in eastern Massachusetts, — two first-
class pests introduced into this country in the same region with-
_ out their natural enemies and therefore increasing inordinately.
Native birds and other enemies of insects are not numerous
enough to check their increase. Although State governments,
the national government, towns, cities and individuals are ex-
pending probably a million dollars each year in the effort to
suppress them, although the United States Department of Agri-
culture has introduced and propagated parasites and predaceous
insects, although about fifty species of native birds eat the
moth pests, still their increase and spread go on. Last year I
went over a large tract many square miles in extent where the
leaves had been stripped from the trees. Everywhere the young
birds or eggs in the nests in those trees had been destroyed
by the heat of the sun or exposure to their enemies. In such a
case no young birds can be reared except those on the ground
or those in hollow trees or nesting boxes. Similar irruptions
of grass-eating insects expose the nests of ground birds in the
same way. Birds are among the chief enemies of ticks, but
wherever for any reason the numbers of birds are reduced,
ticks increase and still further deplete the numbers of birds
by destroying their young. This happened in Jamaica after
the introduction of the mongoose, which so lessened the num-
bers of birds that ticks, no longer controlled by birds, destroyed
most of the young birds that escaped the mongoose and ren-
dered it almost impossible to raise domestic fowls on the
island. ;

Birds which nest in colonies often suffer severely from para-
sites, particularly mites, which attack them at night.

MISTAKES MADE IN ATTEMPTING TO CONTROL THE NAT-
URAL ENEMIES OF BIRDS.

In considering the methods of controlling the natural ene-
mies of birds we must divide these enemies into two classes:
(1) Those introduced from foreign countries and which there-
fore tend to disturb the balance of nature, and should be elim-

48

inated so far as possible except when under control, either in
domestication or in captivity; such are the dog, house rat,
ferret, cat, hog, ox, horse, sheep and goat, the English sparrow
and the starling. (2) The native natural enemies, which have
through thousands of years become perfectly adjusted in their
relation to the species on which they prey. These should not
be eliminated, with the exception of those few that threaten
our lives or our material welfare, but should be conserved and
controlled according to our needs. When a species becomes
too numerous it should be reduced in numbers; if too few it
should be allowed to increase. The general and indiscriminate
slaughter of all carnivorous species should not be permitted.
Even the poultryman and the gamekeeper should use some
discretion.

An English gamekeeper felt sure that he had seen barn owls
killing young pheasants, and as chicks had disappeared with
no other visible cause he was told by the master to shoot any
owl that was actually seen to take a chick. He saw a barn owl
swoop down among the young birds, shot it and found that it
had a rat in its claws. It was proved later that it was the rats
and not the owls that had been taking the birds. The game-
keeper had shot a friend. A similar incident happened in New
Hampshire, where a farmer killed a marsh hawk that was sup-
posed to be eating his chickens and found that it had killed a
rat. Some individual barn owls may kill young pheasants.
Some marsh hawks kill birds, and in the Cape Cod region
many birds and chickens are killed by marsh hawks, but the
killing of all birds or all mammals of any species because one
or more individuals have been known to destroy birds or poul-
try is as illogical as would be the killing of all men possessed
of guns, knives or axes because some few are known to be
murderers and others are suspected. Some allowance should be
made for individuality among animals as well as among men.

Millais, in his magnificent work on “British Surface-feeding
Ducks,” relates that in 1884 brown-headed gulls began to in-
crease in the bog at Murthly. The keeper said that the gulls
were killing young teal. Another experienced keeper suggested
that this was probably the work of a single gull. The gulls
were watched; a pair of birds were seen together, one of which

