the return of the birds, and the early mornings are strangely silent where once they were filled
with the beauty of bird song. This sudden silencing of the song of birds, this obliteration of the
color and beauty and interest they lend to our world have come about swiftly, insidiously, and
unnoticed by those whose communities are as yet unaffected. From the town of Hinsdale,
Illinois, a housewife wrote in despair to one of the world’s leading ornithologists, Robert
Cushman Murphy, Curator Emeritus of Birds at the American Museum of Natural History.
Here in our village the elm trees have been sprayed for several years [she wrote in 1958]. When
we moved here six years ago, there was a wealth of bird life; I put up a feeder and had a steady
stream of cardinals, chickadees, downies and nuthatches all winter, and the cardinals and
chickadees brought their young ones in the summer. After several years of DDT spray, the town
is almost devoid of robins and starlings; chickadees have not been on my shelf for two years,
and this year the cardinals are gone too; the nesting population in the neighborhood seems to
consist of one dove pair and perhaps one catbird family.
It is hard to explain to the children that the birds have been killed off, when they have learned
in school that a Federal law protects the birds from killing or capture. ‘Will they ever come
back?’ they ask, and I do not have the answer. The elms are still dying, and so are the birds. Is
anything being done? Can anything be done? Can I do anything? A year after the federal
government had launched a massive spraying program against the fire ant, an Alabama woman
wrote: ‘Our place has been a veritable bird sanctuary for over half a century. Last July we all
remarked, “There are more birds than ever.” Then, suddenly, in the second week of August,
they all disappeared. I was accustomed to rising early to care for my favorite mare that had a
young filly. There was not a sound of the song of a bird. It was eerie, terrifying. What was man
doing to our perfect and beautiful world? Finally, five months later a blue jay appeared and a
wren.’ The autumn months to which she referred brought other somber reports from the deep
South, where in Mississippi, Louisiana, and Alabama the Field Notes published quarterly by the
National Audubon Society and the United States Fish and Wildlife Service noted the striking
phenomenon of ‘blank spots weirdly empty of virtually all bird life’. The Field Notes are a
compilation of the reports of seasoned observers who have spent many years afield in their
particular areas and have unparalleled knowledge of the normal bird life of the region. One
such observer reported that in driving about southern Mississippi that fall she saw ‘no land
birds at all for long distances’. Another in Baton Rouge reported that the contents of her
feeders had lain untouched ‘for weeks on end’, while fruiting shrubs in her yard, that ordinarily
would be stripped clean by that time, still were laden with berries. Still another reported that
his picture window, ‘which often used to frame a scene splashed with the red of 40 or 50
cardinals and crowded with other species, seldom permitted a view of as many as a bird or two
at a time.’ Professor Maurice Brooks of the University of West Virginia, an authority on the
birds of the Appalachian region, reported that the West Virginia bird population had undergone
‘an incredible reduction’. One story might serve as the tragic symbol of the fate of the birds—a
fate that has already overtaken some species, and that threatens all. It is the story of the robin,
the bird known to everyone. To millions of Americans, the season’s first robin means that the
grip of winter is broken. Its coming is an event reported in newspapers and told eagerly at the
breakfast table. And as the number of migrants grows and the first mists of green appear in the
woodlands, thousands of people listen for the first dawn chorus of the robins throbbing in the
early morning light. But now all is changed, and not even the return of the birds may be taken
for granted. The survival of the robin, and indeed of many other species as well, seems fatefully
linked with the American elm, a tree that is part of the history of thousands of towns from the
Atlantic to the Rockies, gracing their streets and their village squares and college campuses with
majestic archways of green. Now the elms are stricken with a disease that afflicts them
throughout their range, a disease so serious that many experts believe all efforts to save the
elms will in the end be futile. It would be tragic to lose the elms, but it would be doubly tragic if,
in vain efforts to save them, we plunge vast segments of our bird populations into the night of
extinction. Yet this is precisely what is threatened. The so-called Dutch elm disease entered the
United States from Europe about 1930 in elm burl logs imported for the veneer industry. It is a
fungus disease; the organism invades the water-conducting vessels of the tree, spreads by
spores carried by the flow of sap, and by its poisonous secretions as well as by mechanical
clogging causes the branches to wilt and the tree to die. The disease is spread from diseased to
healthy trees by elm bark beetles. The galleries which the insects have tunneled out under the
bark of dead trees become contaminated with spores of the invading fungus, and the spores
adhere to the insect body and are carried wherever the beetle flies. Efforts to control the
fungus disease of the elms have been directed largely toward control of the carrier insect. In
community after community, especially throughout the strongholds of the American elm, the
Midwest and New England, intensive spraying has become a routine procedure.
