P.O. Box 1036
Bowie, MD 20718
7/24/2014 6:10 PM
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Countering the predation issue|
Question from Cathy:
I know you have addressed the wildlife predation issue before, but I
was wondering if you could give your top arguments of what you would
say when people bring up this discussion. The reason I ask is
that our group is working on developing a TNR program but we have one
guy with a wildlife degree who always quotes these studies about the
decimation on the wildlife population by these non-indigenous cats and
how they must be removed. Some people give him credibility because of
his degree and I'd like to have some short, well-thought out responses.
Nathan Winograd's response:
One of the golden rules of advocacy is to tailor your response to your
audience. You do not want to sound like an encyclopedia, nor do you
have to get overly detailed, nor do you have to know the intimates
about every study. Don't lose sight of the forest for the trees. You
are, in the end, an advocate. Respond succinctly, in a straightforward
and thoughtful manner.
My favorite strategy is to write a detailed, scientific position paper,
which is sent out to people in the community--the media, commissions,
city council, friends, allies, other groups, VIPS, caretakers, whoever
your target audience is. But when I make speeches, when you actually go
before the commission, or council, or are interviewed by a reporter, I
make a different argument--one of compassion, and lifesaving. That two
pronged approach (scientific analysis on paper to rebut the claims of
Mr. Wildlife Degree in your community, and a broad message of showing
kindness to cats in person) is effective.
I always start with the efficacy of TNR for all the reasons I won't
repeat here. How it works, how it reduces impounds and deaths in
shelters, how it protects public health. I always end with the humane
argument. How the cats are out there through not fault of their own.
And how we can choose kindness over killing. In the middle is the nuts
A. The starting point of any analysis in assessing wildlife predation
is a two fold inquiry: 1. does the species exhibit predatory behavior?
and, 2. how much? In other words, does the predatory behavior adversely
affect the prey populations? "In biological systems it is insufficient
merely to have found one animal will eat another, that is what
predators do--[the more important question is whether that] is
predation within normal limits." (Tabor, The Wild Life of the Domestic
Cat, Arrow Books, 1983.) In short, is there evidence that cats actually
negatively impact the prey populations?
Paul Errington identifies the problem: "Preying upon a species is not
necessary synonymous with controlling it or even influencing its
numbers to any perceptable degree. Predation which merely removed an
exposed prey surplus that is naturally doomed is entirely different
from predation the weight of which is instrumental in forcing down prey
populations or in holding them at given approximate levels." (See Ellen
Berkeley, Maverick Cats: Encounters with Feral Cats, New England Press,
B. The studies cited by Mr. Wildlife Degree not only utterly fail to
address the impact of cat predation, but they are severely flawed in
their methodology. (I SAY THIS WITH A FAIR DEGREE OF CONFIDENCE,
BECAUSE EVERYONE ON THE ANTI-CAT CITE USES CHURCHER'S STUDY IN ENGLAND
AND THEN COLEMAN'S STUDY IN WISCONSIN FOR THE PROPOSITION THAT CATS ARE
Chucher looks at what kind of prey cats were bringing home in an
English Village. He then extrapolated from that to come up with how
many cats were killing birds across Great Britain. So, for example, if
10 cats bring in 100 birds, then 1,000 cats kill 10,000 birds, and so
on. By guessing as to how many cats were in Great Britain, Churcher
concluded with an astronomical number of killed birds. But is science
really that simple? For one, how did the birds die? did the cats kill
them? were they roadkill? were they fledglings who would have died
anyway? was there any indication of disease in the prey? was the catch
freshly killed or were the cats dead for days? Being scavengers more
than predators, few cats would pass up injured or dead birds? In fact,
Churcher has no qualitative information whatsoever. All of this missing
information could have been supplied with little additional effort.
For example, two French researchers Moller & Eritzoe examined birds
killed by cats vs. those that met accidental deaths by crashing into
windows. They examined the birds for various factors, the most
significant of which was the health of the bird. They found that while
windows were non-discriminating and killed healthy and sickly birds
equally, the birds cats killed were significantly sicklier than those
who crashed into windows, with 70% of them slow movers and fledglings!
