Concern
over the declining
populations of
certain bird species
has generated heated
debate about what
are the most effective
steps toward preserving
and restoring those
populations. Too
often
this discussion
becomes mired in
a simplistic cat-versus-bird
argument. Focusing
on the perceived
struggle between
cats and birds
diverts attention
from the real
cause of declining
bird populations:
the enormous impact
of the human species
on birds and their
habitats.
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Oil Refinery |
The major cause
of bird species
loss—indeed,
all species loss—is
habitat destruction.
Habitat modification,
fragmentation,
and loss is caused
by a myriad of
human activities,
including logging,
crop farming, livestock
grazing, mining,
industrial and
residential development,
urban sprawl, road building,
dam building, and
pesticide use.
In a 2000 report
by the World Conservation
Union surveying
1173 threatened
bird species, habitat
loss was the most
important threat,
affecting 83% of
the bird species
sampled. Across
the United States,
little land is
left untouched
by human development,
modification, fragmentation,
and pollution.
Already human activities
have led to the
extinction of ten
percent of the
world’s bird
species—in
some locales, that
number rises to
as much as 90 percent.
Today more than
a thousand bird
species are listed
as threatened,
and scientists
predict between
500 and 600 of
those will go extinct
in the next 50
years.
In the United
States, much of
the impact on birds
is a result of
America’s
growing population
and its even faster-growing
development of
land. Between 1990
and 2000 the U.S.
population grew
by 33 million people,
the greatest numerical
increase the country
has ever seen.
Future growth is
predicted to add
27 million people
each decade for
the next 30 years.
More significant
is that America’s
demand for resources
is growing disproportionately
to its population.
A Brookings Institution
analysis reveals
that urbanized
land increased
by 47 percent in
the 15 years
between 1982 and
1997, even though
population only
increased by 17
percent; population
in suburbs, meanwhile,
increased twice
as fast as population
in cities. Researchers
at Brookings predict
that by the year
2030, half of the
buildings in which
Americans live,
work, and shop
will have been
built after the
year 2000. With
this level of development
and population
growth, the serious
loss of bird species—due
to habitat destruction,
pollution, and
fragmentation—will
continue for decades
to come.
Considering the
vast scale of human
destruction of
bird habitat, arguing
about “cats-versus-birds” trivializes
the critical issues
facing bird populations
today. Cat lovers
and bird lovers
can agree: the
real danger to
birds is humans.
Habitat
Destruction Bibliography
BirdLife International
(2004). Threatened
birds of the world
2004. CD-ROM. Cambridge,
UK: BirdLife International.
Brooks, Thomas
M., Stuart L. Pimm,
and Nigel J. Collar. "Deforestation
Predicts the Number
of Threatened Birds
in Insular Southeast
Asia." Conservation
Biology 11 (1997):
382-394.
Dirzo, Rodolfo,
and Peter H. Raven. "Global
State of Biodiversity
and Loss." Annual
Review of Environment
and Resources 28
(2003): 137-167.
Jetz, Walter,
David S. Wilcove,
and Andrew P. Dobson. "Projected
Impacts of Climate
and Land-Use Change
on the Global Diversity
of Birds." Public
Library of Science
Biology 5 (2007):
e157, http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371%2Fjournal.pbio.0050157’.
King, David I.,
and John H. Rappole. “Population
Trends for Migrant
Birds in North
America: A Summary
and Critique.” Defenders
of Wildlife (2003).
Myers, Norman,
Russell A. Mittermeier,
Cristina G. Mittermeier,
A. B. Da Fonseca,
and Jennifer Kent. "Biodiversity
Hotspots For Conservation
Priorities." Nature
403 (2000): 853-858.
Pimm, Stuart,
Peter Raven, Alan
Peterson, Çagan
H. Sekercioglu,
and Paul R. Ehrlich. "From
the Cover: Human
Impacts on the
Rates of Recent,
Present, and Future
Bird Extinctions." Proceedings
of the National
Academy of Science
103 (2006): 10941-10946. |
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