What this spraying could mean to bird life, and especially to the robin, was first made clear by
the work of two ornithologists at Michigan State University, Professor George Wallace and one
of his graduate students, John Mehner. When Mr. Mehner began work for the doctorate in
1954, he chose a research project that had to do with robin populations. This was quite by
chance, for at that time no one suspected that the robins were in danger. But even as he
undertook the work, events occurred that were to change its character and indeed to deprive
him of his material. Spraying for Dutch elm disease began in a small way on the university
campus in 1954. The following year the city of East Lansing (where the university is located)
joined in, spraying on the campus was expanded, and, with local programs for gypsy moth and
mosquito control also under way, the rain of chemicals increased to a downpour. During 1954,
the year of the first light spraying, all seemed well. The following spring the migrating robins
began to return to the campus as usual. Like the bluebells in Tomlinson’s haunting essay ‘The
Lost Wood’, they were ‘expecting no evil’ as they reoccupied their familiar territories. But soon
it became evident that something was wrong. Dead and dying robins began to appear in the
campus. Few birds were seen in their normal foraging activities or assembling in their usual
roosts. Few nests were built; few young appeared. The pattern was repeated with monotonous
regularity in succeeding springs. The sprayed area had become a lethal trap in which each wave
of migrating robins would be eliminated in about a week. Then new arrivals would come in,
only to add to the numbers of doomed birds seen on the campus in the agonized tremors that
precede death. ‘The campus is serving as a graveyard for most of the robins that attempt to
take up residence in the spring,’ said Dr. Wallace. But why? At first he suspected some disease
of the nervous system, but soon it became evident that ‘in spite of the assurances of the
insecticide people that their sprays were “harmless to birds” the robins were really dying of
insecticidal poisoning; they exhibited the well-known symptoms of loss of balance, followed by
tremors, convulsions, and death.’
Several facts suggested that the robins were being poisoned, not so much by direct contact
with the insecticides as indirectly, by eating earthworms. Campus earthworms had been fed
inadvertently to crayfish in a research project and all the crayfish had promptly died. A snake
kept in a laboratory cage had gone into violent tremors after being fed such worms. And
earthworms are the principal food of robins in the spring. A key piece in the jigsaw puzzle of the
doomed robins was soon to be supplied by Dr. Roy Barker of the Illinois Natural History Survey
at Urbana. Dr. Barker’s work, published in 1958, traced the intricate cycle of events by which
the robins’ fate is linked to the elm trees by way of the earthworms. The trees are sprayed in
the spring (usually at the rate of 2 to 5 pounds of DDT per 50-foot tree, which may be the
equivalent of as much as 23 pounds per acre where elms are numerous) and often again in July,
at about half this concentration. Powerful sprayers direct a stream of poison to all parts of the
tallest trees, killing directly not only the target organism, the bark beetle, but other insects,
including pollinating species and predatory spiders and beetles. The poison forms a tenacious
film over the leaves and bark. Rains do not wash it away. In the autumn the leaves fall to the
ground, accumulate in sodden layers, and begin the slow process of becoming one with the soil.
In this they are aided by the toil of the earthworms, who feed in the leaf litter, for elm leaves
are among their favorite foods. In feeding on the leaves the worms also swallow the insecticide,
accumulating and concentrating it in their bodies. Dr. Barker found deposits of DDT throughout
the digestive tracts of the worms, their blood vessels, nerves, and body wall. Undoubtedly
some of the earthworms themselves succumb, but others survive to become ‘biological
magnifiers’ of the poison. In the spring the robins return to provide another link in the cycle. As
few as 11 large earthworms can transfer a lethal dose of DDT to a robin. And 11 worms form a
small part of a day’s rations to a bird that eats 10 to 12 earthworms in as many minutes.
Not all robins receive a lethal dose, but another consequence may lead to the extinction of
their kind as surely as fatal poisoning. The shadow of sterility lies over all the bird studies and
indeed lengthens to include all living things within its potential range. There are now only two
or three dozen robins to be found each spring on the entire 185-acre campus of Michigan State
University, compared with a conservatively estimated 370 adults in this area before spraying. In
1954 every robin nest under observation by Mehner produced young. Toward the end of June,
1957, when at least 370 young birds (the normal replacement of the adult population) would
have been foraging over the campus in the years before spraying began, Mehner could find only
one young robin. A year later Dr. Wallace was to report: ‘At no time during the spring or
summer [of 1958] did I see a fledgling robin anywhere on the main campus, and so far I have
failed to find anyone else who has seen one there.’
Part of this failure to produce young is due, of course, to the fact that one or more of a pair of
robins dies before the nesting cycle is completed. But Wallace has significant records which
point to something more sinister—the actual destruction of the birds’ capacity to reproduce.