49

began to kill ducklings. Both birds were shot, and no more
‘ducklings were killed that year. In 1890 another pair of gulls
began killing young teal; sixteen were found dead. The two
culprits were shot, and no more young teal were killed that
season. Millais considers that individual gulls are as dangerous
to young ducks as are any of their numerous enemies; and yet
probably only two, or at the most four, of the large number at
the bog actually were doing the killing. Had not the game-
keeper been an intelligent observer, a hundred innocent gulls
might have been shot, and the guilty birds might have escaped,
to continue their nefarious work elsewhere. Millais confidently
advances the theory that a few individual birds do the mis-
chief for which perhaps the whole race is blamed. He believes
that the individual criminal among birds does his work stealth-
ily, and so is seldom observed; that his family is fed on the
results of his rapacity; and that the young acquire similar
tastes and habits, which in time may spread from family to
family and from one community to another. He asserts that
years ago the rooks of southern England were practically in-
nocent of stealing eggs or young birds, though their cousins
in the north were nest-robbers even then. He says that now
there is hardly a community of rooks in the south of England
that does not contain individuals with the nest-robbing habit.

Care and discrimination in the control of natural enemies is
imperative. In destroying carnivorous creatures the gun is a
better weapon than trap or poison. The gunner can discrim-
inate. Traps and poisons destroy both friend and foe. Poisons
should not be used except in the dead of winter and should
then be concealed in hollow trees or logs, or holes in the ground,
or so covered that only the animals for which they are intended
are likely to get them.

It is not the purpose of this paper to describe in detail
methods of controlling and destroying predatory creatures but
tather to indicate the mistakes ordinarily made in using these
methods, the most common of which is the indiscriminate
shooting and trapping of hawks and owls. ‘In general it may
be said that the larger soaring hawks, with long broad wings,

1 Nevertheless, observers agree that the habits of bird-killing and egg-eating are quite general
among certain species of gulls.

50

belong to the beneficial species, which feed chiefly on mice
and rats, while the smaller, swifter hawks, with comparatively
short wings and long tails, which rarely soar or circle but flap
and sail in a more direct course, are very destructive to birds,
game and poultry. Nevertheless, at least ten of the first class
are killed by farmers, poultrymen, and sportsmen to one of
the latter, because they are slower, more numerous and more
conspicuous, and therefore more readily seen and shot. It
should not be inferred from the above that hawks of the first
class never kill birds, game or poultry, but they are mostly too
slow to catch swift birds often. Nevertheless, any of them can
catch a young bird or a chicken. Some individual hawks of
the soaring species become very destructive to young poultry
at times or to young game on a preserve, but it is not difficult
for a good hunter who is also a good shot to follow such a bird
and kill it while it is eating its prey. The great horned owl
sometimes acquires the habit of coming to a game preserve at
night and taking birds. When this happens it must be stopped,
even if the pole trap has to be resorted to, for it is not always
possible to shoot a bird that comes after dark. Pole traps kept
set, however, will not only destroy useful hawks but will catch
and kill many useful insect-eating song birds. Pole traps should
be used mainly in the dead of winter, when they will be most
likely to destroy principally those creatures that are most harm-
ful to the game. -It is only the occasional skunk, mink or
weasel that becomes destructive in the poultry house or the
game pen, but it is useless to talk thus to gamekeepers or
poultrymen, most of whom would gladly shoot any predatory
bird or mammal at sight.

Gamekeepers exert themselves to destroy all natural enemies
of birds indiscriminately, and it must be admitted that such a
policy, coupled with attention to breeding, tends to increase
the stock of game on a preserve. Such a policy regarding
sheep would lead to the destruction of all dogs. No doubt it
would be effective in increasing the numbers of sheep, as both
the innocent and ‘the guilty would be destroyed, but it would
be better to save the innocent, and particularly the dogs known
to protect sheep.

51

Let us hope, then, that preserves will never become so nu-
merous in this country as to bring on, through too much destruc-
tion of so-called vermin, the evils that, at times, have attended
such a policy of extermination in other lands.

The Failure of Bounty Laws.

