Hi Carl,
It is certainly an interesting topic. There's a theoretical side of things,
and also the practical/economic side of things to consider. On the
theoretic side of things, Cattle Egrets possibly could be considered as
feral/introduced, though self-introduction from a native population is in my
mind a natural process (assuming that is what happened). On the practical
side of things, controlling Cattle Egrets doesn't appear to be necessary or
financially viable. And if Canada Geese reached the kind of numbers that
Cattle Egrets are in, I doubt we could afford to control them either, even
if it became necessary.
As for the point about the Dingo, well while the cutoff is arbitrary in some
respects, how far back do you go? I remember a few years back on this forum
being corrected on calling House Sparrow a native of England because the
Romans introduced them 2000 years ago (I'd appreciate a reference on this if
anyone has one, since I couldn't verify it when I tried). I doubt there'd
be too many English birders that would consider House Sparrow a feral in
England.
Regards,
Chris
On Jan 10, 2008 12:28 PM, Carl Clifford <> wrote:
> Dear All,
>
> When does a species become a feral and when does it become a native?
>
> Most Australian birders would regard the Cattle Egret as a native,
> but shouldn't it be classed as a feral? It was introduced, possibly
> unsuccessfully, to Derby WA in 1933. It then appeared, in large
> numbers in Oenpelli NT in 1948 and reached Colac Vic in 1949 and now
> it is pretty well ubiquitous. As the species is highly mobile and
> considerable numbers move between northern Australia and the
> Indonesian Archipelago, it is potentially a serious vector for avian
> diseases. Should they be culled?
>
> Hanzab describes a colony of Cape Barren Geese at Tidbinbilla ACT as
> feral (V 1-b p1196). Should they be culled, after all they do compete
> with other native grazing water birds for an often scarce food
> rescource?
>
> Off the Avian track, but equally interesting, the Dingo. This man
> assisted migrant has caused considerable damage to the numbers of
> native mammal species and may very well have caused the loss of some
> species. It is regarded as a native, but meets many of the criteria
> for a feral, so what is it?
>
> I would be interested in peoples opinions on this. I find that the
> line between feral and native a very wavery one which appears to be
> drawn nearly at random.
>
> Carl Clifford
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