He has, for example, ‘records of robins and other birds building nests but laying no eggs, and
others laying eggs and incubating them but not hatching them. We have one record of a robin
that sat on its eggs faithfully for 21 days and they did not hatch. The normal incubation period
is 13 days...Our analyses are showing high concentrations of DDT in the testes and ovaries of
breeding birds,’ he told a congressional committee in 1960. ‘Ten males had amounts ranging
from 30 to 109 parts per million in the testes, and two females had 151 and 211 parts per
million respectively in the egg follicles in their ovaries.’ Soon studies in other areas began to
develop findings equally dismal. Professor Joseph Hickey and his students at the University of
Wisconsin, after careful comparative studies of sprayed and unsprayed areas, reported the
robin mortality to be at least 86 to 88 per cent. The Cranbrook Institute of Science at Bloomfield
Hills, Michigan, in an effort to assess the extent of bird loss caused by the spraying of the elms,
asked in 1956 that all birds thought to be victims of DDT poisoning be turned in to the institute
for examination. The request had a response beyond all expectations. Within a few weeks the
deep-freeze facilities of the institute were taxed to capacity, so that other specimens had to be
refused. By 1959 a thousand poisoned birds from this single community had been turned in or
reported. Although the robin was the chief victim (one woman calling the institute reported 12
robins lying dead on her lawn as she spoke), 63 different species were included among the
specimens examined at the institute. The robins, then, are only one part of the chain of
devastation linked to the spraying of the elms, even as the elm program is only one of the
multitudinous spray programs that cover our land with poisons. Heavy mortality has occurred
among about 90 species of birds, including those most familiar to suburbanites and amateur
naturalists. The populations of nesting birds in general have declined as much as 90 per cent in
some of the sprayed towns. As we shall see, all the various types of birds are affected—ground
feeders, treetop feeders, bark feeders, predators. It is only reasonable to suppose that all birds
and mammals heavily dependent on earthworms or other soil organisms for food are
threatened by the robins’ fate. Some 45 species of birds include earthworms in their diet.
Among them is the woodcock, a species that winters in southern areas recently heavily sprayed
with heptachlor. Two significant discoveries have now been made about the woodcock.
Production of young birds on the New Brunswick breeding grounds is definitely reduced, and
adult birds that have been analyzed contain large residues of DDT and heptachlor. Already
there are disturbing records of heavy mortality among more than 20 other species of ground-
feeding birds whose food—worms, ants, grubs, or other soil organisms—has been poisoned.
These include three of the thrushes whose songs are among the most exquisite of bird voices,
the olive-backed, the wood, and the hermit. And the sparrows that flit through the shrubby
understory of the woodlands and forage with rustling sounds amid the fallen leaves—the song
sparrow and the white-throat—these, too, have been found among the victims of the elm
sprays. Mammals, also, may easily be involved in the cycle, directly or indirectly. Earthworms
are important among the various foods of the raccoon, and are eaten in the spring and fall by
opossums. Such subterranean tunnelers as shrews and moles capture them in numbers, and
then perhaps pass on the poison to predators such as screech owls and barn owls.
Several dying screech owls were picked up in Wisconsin following heavy rains in spring, perhaps
poisoned by feeding on earthworms. Hawks and owls have been found in convulsions—great
horned owls, screech owls, red-shouldered hawks, sparrow hawks, marsh hawks. These may be
cases of secondary poisoning, caused by eating birds or mice that have accumulated
insecticides in their livers or other organs. Nor is it only the creatures that forage on the ground
or those who prey on them that are endangered by the foliar spraying of the elms. All of the
treetop feeders, the birds that glean their insect food from the leaves, have disappeared from
heavily sprayed areas, among them those woodland sprites the kinglets, both ruby-crowned
and golden-crowned, the tiny gnatcatchers, and many of the warblers, whose migrating hordes
flow through the trees in spring in a multicolored tide of life. In 1956, a late spring delayed
spraying so that it coincided with the arrival of an exceptionally heavy wave of warbler
migration. Nearly all species of warblers present in the area were represented in the heavy kill
that followed. In Whitefish Bay, Wisconsin, at least a thousand myrtle warblers could be seen in
migration during former years; in 1958, after the spraying of the elms, observers could find only
two. So, with additions from other communities, the list grows, and the warblers killed by the
spray include those that most charm and fascinate all who are aware of them: the black-and-
white, the yellow, the magnolia, and the Cape May; the ovenbird, whose call throbs in the
Maytime woods; the Blackburnian, whose wings are touched with flame; the chestnut-sided,
the Canadian, and the black-throated green. These treetop feeders are affected either directly
by eating poisoned insects or indirectly by a shortage of food.
The loss of food has also struck hard at the swallows that cruise the skies, straining out the
aerial insects as herring strain the plankton of the sea. A Wisconsin naturalist reported:
‘Swallows have been hard hit. Everyone complains of how few they have compared to four or
five years ago. Our sky overhead was full of them only four years ago. Now we seldom see
any...This could be both lack of insects because of spray, or poisoned insects.’ Of other birds
this same observer wrote: ‘Another striking loss is the phoebe. Flycatchers are scarce
everywhere but the early hardy common phoebe is no more. I’ve seen one this spring and only
one last spring. Other birders in Wisconsin make the same complaint. I have had five or six pair
of cardinals in the past, none now. Wrens, robins, catbirds and screech owls have nested each
year in our garden. There are none now. Summer mornings are without bird song. Only pest
birds, pigeons, starlings and English sparrows remain. It is tragic and I can’t bear it.’