Laws offering a price on the heads of rapacious creatures
have been passed from time to time in many States because of
the belief that such statutes would be beneficial by procuring
the destruction of noxious species. In most cases they have
failed utterly to bring about the desired result, and, in so far
as they have been successful, have accomplished more harm
than good. Dr. T. S. Palmer asserts that it is safe to say
that $3,000,000 were expended on bounties in the United States
in the five years prior to 1896.'_ Probably most of this money
has been worse than wasted, and much of it never would have
been expended if the advice of competent biologists had been
heeded. County and State treasuries have been emptied to
keep the scalp hunter afield. Useful as well as noxious crea~
tures have been slaughtered in large numbers, but the benefits
to the taxpayer have been conspicuously absent, and lawless
hunters have been the chief beneficiaries. Most bounty laws
have been proposed and enacted with the ostensible purpose
of securing the extermination of the animals thus proscribed
on account of the mistaken idea that this would greatly benefit
the community by protecting game, birds and poultry. We
may grant that in settled regions the extirpation of the wolf,
puma and rattlesnake would be desirable, but the complete
destruction of birds of prey and the smaller predatory animals
would have precisely the opposite effect from that intended
and hoped for. In a recent letter to Mr. B. 8S. Bowdish of
Demarest, New Jersey, Professor H. A. Surface, State zodlo-
gist of Pennsylvania, writes as follows: —

It is to be presumed that the object in paying a bounty for the heads
of hawks, owls, weasels and foxes is to protect birds and game animals,
but it will not do this. Mice and rats are more serious enemies of the

1 Palmer, Tt §.: Extermination of Noxious Animals by Bounties, Yearbook, U.S. Dept. of
Agr., 1896, p. 59.

52

eggs and young of birds than most persons believe. Where these are abun-
dant, no ground-nesting birds will be found. Weasels and even foxes
feed chiefly on rodents such as mice and rats, and also rabbits. Only
occasionally do they find their way to the poultry yard.

Bounty laws never have exterminated any wide-ranging ani-
mal, and in most cases where the smaller species were concerned
bounties have not even reduced their numbers permanently.
On the Island of Bermuda, with an area of less than twenty
square miles, an attempt to exterminate the English sparrow
by bounties cost $2,500, and was abandoned as impracticable.
Similar efforts in several American States have caused the ex-
penditure of large sums of money without producing as much
reduction in the numbers of the sparrow as has followed a single
severe winter. If a standing price sufficiently large could be
offered for an animal throughout its entire range its extinction
might ensue because of continuous pérsecution everywhere, in
the same way that birds have been extirpated when followed
throughout their range by hunters working under the stimulus
of a continually rising market price, or as the fur seal may yet
be exterminated, despite the efforts of the United States govern-
ment to protect it; but local or State bounty laws, even if
effective within prescribed limits, do not reduce greatly the
numbers of a species throughout its range. When a bounty
law works effectively in any one State it soon gets to be so
expensive that its repeal becomes a necessity and then the
persecuted species again increases in numbers. Bounties alone
have never brought about the extermination of any species in
the United States, and they have never secured results com-
mensurate with the expenditure involved. Several States have
paid premiums on bears for many years without much decrease
in their numbers. If an animal as large as a bear can survive
under a bounty system, how can such a system be expected to
extirpate smaller animals? Iowa, Minnesota, South Dakota,
Washington and Montana have expended very large sums in
bounties on small rodents, but have made little impression on
the multitude of these creatures.

53

Bounty Laws DO NoT PROTECT Birps.

In my “Decrease of Birds” the following in substance ap-
pears: The main object of all bird legislation is to protect the
birds. This can be done by restricting both the number of
shooters and the time during which shooting is allowed.
Bounty laws have precisely the opposite effect. They encourage
boys, foreigners and unemployed persons to roam with guns in
their hands through the woods and fields at all seasons of the
year, and furnish an excuse for the lawbreaker. This is sure to
result in the destruction of game birds and insectivorous birds at
all seasons, to say nothing of the poultry and other property of
the farmers that, perforce, must suffer. Probably every State that
has offered bounties in recent years has had this experience.!

