Hello Frank, Edwin and other taxonomists!
Frank, I don't deny that different calls don't qualify the splitting of
species at the moment but I am wondering why. Excuse the rough definitions
below, I haven't got time to check proper definitions at the moment.
After all, isn't the standard definition of a species - reproductively
isolated populations? Therefore, if it is believed that two taxa overlap
and don't interbreed or wouldn't interbreed if they did overlap then the
taxa are different species. To carry this argument through, if two
populations call differently to each other there would be every chance that
they wouldn't respond to each other reproductively.
If the two calling populations are well separated it starts to become a bit
of a problem, but what if two different calling populations abut. I guess
that what is needed is knowledge of calls across the range of a species to
see if the variation is clinal or sharp.
Any thoughts on this?
Cheers
Mick Todd
Griffith, NSW
At 05:32 PM 7/07/02 +0800, Frank O'Connor wrote:
At 19:28 05/07/2002 +1000, Edwin Vella wrote:
For many, the Western Shrike-tit is regarded as a seperate species to the
Eastern (Crested) Shrike-tit and according to one of the Taxonomy lists.
I have the Western Shrike-tit firmly on my life list along with the
Western Fieldwren (that is a different bird to the Rufous Fieldwren).
Regarding the Western Shrike-tit, its call is "very" different to the
Eastern Shrike-tit, I can't see anyway the populations can interbreed and
there are plumage differences. It is a very good "tick" to get. There
appears to be no agreed taxonomy and the current one is debatable! But
ofcourse it is upto you and your opinion on how you treat this species.
There is an agreed taxonomy. The standard taxonomy is still Christidis &
Boles published in 1994, and this is the list being used by Sean.
Schodde certainly separates Western Shrike-tit and Western Fieldwren. The
former is probably fairly widely accepted. There is still a lot of debate
about the Western Fieldwren. Ron Johnstone at the Museum of WA says that
the crown of the fieldwren gets more rufous the further that you head
north in WA. i.e. it is clinal and he doesn't agree that it is a separate
species. My understanding is that Christidis (& Boles?) are updating
their taxonomic list and that this will be published later this year.
I agree that the call of the Western Shrike-tit is different. But this is
not sufficient to make it a separate species. The calls of Magpie-larks
and Grey Shrike-thrush (to name two) vary greatly around Australia. The
latter has different colorations also.
So certainly keep a record of the different sub species that you have
seen, but in order to have a standard comparison, use Christidis & Boles
(1994) until it has been updated. This is the list used for birders'
totals posted on Tony Palliser's web site.
___________________________________________________________________
Frank O'Connor Birding WA http://members.iinet.net.au/~foconnor
Phone : (08) 9386 5694 Email :
Birding-Aus is on the Web at
www.shc.melb.catholic.edu.au/home/birding/index.html
To unsubscribe from this mailing list, send the message
"unsubscribe birding-aus" (no quotes, no Subject line)
to
Birding-Aus is on the Web at
www.shc.melb.catholic.edu.au/home/birding/index.html
To unsubscribe from this mailing list, send the message
"unsubscribe birding-aus" (no quotes, no Subject line)
to
|