The dormant sprays applied to the elms in the fall, sending the poison into every little crevice in
the bark, are probably responsible for the severe reduction observed in the number of
chickadees, nuthatches, titmice, woodpeckers, and brown creepers. During the winter of 1957-
58, Dr. Wallace saw no chickadees or nuthatches at his home feeding station for the first time
in many years. Three nuthatches he found later provided a sorry little step-by-step lesson in
cause and effect: one was feeding on an elm, another was found dying of typical DDT
symptoms, the third was dead. The dying nuthatch was later found to have 226 parts per
million of DDT in its tissues. The feeding habits of all these birds not only make them especially
vulnerable to insect sprays but also make their loss a deplorable one for economic as well as
less tangible reasons. The summer food of the white-breasted nuthatch and the brown creeper,
for example, includes the eggs, larvae, and adults of a very large number of insects injurious to
trees. About three quarters of the food of the chickadee is animal, including all stages of the life
cycle of many insects. The chickadee’s method of feeding is described in Bent’s monumental
Life Histories of North American birds: ‘As the flock moves along each bird examines minutely
bark, twigs, and branches, searching for tiny bits of food (spiders’ eggs, cocoons, or other
dormant insect life).’ Various scientific studies have established the critical role of birds in insect
control in various situations. Thus, woodpeckers are the primary control of the Engelmann
spruce beetle, reducing its populations from 45 to 98 per cent and are important in the control
of the codling moth in apple orchards. Chickadees and other winter-resident birds can protect
orchards against the cankerworm.
But what happens in nature is not allowed to happen in the modern, chemical-drenched world,
where spraying destroys not only the insects but their principal enemy, the birds. When later
there is a resurgence of the insect population, as almost always happens, the birds are not
there to keep their numbers in check. As the Curator of Birds at the Milwaukee Public Museum,
Owen J. Gromme, wrote to the Milwaukee Journal: ‘The greatest enemy of insect life is other
predatory insects, birds, and some small mammals, but DDT kills indiscriminately, including
nature’s own safeguards or policemen... In the name of progress are we to become victims of
our own diabolical means of insect control to provide temporary comfort, only to lose out to
destroying insects later on? By what means will we control new pests, which will attack
remaining tree species after the elms are gone, when nature’s safeguards (the birds) have been
wiped out by poison?’
Mr. Gromme reported that calls and letters about dead and dying birds had been increasing
steadily during the years since spraying began in Wisconsin. Questioning always revealed that
spraying or fogging had been done in the area where the birds were dying.
Mr. Gromme’s experience has been shared by ornithologists and conservationists at most of
the research centers of the Midwest such as the Cranbrook Institute in Michigan, the Illinois
Natural History Survey, and the University of Wisconsin. A glance at the Letters-from-Readers
column of newspapers almost anywhere that spraying is being done makes clear the fact that
citizens are not only becoming aroused and indignant but that often they show a keener
understanding of the dangers and inconsistencies of spraying than do the officials who order it
done. ‘I am dreading the days to come soon now when many beautiful birds will be dying in our
back yard,’ wrote a Milwaukee woman. ‘This is a pitiful, heartbreaking experience... It is,
moreover, frustrating and exasperating, for it evidently does not serve the purpose this
slaughter was intended to serve... Taking a long look, can you save trees without also saving
birds? Do they not, in the economy of nature, save each other? Isn’t it possible to help the
balance of nature without destroying it?’ The idea that the elms, majestic shade trees though
they are, are not ‘sacred cows’ and do not justify an ‘open end’ campaign of destruction against
all other forms of life is expressed in other letters. ‘I have always loved our elm trees which
seemed like trademarks on our landscape,’ wrote another Wisconsin woman. ‘But there are
many kinds of trees...We must save our birds, too. Can anyone imagine anything so cheerless
and dreary as a springtime without a robin’s song?’ To the public the choice may easily appear
to be one of stark black-or-white simplicity: Shall we have birds or shall we have elms? But it is
not as simple as that, and by one of the ironies that abound throughout the field of chemical
control we may very well end by having neither if we continue on our present, well-traveled
road. Spraying is killing the birds but it is not saving the elms. The illusion that salvation of the
elms lies at the end of a spray nozzle is a dangerous will-o’- the-wisp that is leading one
community after another into a morass of heavy expenditures, without producing lasting
results. Greenwich, Connecticut sprayed regularly for ten years. Then a drought year brought
conditions especially favorable to the beetle and the mortality of elms went up 1000 per cent.
In Urbana, Illinois, where the University of Illinois is located, Dutch elm disease first appeared in
1951. Spraying was undertaken in 1953. By 1959, in spite of six years’ spraying, the university
campus had lost 86 per cent of its elms, half of them victims of Dutch elm disease. In Toledo,
Ohio, a similar experience caused the Superintendent of Forestry, Joseph A. Sweeney, to take a
realistic look at the results of spraying. Spraying was begun there in 1953 and continued
through 1959. Meanwhile, however, Mr. Sweeney had noticed that a city-wide infestation of
the cottony maple scale was worse after the spraying recommended by ‘the books and the
authorities’ than it had been before. He decided to review the results of spraying for Dutch elm
disease for himself. His findings shocked him. In the city of Toledo, he found, ‘the only areas
under any control were the areas where we used some promptness in removing the diseased or
brood trees. Where we depended on spraying the disease was out of control. In the country
where nothing has been done the disease has not spread as fast as it has in the city. This
indicates that spraying destroys any natural enemies. ‘We are abandoning spraying for the
Dutch elm disease. This has brought me into conflict with the people who back any
recommendations by the United States Department of Agriculture but I have the facts and will
stick with them.’ It is difficult to understand why these midwestern towns, to which the elm
disease spread only rather recently, have so unquestioningly embarked on ambitious and
expensive spraying programs, apparently without waiting to inquire into the experience of
other areas that have had longer acquaintance with the problem. New York State, for example,
has certainly had the longest history of continuous experience with Dutch elm disease, for it
was via the Port of New York that diseased elm wood is thought to have entered the United
States about 1930. And New York State today has a most impressive record of containing and
suppressing the disease. Yet it has not relied upon spraying. In fact, its agricultural extension
service does not recommend spraying as a community method of control.