Bounty Laws DO NOT PROTECT THE FARMER.

The following extract from the letter from Professor Surface,
hereinbefore quoted in part, shows plainly how bounty laws
eventually result in injury to crops: —

History, which is yet vivid in the memories of most of us, has shown
the evils of the bounty system. In the 90’s Ohio passed a bounty law;
and as that was my native State, in which I was living at the time, I had an
opportunity to see the disastrous results. Mice and rats, which are the
chief food of such creatures, became so abundant, not only in buildings
around the farms but also all over the farm, that a large percentage of
the farmers’ crops was destroyed by them. I have seen many a clover
field with the roots of the clover plants gnawed down several inches by
mice. I found it not uncommon for every shock containing corn also to
be the abode of several mice of two or more species, and in every case
the loss of grain to amount to ‘several dollars per acre. This increase in
destructive vermin was so marked that the citizens themselves had to cry
aloud for the removal of the bounty law in order that the natural enemies
of the pests could increase.

Bounty Laws ENCOURAGE FRaAvD.
Bounty acts no doubt are urged by many persons who hon-
estly believe in their effectiveness, but usually the beneficiaries
of such laws are among the chief movers for them, and often

4 Special Report on the Decrease of Birds and its Causes, with Suggestions for Bird Protection,
fifty-second annual report, Mass. State Board of Agr., 1909, p. 527.

54

a large share of the money paid out by the State goes to com-
paratively few people and is collected largely through fraud and
deceit. In my “Decrease of Birds” this is alluded to in the
following words: — :

Bounty laws always put a premium upon dishonesty. Under the so-
called scalp act of 1885, in Pennsylvania, upwards of $2,000 were realized
for a buffalo hide and a mule skin in one county by a party of hunters.
These hides were cut up and ‘“‘fixed” to resemble the scalps or ears of
predatory animals. Whether the magistrates also were ‘‘fixed” is not
recorded. A red fox was slain in one of the mountainous districts and its
pelt cut into sixty-one parts, for which the hunter received $61. Bounties
were paid on the heads of domestic fowls, grouse, cuckoos, and even
English sparrows, which were supposed to have been palmed off on the
authorities as the heads of hawks and owls. Birds and mammals were
killed in other States and shipped into Pennsylvania, and large amounts
of money thus were fraudulently obtained. 1

This but repeats the history of local and State bounty laws
everywhere.

In Massachusetts we had for years a law which provided for
the payment of a bounty of $5 each for seal’s tails. Some of
the Passamaquoddy Indians shot a few seals in Maine and
manufactured, from their skins imitation seal’s tails enough to
take from the different towns in Massachusetts some $2,500 in
bounties. That resulted in the repeal of the bounty law.

Dr. George W. Field, former chairman of the Massachusetts
State Commission on Fisheries and Game, asserts that he re-
calls one instance where one town paid $1,800 in bounties
fraudulently obtained, and another where nearly a bushel of
crow’s heads was used in collecting bounties repeatedly in a
Massachusetts town. In Pennsylvania a single owl furnished
three heads on which premiums were paid. When bounties
on the same species have been offered in adjacent States pre-
miums have been collected in both States on the same identical
trophies.

The heads or other remains of the following mammals and
birds are given by Dr. Warren as having been presented in
different counties of Pennsylvania where bounties were paid on

1 See Warren, B. H.: Birds of Massachusetts, annual report, Mass. State Board of Agr., 1890,
p. 45.

55

most of them by magistrates or commissioners who either had
no zodlogical knowledge or were influenced by other considera-
tions than that of saving money for the Commonwealth: calf,
dog, jack rabbit, cat, squirrel, herring gull, turkey, vulture,
osprey, ruffed grouse, sharp-tailed grouse, horned grebe, whip-
poorwill, night hawk, shrike. Such heads or other remains
were presented, accepted and paid for with the understanding
that they were those of wolves, foxes, wild cats, minks, weasels,
hawks or owls. Bounties were paid not only on one head of
some of these species but on many. ‘The heads of grouse pre-
sented for bounty probably were trimmed from birds dressed
in the market.

