A nice post Brian.  Your argument about neutering is one I've made several
times on the FML, and once one of my major reasons on the "Ferrets Can't
Go Feral in California" list sometime back.  Its absolutely true, but, for
reasons I'll explain in a moment, I didn't include it for a good reason.
 
Your argument about minimun numbers is also a good point, and one I've also
made in the past (and on the list).  However, you can always find someone
happy to point out that on an Atlantic Island are a colony of squirels, all
descendants of a single pregnant female.  That means the colony started at
"1." It is thought such things has occurred before on isolated islands,
usually with rats, birds, or amphibians, but in reality, the instances are
quite low.  There is a growing realization that the minimum numbers to
insure colony success and genetic viability varies with the species,
birthrate, genetic variability, and type of food they eat.  So it is much
easier for a herbivore squirel to establish a colony on a predator filled
island than it would for a strict carnivore ferret.  Which is why, with the
exclusion of cats and dogs, all the introduced mammals in CaCa Land are
either strict or primary herbivores.  Even with the dog and cat feral
populations, there is evidence that they require constant replenishing in
order to maintain numbers.
 
Most scientists argue you need a minimum of 250 pairs of breeding
individuals (the Rule of 500) to maintain genetic vigour in a colony.  If
this was absolutely true, the species such as the California condor and
the black-footed ferret are doomed.  Perhaps with our genetic knowledge
increasing as fast as it is, that may not be true, but I for one am
pessimistic regarding their future.  This number is also somewhat of
mammaliann average, because highly varible, fast reproducing mammals need
less breeding pairs than slow reproducing, genetically similar mammals.
In other words, you would need more pairs of elephants than house mice to
create and maintain a viable colony.  But I didn't include this argument,
the argument about neutering, nor several others in the post when looking
at the differences between New Zealand and California for a single, simple
reason.  I wanted to address a "worst case" situation.
 
The CaCa Flushing Gestapo always works from the worst case possible
position.  The reason I didn't mention those other things is because I
wanted to show that even in the worst possible case, the chances of ferrets
forming feral colonies in CaCa Land would be astronomically small.  The
above two arguments are perfect in answering the question, "What would
happen if a hobby breeder released their ferrets," or "Suppose Bob C is
visiting the state and his 20 ferrets are turned free."  But they can't
answer the question, "Suppose a truckload of breeding pairs crashed and
hundreds of survivors escaped?" That is the sort of question the Flushing
Gestapo would ask, and the type of question the post was meant to answer.
 
So the post was written assuming large releases of unneutered ferrets (and I
should have stated as much).  Would those make it in California?, and the
answer is no, because of the reasons given.  Has such an occurence taken
place on USA soil?  Yes it has; when the ratting market crashed in the late
1920s due to the introduction of rat poisons, Ohio ferrets were let out of
their cages to fend for themselves.  They didn't.  No feral colony of
ferrets exist in Ohio, even near "Ferrettown." When I have some time, I plan
on visiting the area and searching through newspaper archives for stories
in that time period that report those occurences so second-hand information
can become documented.  (Perhaps Ohio FML readers with spare time could go
through the old newspapers, starting about 1900 and ending about 1935,
copying anything ferret related.)
 
My major point is that New Zealand is a unique and special place, which
does not compare to the ecological conditions any place else on Earth,
except for similar island environments.  Which does not include California,
because even if you tossed a thousand breeding pairs into the wilderness,
they would still have to evade predators, find prey, beat the competition,
and successfully raise offspring.  Sort of asking an old Ford Pinto to race
against a new Lotus.  Ferrets were selectively bred to *chase* rats and
rabbits out of holes, not kill and eat them, which is why dogs are used in
ferreting both rats and rabbits--to catch and kill them.  Now, if ferrets
were bred to do that, then they would be polecats or perhaps even mink, not
domesticated ferrets.
 
Bob C and 20 MO Poopinators
[Posted in FML issue 2250]