How, then, has New York achieved its fine record? From the early years of the battle for the
elms to the present time, it has relied upon rigorous sanitation, or the prompt removal and
destruction of all diseased or infected wood. In the beginning some of the results were
disappointing, but this was because it was not at first understood that not only diseased trees
but all elm wood in which the beetles might breed must be destroyed. Infected elm wood, after
being cut and stored for firewood, will release a crop of fungus-carrying beetles unless burned
before spring. It is the adult beetles, emerging from hibernation to feed in late April and May,
that transmit Dutch elm disease. New York entomologists have learned by experience what
kinds of beetle-breeding material have real importance in the spread of the disease. By
concentrating on this dangerous material, it has been possible not only to get good results, but
to keep the cost of the sanitation program within reasonable limits. By 1950 the incidence of
Dutch elm disease in New York City had been reduced to of 1 per cent of the city’s 55,000 elms.
A sanitation program was launched in Westchester County in 1942.
During the next 14 years the average annual loss of elms was only of 1 per cent a year. Buffalo,
with 185,000 elms, has an excellent record of containing the disease by sanitation, with recent
annual losses amounting to only of 1 per cent. In other words, at this rate of loss it would take
about 300 years to eliminate Buffalo’s elms. What has happened in Syracuse is especially
impressive. There no effective program was in operation before 1957. Between 1951 and 1956
Syracuse lost nearly 3000 elms. Then, under the direction of Howard C. Miller of the New York
State University College of Forestry, an intensive drive was made to remove all diseased elm
trees and all possible sources of beetle-breeding elm wood. The rate of loss is now well below 1
per cent a year. The economy of the sanitation method is stressed by New York experts in
Dutch elm disease control. ‘In most cases the actual expense is small compared with the
probable saving,’ says J. G. Matthysse of the New York State College of Agriculture. ‘If it is a
case of a dead or broken limb, the limb would have to be removed eventually, as a precaution
against possible property damage or personal injury. If it is a fuel-wood pile, the wood can be
used before spring, the bark can be peeled from the wood, or the wood can be stored in a dry
place. In the case of dying or dead elm trees, the expense of prompt removal to prevent Dutch
elm disease spread is usually no greater than would be necessary later, for most dead trees in
urban regions must be removed eventually.’ The situation with regard to Dutch elm disease is
therefore not entirely hopeless provided informed and intelligent measures are taken. While it
cannot be eradicated by any means now known, once it has become established in a
community, it can be suppressed and contained within reasonable bounds by sanitation, and
without the use of methods that are not only futile but involve tragic destruction of bird life.
Other possibilities lie within the field of forest genetics, where experiments offer hope of
developing a hybrid elm resistant to Dutch elm disease. The European elm is highly resistant,
and many of them have been planted in Washington, D.C. Even during a period when a high
percentage of the city’s elms were affected, no cases of Dutch elm disease were found among
these trees. Replanting through an immediate tree nursery and forestry program is being urged
in communities that are losing large numbers of elms. This is important, and although such
programs might well include the resistant European elms, they should aim at a variety of
species so that no future epidemic could deprive a community of its trees. The key to a healthy
plant or animal community lies in what the British ecologist Charles Elton calls ‘the conservation
of variety’. What is happening now is in large part a result of the biological unsophistication of
past generations. Even a generation ago no one knew that to fill large areas with a single
species of tree was to invite disaster. And so whole towns lined their streets and dotted their
parks with elms, and today the elms die and so do the birds. . . .
Like the robin, another American bird seems to be on the verge of extinction. This is the
national symbol, the eagle. Its populations have dwindled alarmingly within the past decade.
The facts suggest that something is at work in the eagle’s environment which has virtually
destroyed its ability to reproduce. What this may be is not yet definitely known, but there is
some evidence that insecticides are responsible.
The most intensively studied eagles in North America have been those nesting along a stretch
of coast from Tampa to Fort Myers on the western coast of Florida. There a retired banker from
Winnipeg, Charles Broley, achieved ornithological fame by banding more than 1,000 young bald
eagles during the years 1939-49. (Only 166 eagles had been banded in all the earlier history of
birdbanding.) Mr. Broley banded eagles as young birds during the winter months before they
had left their nests. Later recoveries of banded birds showed that these Florida-born eagles
range northward along the coast into Canada as far as Prince Edward Island, although they had
previously been considered nonmigratory. In the fall they return to the South, their migration
being observed at such famous vantage points as Hawk Mountain in eastern Pennsylvania.