On February 25, 1916, Dr. Joseph Kalbfus, secretary of the
Game Commission of Pennsylvania, gave at the More Game
Convention of the Michigan Wild Life Conservation Associa-
tion at Saginaw, Michigan, some experience with the Pennsyl-
vania commissioners in regard to bounty frauds. He said he
would not have believed there were so many men in Penn-
sylvania who would commit perjury for a dollar. One man
claimed to have killed 102 goshawks in four days in July. The
goshawk is a bird that is not found in Pennsylvania except
in autumn, winter or early spring. He also claimed to have
‘killed 347 weasels in two months. The man was convicted of
perjury and sent to jail. In one of the northern counties of
Pennsylvania tens of thousands of weasel skins were brought
in, some of them brought from Pennsylvania, some from Can-
ada, New York, Indiana, Ohio, etc., bought at 6 or 8 cents
apiece, and sold to the State of Pennsylvania for $2 each.
One boy was convicted for conspiring with a justice of the
peace to make out claims for $74. The boy did not bring in a
feather or a hair, but he got his money. Such frauds were
common. Many affidavits were made out in the names of
men who knew nothing of the matter. Certificates were raised
in amount from $2 to $22. These were raised by the claimants
or by some one in the offices of the county officials. Justices
of the peace simply assumed that men had killed certain ani-
mals, filled out papers, signed claimant’s bogus names and drew
the money. Frauds such as these have been perpetrated on
the State of Pennsylvania within the past two years.

56

In some States one county has required the presentation of
the head of an animal for the bounty while another exacted the
tail. As a consequence the hunters readily collected a fee from
each county. Every State offering bounties while surrounding
States did not has had to pay premiums on the heads of preda-
tory creatures from other States.

Such protection as is needed by birds, game and poultry
against their natural.enemies must and will be given without
the stimulus of bounty laws. Self-interest will teach the farmer,
poultryman and gamekeeper to destroy any animal that is
known to prey on his particular charge. The trapper will
keep down fur-bearing animals because of the increasing value
of their pelts.

Sufficient protection will be given to birds against their
natural enemies by the shooters themselves when they learn
what protection is needed. All gunners will shoot the cooper’s
and sharp-shinned hawks at sight when they know them and
know their character. They will also shoot cats, foxes, crows,
squirrels and all the enemies of birds indiscriminately, when-
ever they recognize them as enemies. Hence, so long as we
allow the shooting of game, the shooters are likely to keep the
enemies of birds within reasonable limits. Crows, foxes and
bird-hawks may increase in some cases, owing to their well-
known ability to take care of themselves, but the law does
not protect any of these creatures, and they may be kept in
subjection without bounty laws.

Some of my published observations regarding the operations
of special bounty laws follow: —

While the effect of bounty laws in general is bad, the practical operation
of laws directed at particular species is certainly vicious. We may regard
a bounty on the heads of cats as impracticable for obvious reasons, not the
least among which might be the encouragement of a new industry, —
the raising of kittens for the bounty. A bounty on cats, foxes, weasels
and skunks would encourage trapping, which is already exterminating
some of the smaller fur-bearing animals. The experience of States which
have placed bounties on the head of the English sparrow has not been
encouraging. These acts are said to have resulted in a slight decrease
of the sparrows, and the destruction of great numbers of native birds
killed and ignorantly offered for bounty. To put a bounty on the head
of the sparrow is practically equivalent to offering a bounty on all our
native sparrows, many of the warblers, the thrushes, wrens and a few

57

other species. Anything that at a distance looks like a sparrow would be
killed; and probably in most cases the bounty would be paid, unless a
competent naturalist could be appointed in each town or county seat to
pass on the heads.

