Hi tweets,

I've been contemplating weighing in with a bit of skepticism on the old
dread cat thread.

It is now the "common sense" that domestic cats are a terrible scourge of
wild birds, killing billions each year (the exact numbers vary considerably,
but are typically astronomical). I've always felt these numbers might be
somewhat inflated estimates extrapolated from a rather narrow base in fact.

Anyway, I've reviewed "Cats and Wildlife: A Conservation Dilemma" by John S.
Coleman, Stanley A. Temple, and Scott R. Craven, published in the Salem
Audubon Society newsletter, the Kestrel, May 1997. They cite an estimate
that between 8 and 217 million birds are killed each year by cats in
Wisconsin! That's a rather wide range for starters, with the higher figure
beyond belief, since one might extrapolate from that to the USA something
like 10 BILLION birds per year. Really! How many birds are there in the
world at any given moment? Cats can't have killed them all.

How do they arrive at these figures? Well, they cite one report that a
single feral cat may have killed 1000 birds in one year. In the next
sentence they report another study that concluded that one population of
"free-living, small-town" cats killed on average 14 "wild animals" per year,
which translates to three birds per year, based on another study that showed
that free-ranging cats prey is 70% small mammals (e.g., rats, presumably)
and just 20% birds. Sounds like that one cat was the feline equivalent of
Hitler. Was that one cat the basis of the extrapolation to the number of
birds killed by the estimated 100 million cats in the USA? (Actually, no,
because, if 100 million cats each killed 1000 birds per year that would be
100 BILLION birds... an unlikely total, but just 10x that of the high
Wisconsin estimate.)

Another point noted in this article was the fact that, while more rural
families own cats (60%) than urban families (30%), there are considerably
more urban than rural families in the US. I am one of those urban families,
and we currently have two cats, which from time to time are allowed out in
the back yard (a bad move, I know, but it reduces the pressure on the cat
box). Over the years we've had many more. Of the approximately 10 cats we've
housed during the past 30 years, to the best of our knowledge only two ever
killed a bird. The rest lay around the house, chased a squirrel or two (what
they would have done if the squirrel had let them catch them, I don't know),
snarled out the window at the neighboring pigeons, but we're never motivated
to carry through on their feline instincts. Our current killer cat, Diva,
just brought in a black rat yesterday. It was still twitching between her
jaws as she approached the back porch with her prize. She gave a quick
upward jerk of her head, tossed up the rat , and killed it by breaking its
neck. So far this year she's brought in one other rat and two or three
juvenile house sparrows.

My point is, that most house cats live in urban areas. Maybe 10% of these
kill any birds at all. Those that do kill birds probably kill mostly urban
birds, like House Sparrows, which could benefit from a bit of predation,
along with lots of urban rats and mice (which may well have been the
original motive for their domestication, in Egypt 4000 years ago). So,
perhaps rather than a blanket condemnation of pet cats, we should
distinguish the potential impact of cats in urban versus rural areas. It
would be best to keep rural cats inside, or cats with demonstrated predatory
inclinations, or cats with access to feeders that attract birds whose
populations are under some real threat.

Granted, cats have extirpated populations of island endemics, but that is a
very special case, one that requires agressive cat control measures.
However, I remain unconvinced that domestic cats should be ranked right up
there with habitat destruction, DDT, and mass commercial exploitation as
primary threats to our native birdlife.

Gene Hunn.