During the early years of his banding, Mr. Broley used to find 125 active nests a year on the
stretch of coast he had chosen for his work. The number of young banded each year was about
150. In 1947 the production of young birds began to decline. Some nests contained no eggs;
others contained eggs that failed to hatch. Between 1952 and 1957, about 80 per cent of the
nests failed to produce young. In the last year of this period only 43 nests were occupied. Seven
of them produced young (8 eaglets); 23 contained eggs that failed to hatch; 13 were used
merely as feeding stations by adult eagles and contained no eggs. In 1958 Mr. Broley ranged
over 100 miles of coast before finding and banding one eaglet. Adult eagles, which had been
seen at 43 nests in 1957, were so scarce that he observed them at only 10 nests. Although Mr.
Broley’s death in 1959 terminated this valuable series of uninterrupted observations, reports by
the Florida Audubon Society, as well as from New Jersey and Pennsylvania, confirm the trend
that may well make it necessary for us to find a new national emblem. The reports of Maurice
Broun, curator of the Hawk Mountain Sanctuary, are especially significant. Hawk Mountain is a
picturesque mountaintop in southeastern Pennsylvania, where the easternmost ridges of the
Appalachians form a last barrier to the westerly winds before dropping away toward the coastal
plain. Winds striking the mountains are deflected upward so that on many autumn days there is
a continuous updraft on which the broad-winged hawks and eagles ride without effort, covering
many miles of their southward migration in a day. At Hawk Mountain the ridges converge and
so do the aerial highways. The result is that from a widespread territory to the north birds pass
through this traffic bottleneck. In his more than a score of years as custodian of the sanctuary
there, Maurice Broun has observed and actually tabulated more hawks and eagles than any
other American. The peak of the bald eagle migration comes in late August and early
September. These are assumed to be Florida birds, returning to home territory after a summer
in the North. (Later in the fall and early winter a few larger eagles drift through. These are
thought to belong to a northern race, bound for an unknown wintering ground.) During the first
years after the sanctuary was established, from 1935 to 1939, 40 per cent of the eagles
observed were yearlings, easily identified by their uniformly dark plumage. But in recent years
these immature birds have become a rarity. Between 1955 and 1959, they made up only 20 per
cent of the total count, and in one year (1957) there was only one young eagle for every 32
adults. Observations at Hawk Mountain are in line with findings elsewhere. One such report
comes from Elton Fawks, an official of the Natural Resources Council of Illinois. Eagles—
probably northern nesters—winter along the Mississippi and Illinois Rivers. In 1958 Mr. Fawks
reported that a recent count of 59 eagles had included only one immature bird. Similar
indications of the dying out of the race come from the world’s only sanctuary for eagles alone,
Mount Johnson Island in the Susquehanna River. The island, although only 8 miles above
Conowingo Dam and about half a mile out from the Lancaster County shore, retains its
primitive wildness. Since 1934 its single eagle nest has been under observation by Professor
Herbert H. Beck, an ornithologist of Lancaster and custodian of the sanctuary. Between 1935
and 1947 use of the nest was regular and uniformly successful. Since 1947, although the adults
have occupied the nest and there is evidence of egg laying, no young eagles have been
produced. On Mount Johnson Island as well as in Florida, then, the same situation prevails—
there is some occupancy of nests by adults, some production of eggs, but few or no young
birds. In seeking an explanation, only one appears to fit all the facts. This is that the
reproductive capacity of the birds has been so lowered by some environmental agent that
there are now almost no annual additions of young to maintain the race.
Exactly this sort of situation has been produced artificially in other birds by various
experimenters, notably Dr. James DeWitt of the United States Fish and Wildlife Service. Dr.
DeWitt’s now classic experiments on the effect of a series of insecticides on quail and
pheasants have established the fact that exposure to DDT or related chemicals, even when
doing no observable harm to the parent birds, may seriously affect reproduction. The way the
effect is exerted may vary, but the end result is always the same. For example, quail into whose
diet DDT was introduced throughout the breeding season survived and even produced normal
numbers of fertile eggs. But few of the eggs hatched. ‘Many embryos appeared to develop
normally during the early stages of incubation, but died during the hatching period,’ Dr. DeWitt
said. Of those that did hatch, more than half died within 5 days. In other tests in which both
pheasants and quail were the subjects, the adults produced no eggs whatever if they had been
fed insecticide-contaminated diets throughout the year. And at the University of California, Dr.
Robert Rudd and Dr. Richard Genelly reported similar findings. When pheasants received
dieldrin in their diets, ‘egg production was markedly lowered and chick survival was poor.’
According to these authors, the delayed but lethal effect on the young birds follows from
storage of dieldrin in the yolk of the egg, from which it is gradually assimilated during
incubation and after hatching. This suggestion is strongly supported by recent studies by Dr.
Wallace and a graduate student, Richard F. Bernard, who found high concentrations of DDT in
robins on the Michigan State University campus. They found the poison in all of the testes of
male robins examined, in developing egg follicles, in the ovaries of females, in completed but
unlaid eggs, in the oviducts, in unhatched eggs from deserted nests, in embryos within the eggs,
and in a newly hatched, dead nestling. These important studies establish the fact that the
insecticidal poison affects a generation once removed from initial contact with it. Storage of
poison in the egg, in the yolk material that nourishes the developing embryo, is a virtual death
warrant and explains why so many of DeWitt’s birds died in the egg or a few days after
hatching.