But more importantly, Churcher ignores that several hundred birds in
his village must die each year to maintain a stable population, that
the highest number of birds brought home were at the time of the first
broods (lots of already doomed fledglings!), and that the village's
bird density was 9 x higher than the rest of Britain?
So taken together, what does Churcher actually prove? "Taken together,
these elements suggest another interpretation: cats are simply weeding
out birds from an overcrowded population. Nor are they apparently
catching healthy birds at their peak of winged life; wintertime is most
stressful on birds that are old or sick, and fledglings tumbling down
from nests could account for the high count in early summer. And with
only 130 dead sparrows recorded by Churcher, the cats kill--or
find--less than half the numbers that must be annually culled to
sustain their populations." (J. Elliott, "Of Cats and Birds and
Science: A Critique of the Churcher Study," 1994.)
Two years after that original "study," all pretensions of scientific
objectivity disappear. In his second paper, he describes cats as
"ruthless killers," predation as "the slaughter," while prey is a
"luckless mouse," or a "very frightened baby rabbit." Is this science?
Coleman in Wisconsin is even worse. In his paper, "Cats and Wildlife: A
Conservation Dilemma," Coleman states that "Recent research suggests
that rural free-ranging domestic cats in Wisconsin may be killing
between 8 and 217 million birds each year," citing footnote 10. And
what is footnote 10? An article in Wisconsin Natural Resources written
by HIMSELF. Coleman cites himself. So let's look at the article. What
does it say? "Here are our best GUESSES at low, intermediate and high
ESTIMATES of the number of birds killed by rural cats in Wisconsin"
BASED ON THE SAME OVERSIMPLIFIED, HGH SCHOOL LEVEL FORMULA THOROUGHLY
DISCREDITED IN THE CHURCHER STUDY. For one, it is not RESEARCH. It is a
GUESS. Second, there is no basis for the number of cats he GUESSES live
in Wisconsin. Third, is a range from 8 to 217 million a statistically
valid range? Absolutely not. It shows a shockingly low level of
scientific rigor and confidence. Finally to get at his low and high
estimates, he ASSUMES cats kill rate is 20% on the LOW end and 30% on
the HIGH end. Is this fair? Studies in nine states had the range as
"Few" on the Low end to 3% and 20% on the high end. If you eliminated
the Few and the 20% which are off the curve, it would be a 3% range to
14% on the high end for percentage of total prey being birds. A New
Zealand study had it pegged at 5% by scat analysis, in Australia it was
5.2%, and another study in New Zealand had it at 4.5% in only 12% of
the cats! Coleman's numbers are off the charts and over inflate his
"findings." But even then, he is making assumptions that aren't valid:
he assumes millions of cats, he assumes they are all allowed outdoors,
he assumes they are all young and agile and able to hunt equally, and
he assumes each one is regularly killing birds despite the fact that as
many as 50% of people do not let their cats outdoors, that American
cats are getting fatter and less agile, that American cats are living
longer and cannot hunt as well as they get older, and that some cats
are just lazy or lousy hunters.
Coleman is a guess, not a study. It is, worse, a bad overly inflated
guess. In an interview with a reporter in 1994, even Coleman admitted
as much: "The media has had a field day with this since we started.
Those figures were from our proposal. THEY AREN'T ACTUAL DATA; that was
just our projection to show had bad it might be." But that hasn't
stopped anti-cat groups from using the stuff as if it was handed down
from Mt. Sinai.
C. There is a large body of scientific literature that is ignored by
Mr. Wildlife Degree, precisely because it contradicts his conclusions.