If we offer a bounty on the crow, most of the native crows which do
the mischief probably will escape, and the bounty will be paid mainly on
birds that come from the north in winter. The difficulty of killing crows
in the summer prevents many being taken at that time. In the winter
most of the crows that summer here probably go farther south, their
places being taken by crows from farther north. It is at this time that
crows are most readily killed, either by baiting or at their roosts; and
therefore most of the crows offered for bounty would be those which never
do any injury here, while the guilty ones would escape.

A bounty on hawks or owls would work injury to the agricultural
interests. Hawks, with a few exceptions, are useful birds. Owls, most
of which are among the most useful of all birds, should be protected by
law, rather than proscribed. When in 1886 the people of Pennsylvania
became aware of the injurious effects of the “scalp act,” Dr. C. Hart
Merriam, then ornithologist and mammalogist of the United States De-
partment of Agriculture, his assistant, Dr. A. K. Fisher, and Dr. B. H.
Warren, examined over three hundred and fifty stomachs of the hawks
and owls killed under the act. Ninety-five per cent of the food materials
of these birds was found to consist, not of poultry and game, but of
“mice and other destructive mammals, grasshoppers and many injurious
beetles.” Dr. Merriam says, in his report for 1886: “By virtue of
this act about $90,000 has been paid in bounties during the year and a
half that has elapsed since the law went into effect. This represents the
destruction of at least 128,571 of the above-mentioned animals, most of
which were hawks and owls. Granting that five thousand chickens are
killed annually in Pennsylvania by hawks and owls, and that they are
worth 25 cents each (a liberal estimate, in view of the fact that a large
proportion of them are killed when very young), the total loss would be
$1,250, and the poultry killed in a year and a half would be worth $1,875.
Hence it appears that in the past eighteen months the State of Pennsyl-
vania has expended $90,000 to save its farmers a loss of $1,875. But this
estimate by no means represents the actual loss to the farmer and the
taxpayer of the State.’ Dr. Merriam then goes on to show the vast loss
that must result to the people of Pennsylvania, who, by killing these
hawks and owls, have saved the field mice and other harmful creatures
on which the birds otherwise would have preyed. The Legislature of
Pennsylvania appointed a State ornithologist, and repealed the scalp act.
We do not need a “scalp act” in Massachusetts.

The following from Dr. Palmer’s summary shows tersely the
principal objections to any system of premiums for the de-
struction of animals: —

58

Objections to the bounty system may be grouped under four main
heads: (a) expense, which is usually out of all proportion to the benefit
gained, and may be greater than the county or State can afford; (6) im-
possibility of maintaining bounties in all parts of an animal’s range for
any length of time; (c) impossibility of maintaining equal rates in all
States; (d) impossibility of preventing payments for animals imported
from other States, for counterfeit scalps or for animals raised especially for
the bounty. These objections have never been satisfactorily overcome,
and most laws have failed through one or another of these causes.’

CONCLUSION.

In recapitulating, it may be said that this bulletin shows
that (1) natural enemies of birds are necessary and desirable,
as they tend to maintain within proper bounds the numbers
of the species on which they prey; (2) organized attempts to
increase the numbers of birds over large areas by destroying
indiscriminately all natural enemies are undesirable; (3) under
certain circumstances enemies which have been able to adapt
themselves to man and his works and have become unduly
numerous may require reduction in numbers; (4) individuals
of useful species which may become particularly destructive
should be eliminated; (5) self-interest on the part of the people
most concerned eventually will bring about such reduction of
predatory animals as is needed without the stimulus of bounty
laws, which in most cases are pernicious and which if enacted at
all should be directed only against the larger predatory animals
or those which are dangerous to human life or exceedingly de-
structive to domestic animals or crops.

1 Palmer, T. S.: Extermination of Noxious Animals by Bounties, Yearbook, U.S. Dept. of
Agr., 1896, p. 68.

MANGMET BIRD OBSERVATORY