Laboratory application of these studies to eagles presents difficulties that are nearly
insuperable, but field studies are now under way in Florida, New Jersey, and elsewhere in the
hope of acquiring definite evidence as to what has caused the apparent sterility of much of the
eagle population. Meanwhile, the available circumstantial evidence points to insecticides. In
localities where fish are abundant they make up a large part of the eagle’s diet (about 65 per
cent in Alaska; about 52 per cent in the Chesapeake Bay area). Almost unquestionably the
eagles so long studied by Mr. Broley were predominantly fish eaters. Since 1945 this particular
coastal area has been subjected to repeated sprayings with DDT dissolved in fuel oil. The
principal target of the aerial spraying was the salt-marsh mosquito, which inhabits the marshes
and coastal areas that are typical foraging areas for the eagles. Fishes and crabs were killed in
enormous numbers. Laboratory analyses of their tissues revealed high concentrations of DDT—
as much as 46 parts per million. Like the grebes of Clear Lake, which accumulated heavy
concentrations of insecticide residues from eating the fish of the lake, the eagles have almost
certainly been storing up the DDT in the tissues of their bodies. And like the grebes, the
pheasants, the quail, and the robins, they are less and less able to produce young and to
preserve the continuity of their race. . . .
From all over the world come echoes of the peril that faces birds in our modern world. The
reports differ in detail, but always repeat the theme of death to wildlife in the wake of
pesticides. Such are the stories of hundreds of small birds and partridges dying in France after
vine stumps were treated with an arsenic-containing herbicide, or of partridge shoots in
Belgium, once famous for the numbers of their birds, denuded of partridges after the spraying
of nearby farmlands. In England the major problem seems to be a specialized one, linked with
the growing practice of treating seed with insecticides before sowing. Seed treatment is not a
wholly new thing, but in earlier years the chemicals principally used were fungicides. No effects
on birds seem to have been noticed. Then about 1956 there was a change to dual-purpose
treatment; in addition to a fungicide, dieldrin, aldrin, or heptachlor was added to combat soil
insects. Thereupon the situation changed for the worse.
In the spring of 1960 a deluge of reports of dead birds reached British wildlife authorities,
including the British Trust for Ornithology, the Royal Society for the Protection of Birds, and the
Game Birds Association. ‘The place is like a battlefield,’ a landowner in Norfolk wrote. ‘My
keeper has found innumerable corpses, including masses of small birds— Chaffinches,
Greenfinches, Linnets, Hedge Sparrows, also House Sparrows...the destruction of wild life is
quite pitiful.’ A gamekeeper wrote: ‘My Partridges have been wiped out with the dressed corn,
also some Pheasants and all other birds, hundreds of birds have been killed... As a lifelong
gamekeeper it has been a distressing experience for me. It is bad to see pairs of Partridges that
have died together.’ In a joint report, the British Trust for Ornithology and the Royal Society for
the Protection of Birds described some 67 kills of birds—a far from complete listing of the
destruction that took place in the spring of 1960. Of these 67, 59 were caused by seed
dressings, 8 by toxic sprays. A new wave of poisoning set in the following year. The death of 600
birds on a single estate in Norfolk was reported to the House of Lords, and 100 pheasants died
on a farm in North Essex. It soon became evident that more counties were involved than in
1960 (34 compared with 23). Lincolnshire, heavily agricultural, seemed to have suffered most,
with reports of 10,000 birds dead. But destruction involved all of agricultural England, from
Angus in the north to Cornwall in the south, from Anglesey in the west to Norfolk in the east.
In the spring of 1961 concern reached such a peak that a special committee of the House of
Commons made an investigation of the matter, taking testimony from farmers, landowners,
and representatives of the Ministry of Agriculture and of various governmental and non-
governmental agencies concerned with wildlife. ‘Pigeons are suddenly dropping out of the sky
dead,’ said one witness. ‘You can drive a hundred or two hundred miles outside London and not
see a single kestrel,’ reported another. ‘There has been no parallel in the present century, or at
any time so far as I am aware, [this is] the biggest risk to wildlife and game that ever occurred in
the country,’ officials of the Nature Conservancy testified.
Facilities for chemical analysis of the victims were most inadequate to the task, with only two
chemists in the country able to make the tests (one the government chemist, the other in the
employ of the Royal Society for the Protection of Birds). Witnesses described huge bonfires on
which the bodies of the birds were burned. But efforts were made to have carcasses collected
for examination, and of the birds analyzed, all but one contained pesticide residues. The single
exception was a snipe, which is not a seed-eating bird. Along with the birds, foxes also may
have been affected, probably indirectly by eating poisoned mice or birds. England, plagued by
rabbits, sorely needs the fox as a predator. But between November 1959 and April 1960 at least
1300 foxes died. Deaths were heaviest in the same counties from which sparrow hawks,
kestrels, and other birds of prey virtually disappeared, suggesting that the poison was spreading
through the food chain, reaching out from the seed eaters to the furred and feathered
carnivores. The actions of the moribund foxes were those of animals poisoned by chlorinated
hydrocarbon insecticides. They were seen wandering in circles, dazed and half blind, before
dying in convulsions.
