August
2005
Invaders
or Victims?
By Monica Engebretson
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Glossy Starling |
It seems as if you hear them everywhere you turn: heated
debates about immigration and borders, about who ‘belongs’ and
who is an unwanted ‘intruder.’ For a nation founded—or ‘invaded’ depending
on who is speaking—by immigrants, and claims to still be a land
of opportunity and hope for the less fortunate of the world, the U.S.
has a profoundly ambivalent, contradictory, and at times, openly hostile
view of immigrants.
Ambivalent, contradictory, and hostile are also apt descriptions of our relationship
with nonhuman, non-native animals. We can’t seem to decide if they are
saviors or scourges. For example, in the late 1800s, the American Acclimation
Society set out to deliberately introduce European plants and animals into the
U.S.—in part, to make Europeans feel more at home. While the majority of
introduced birds perished, the European starling, released in New York’s
Central Park in 1890 and again in 1891, quickly became one of the most abundant
birds in North America.
Starlings are not the only ‘foreigners’ to establish themselves here.
At least 74 free-living exotic parrot species are known to exist in North America.
While most escaped or released parrots succumb to the elements, starvation, or
predation, certain species in certain climates have shown that they are able
to survive in the urban jungles of the U.S.
One of the most abundant free-living parrot species in the U.S. is the monk or
quaker parakeet. Thousands of monks were imported into the U.S. from Brazil and
Argentina during the 1970s, 80s, and early 90s, and thousands more are produced
each year at breeding facilities to satisfy consumer demand for inexpensive small
parrots. As a result, large numbers of naturalized monk parakeets now nest in
at least 11 states. These flocks are the inevitable result of the exploitation
of exotic birds by the pet industry.
Some conservationists worry that non-native birds pose a threat to native bird
populations, therefore the ‘intruders’ should be exterminated. Starlings,
pigeons, and monk parakeets have been dubbed ‘invasive species’—ones
that displace native wildlife and disrupt ecosystems—and have become the
target of multiple—and futile—lethal control efforts.
It is important that those who demonize non-native species remember that native
bird populations are impacted by a wide variety of factors, most of which arise
from human-caused habitat destruction and pollution. Parrots and pigeons tend
to inhabit urban areas where many native plants and animals have already been
driven out by North America’s most invasive species—Homo sapiens.
Moreover, decades of poisoning efforts have failed to produce lasting reductions
in starling, pigeon, and monk parakeet populations.
The Public Health and Safety Smokescreen
Officials who support the killing of non-native birds often use public health
risks as a justification for lethal measures. But these supposed risks do not
hold up under scrutiny.
For example, in a recent letter to the Animal Protection Institute, the University
of Illinois defended its practice of poisoning starlings who congregate around
the campus cattle barns. School officials assert that starlings are “known
carriers of disease that can be transferred to both humans and domestic animals.” This
statement, however, is true of just about any animal, including domestic dogs
and cats, and the cattle in the school’s own barn! Even humans are known
carriers of serious, infectious diseases.
Further, according to the National Institutes of Health, casual exposure to bird
droppings will not place an individual at risk of developing disease. The University
has yet to produce evidence that the birds in question pose a significant risk
to worker health that either meets or exceeds the risks posed by exposure to
the abundant livestock manure in the area, or that the risk posed by the presence
of the birds is greater than the risks posed by the spreading of the toxic poisons
that would kill the birds.
Histoplasmosis and psittacosis are two diseases that can be contracted from contact
with birds or bird droppings, but transmission of disease between humans and
free-living birds is extremely rare.
Histoplasmosis is caused by inhalation of spores of the soil-inhabiting fungus
(histoplama capsulatum), which grows where bird droppings accumulate. The greatest
risk of disease occurs when droppings accumulate for over two years on shaded
soil where large numbers of birds (or bats) have established roosts. Fresh bird
droppings do not support the fungus.