Roger Tabor found that cats have low success as bird hunters and that
the bulk of their diet is garbage, plants, insects, and other scavenger
material. In short, cats are not impacting bird populations on
continents. Fitzgerald & Karl found that "cats suppress populations
of more dangerous predators such as rats and thus allow denser
populations of birds than would exist without them." Robert Berg found
that cats were not impacting quail population in San Francisco even
though quail nest on the ground. Mead found no evidence that cats are
impacting overall bird populations. Colemand & Brunner concluded
that "The common belief that feral cats are serious predators of birds
is apparently without basis." A Worldwatch Institute 1994 Study found
that birds are in decline due to drought, habitat loss, overtrapping,
and water pollution. Cats are noticeably absent as factors. A 1988
study by the University of Georgia blamed forest fragmentation across
Southern U.S. for decimating songbirds. A Colorado Wildlife Dept. study
in 1994 blamed drought. National Geographic lined declines to poisons
in environment, particularly lawn care products.
C. TNR actually helps meet the goals of Mr. Wildlife Degree because...
(Here I would note all the reasons I mentioned in past posts, which I
won't repeat here, about the alternative being do nothing, meaning cats
are breeding, roaming and foraging for food, I would note that
neutering significantly reduces roaming which means less contact with
wildlife, and I would note that even if the cats were killed, other
cats would move in to fill their territorial void left by cats). Less
cats, controlled feeding, means less hunting. Here, you might also note
that many studies have found that upwards of 75% of birds killed by
cats are non-native starlings which compete with native birds for
habitat, so that the net effect of cat predation may actually be
complementing the goals of native species advocates.
D. Where does it end? If we must kill cats because they kill birds,
where do we draw the line? (some think this argument is silly, but I
have found it very useful as the media tend to like it a lot.) A lot
has been written about the supposed controversy surrounding feral cats,
much of it of dubious value. Common sense, not statistics or hard-line
arguments, could have pointed the way, as it did as early as 1949 when
then-Governor Adlai Stevenson of Illinois, vetoed a bill to restrain
cats: "We are all interested in protecting certain varieties of birds.
That cats destroy some birds, I well know, but I believe this
legislation would further but little the worthy cause to which its
proponents give such unselfish effort. The problem of cat versus bird
is as old as time. If we attempt to resolve it by legislation who knows
but what we may be called upon to take sides as well in the age old
problems of dog versus cat, bird versus bird, or even bird versus worm.
In my opinion, the State of Illinois and its local governing bodies
already have enough to do without trying to control feline
delinquency." So why, 50 years later, is Mr. Wildlife Degree still
belaboring the point?
E. Indigenous vs. non-native wildlife. Mr. Wildlife Degree's proposal
to round up and kill cats because they are "non-native" is based on a
troubling belief: value comes from lineage, and worth as a species
stems from being here first. The belief that some species of animals
are worth more than others because they were here first is
backward-thinking and shortsighted. But it is hardly surprising. The
call for extermination of animals in the name of protecting others
deemed more worthy by some arbitrary standard is not new. "Cats kill
birds, so we must kill cats." This is the banner under which Mr.
Wildlife Degree and other native species advocates have long rallied to
label cats as "pests" of our cities and "invasive non-native" intruders
in our parks and countryside.
But cats aren't the only ones to be targeted for slaughter in the name
of protecting other species or preserving "native" habitats. They have
been joined at different times and in different places by red foxes,
gulls, cowbirds, elk, sea lions, coyote, mountain lions, ravens,
skunks, raccoons, wild horses... the list goes on. Referred to as
"garbage animals," "alien" species, "weeds," and "vermin," these
creatures have become scapegoats for the massive habitat destruction,
environmental degradation, and species extinction causes by one species
and one species alone: humans.
For nativists, the point is clear: the lives of these animals don't
count, and therefore they can and should be eliminated to protect more
important species and to preserve "natural" environments. Had we
honored and preserved life, had we treated all animals--cats, birds,
and every other creature who shares our planet--with the respect they
each deserve, we might have spared many of the species now lost forever.
To us, there are no "garbage" animals and slaughter and death aren't
the tools we need to preserve life. To do that--to preserve the life of
all animals--we believe we must honor and preserve the life of each.
I hope that is a helpful starting point.