Similarly, it's quite possible that the original birds are producing young
every year, only to have them all taken by foxes, etc. Is it possible to
estimate the age of an ostrich from a distance?
Peter Shute
> -----Original Message-----
> From:
> On Behalf Of Chris
> Sanderson
> Sent: Wednesday, 27 October 2010 10:51 AM
> To: Tony Russell
> Cc: birding-aus
> Subject: Re: [Birding-Aus] NSW Ostriches
>
> Tony,
>
> As I'm sure you know, vagrants are treated differently only
> if they got themselves here. For a deliberately introduced
> feral, Australian birders typically use a "10 years breeding
> in the wild" rule, because it's easy, however as Nikolas
> points out that may not always make sense for things like
> Ostrich and Parrots which have long lifespans. However I
> think with birds breeding in the wild, 10 years could be
> enough to produce 3 generations (original birds having chicks
> which then have chicks etc.) as just because the original
> adults haven't necessarily died yet doesn't mean their
> grandchildren aren't already breeding successfully. So as
> far as I'm concerned, these Ostriches are as viable as the
> Peafowl or Pheasants on Rottnest Island, or Guineafowl
> wherever it is people can tick those. If you choose to tick
> ferals (and why not? They are a part of Australia's fauna
> now), then I say go for them!==============================
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