Psittacosis—an infectious disease with mild, non-specific flu-like symptoms—can
infect humans by breathing in the organism when the urine, respiratory secretion,
or dried feces of infected birds is aerosolized (i.e., dispersed in the air as
very fine droplets or dust particles). Other sources of exposure include mouth-to-beak
contact, a bite from an infected bird, and handling the plumage and tissues of
infected birds. The Centers for Disease Control (CDC) reports that, “although
all birds are susceptible, pet birds (parrots, parakeets, macaws, and cockatiels)
and poultry (turkeys and ducks) are most frequently involved in transmission
to humans.” The CDC cautions that individuals most at risk from contracting
the disease include bird owners, pet shop employees, veterinarians who treat
birds, and people who work in poultry processing plants.
It is rare that a genuine public safety threat is at the heart of a conflict
between birds and humans. More often, aesthetics or economics are the spurs for
lethal control, an approach whose effects are short-lived and wrought with environmental
and ethical conflicts.
The Problem with Poison
Lethal control methods are more than just cruel; they are also ineffective in
the long-term. For example, poisoning must be repeated year after year to offset
the high reproductive rates of animals such as pigeons and starlings.
Two poisons commonly used to kill starlings and pigeons are DRC-1339 (also called
starlicide) and Avitrol. DRC-1339 was designed to be a slow-acting poison that
causes birds to die slowly and to exhibit behavior associated with excruciating
pain. In blackbirds, for example, DRC-1339 takes up to three days following ingestion
to cause mortality, by way of irreversible kidney and heart damage.
Avitrol is commonly used in urban settings to control pigeons. Avitrol’s
main ingredient, 4-Aminopyridine, is a slow-acting nerve agent. There is no antidote
for Avitrol. Birds who ingest even as little as one kernel of Avitrol-poisoned
corn exhibit symptoms such as hyperexcitability, salivation, severe tremors,
erratic flight, and convulsions. These reactions begin anywhere from 10 to 15
minutes, to four hours after ingestion. Some birds take as long as two days to
die. Avitrol persists in the environment and can remain in the soil for up to
three years.
In addition to being cruel to their intended targets, such poisons pose risks
to other living beings. Children and companion animals may be harmed or killed
by coming in contact with poisoned bait or vomit from poisoned pigeons. In 2000,
the state of New York banned the use of Avitrol in cities with populations of
more than one million due to animal cruelty and public safety concerns.
Non-lethal Control
Fortunately, there are humane non-lethal solutions that can make an area unattractive
to birds, thereby reducing bird presence to an acceptable level. Further, many
companies, including Nationwide Bird Control (www.nwbird.com) specialize in humane,
non-lethal bird control and provide deterrent products, as well as assistance
in administering them.
Examples of effective, long-term and humane solutions to conflicts with birds
include:
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Netting to exclude birds from structures.
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Balloons, holographic foil strips, and other visual deterrents that scare unwanted
birds away.
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Wood or metal fastened at a 60-degree or greater angle on ledges to prevent pigeons
from perching (they prefer a flat surface).
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Bird wires to keep birds from landing on ledges: ranging from single-strand wires
placed three to four inches above the ledge of the rail to a more complex wire
coil that is wound around a railing or fixed on a ledge.
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Discouraging feeding in public places.
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Commercial fogging agent Rejex-it, which prevents crop depredation from roosting
birds. Rejex-it is harmless to people, animals, and the environment, but is distasteful
to starlings and other birds, preventing them from roosting where the product
has been applied.
In dealing with conflicts involving naturalized, feral or ‘invasive’ animals,
it is important to remember that irresponsible human actions are usually the
true cause of the problem. We must ensure that our policies toward such animals
are not equally irresponsible. Birds, whether native or not, should not pay the
price for our mistakes.
Monica Engebretson is Senior Program Coordinator for the Animal Protection Institute
and an exotic bird specialist. For more information contact www.api4animals.org.
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