Perhaps "migratory" waders should be regarded as resident species that
travel elsewhere to breed. Most species of waders seem to spend more
time out of their breeding range than in it. This could be argued to
apply to most migratory species.
Cheers,
Carl Clifford
On 27/11/2009, at 10:35 AM, John Tongue wrote:
The whole question is really quite complex. Migratory birds can't
really be considered to have 'maintained' a breeding population here,
but we still count them. Then what about waders that turn up
periodically - Hudsonian Godwit, for example? Presumably listers are
still able to tick them? Then, what about Grey-headed Lapwing?
Isabelline Wheatear? And so the complexities multiply. In terms of
one's own life list, you just need to be happy with the rules you
apply to yourself. And if you want to compare and contrast life
lists, then you just need to be using 'common' rules.
Anyway, that's my two bob's worth.
John Tongue
Ulvertsone, Tas.
On 27/11/2009, at 9:55 AM, Dave Torr wrote:
Seems one of the ongoing questions on Birding-Aus is "is xxxx a
tickable
population". There seem to be two easy alternatives - either we
count no
introduced birds or we count them all. That would save a lot of
debate I
guess.... :-)
Slightly more seriously - I guess it is very hard for anyone to
determine in
many cases whether the population has been self-sustaining for the
required
period of time (10 years I believe?). How do we know for any of these
populations whether or not there have been further releases to boost
the
population - I recall that someone reckoned the Melbourne Bayside
Barbary
Doves were being replenished by further releases from time to time?
Does
being fed artificially stop them being self-sustaining?
2009/11/27 Bill Stent <>
I feel somehow that the Melbourne populations aren't tickable, but
I'm
looking for a good reason why not.
I'd be surprised if there were more than a dozen or so, which would
suggest
they might be partially supported by human feeding (although I've
got no
actual evidence for this).
Bill
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