The hearings convinced the committee that the threat to wildlife was ‘most alarming’; it
accordingly recommended to the House of Commons that ‘the Minister of Agriculture and the
Secretary of State for Scotland should secure the immediate prohibition for the use as seed
dressings of compounds containing dieldrin, aldrin, or heptachlor, or chemicals of comparable
toxicity.’ The committee also recommended more adequate controls to ensure that chemicals
were adequately tested under field as well as laboratory conditions before being put on the
market. This, it is worth emphasizing, is one of the great blank spots in pesticide research
everywhere. Manufacturers’ tests on the common laboratory animals—rats, dogs, guinea
pigs—include no wild species, no birds as a rule, no fishes, and are conducted under controlled
and artificial conditions. Their application to wildlife in the field is anything but precise. England
is by no means alone in its problem of protecting birds from treated seeds. Here in the United
States the problem has been most troublesome in the rice-growing areas of California and the
South. For a number of years California rice growers have been treating seed with DDT as
protection against tadpole shrimp and scavenger beetles which sometimes damage seedling
rice. California sportsmen have enjoyed excellent hunting because of the concentrations of
waterfowl and pheasants in the rice fields. But for the past decade persistent reports of bird
losses, especially among pheasants, ducks, and blackbirds, have come from the rice-growing
counties. ‘Pheasant sickness’ became a well-known phenomenon: birds ‘seek water, become
paralyzed, and are found on the ditch banks and rice checks quivering,’ according to one
observer. The ‘sickness’ comes in the spring, at the time the rice fields are seeded. The
concentration of DDT used is many times the amount that will kill an adult pheasant.
The passage of a few years and the development of even more poisonous insecticides served to
increase the hazard from treated seed. Aldrin, which is 100 times as toxic as DDT to pheasants,
is now widely used as a seed coating. In the rice fields of eastern Texas, this practice has
seriously reduced the populations of the famous tree duck, a tawny-colored, gooselike duck of
the Gulf Coast. Indeed, there is some reason to think that the rice growers, having found a way
to reduce the populations of blackbirds, are using the insecticide for a dual purpose, with
disastrous effects on several bird species of the rice fields. As the habit of killing grows—the
resort to ‘eradicating’ any creature that may annoy or inconvenience us—birds are more and
more finding themselves a direct target of poisons rather than an incidental one. There is a
growing trend toward aerial applications of such deadly poisons as parathion to ‘control’
concentrations of birds distasteful to farmers. The Fish and Wildlife Service has found it
necessary to express serious concern over this trend, pointing out that ‘parathion treated areas
constitute a potential hazard to humans, domestic animals, and wildlife.’ In southern Indiana,
for example, a group of farmers went together in the summer of 1959 to engage a spray plane
to treat an area of river bottomland with parathion. The area was a favored roosting site for
thousands of blackbirds that were feeding in nearby corn fields. The problem could have been
solved easily by a slight change in agricultural practice shift to a variety of corn with deep-set
ears not accessible to the birds—but the farmers had been persuaded of the merits of killing by
poison, and so they sent in the planes on their mission of death.
The results probably gratified the farmers, for the casualty list included some 65,000 red-
winged blackbirds and starlings. What other wildlife deaths may have gone unnoticed and
unrecorded is not known. Parathion is not a specific for blackbirds: it is a universal killer. But
such rabbits or raccoons or opossums as may have roamed those bottomlands and perhaps
never visited the farmers’ cornfields were doomed by a judge and jury who neither knew of
their existence nor cared. And what of human beings? In California orchards sprayed with this
same parathion, workers handling foliage that had been treated a month earlier collapsed and
went into shock, and escaped death only through skilled medical attention.
Does Indiana still raise any boys who roam through woods or fields and might even explore the
margins of a river? If so, who guarded the poisoned area to keep out any who might wander in,
in misguided search for unspoiled nature? Who kept vigilant watch to tell the innocent stroller
that the fields he was about to enter were deadly—all their vegetation coated with a lethal
film? Yet at so fearful a risk the farmers, with none to hinder them, waged their needless war
on blackbirds. In each of these situations, one turns away to ponder the question: Who has
made the decision that sets in motion these chains of poisonings, this ever-widening wave of
death that spreads out, like ripples when a pebble is dropped into a still pond? Who has placed
in one pan of the scales the leaves that might have been eaten by the beetles and in the other
the pitiful heaps of many-hued feathers, the lifeless remains of the birds that fell before the
unselective bludgeon of insecticidal poisons? Who has decided —who has the right to decide—
for the countless legions of people who were not consulted that the supreme value is a world
without insects, even though it be also a sterile world ungraced by the curving wing of a bird in
flight? The decision is that of the authoritarian temporarily entrusted with power; he has made
it during a moment of inattention by millions to whom beauty and the ordered world of nature
still have a meaning that is deep and imperative.
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