Re species,
I am following the discussion on species and calls with interest. I have
heard of several examples where females of one species (geographically
isolated and quite distinct) will mate preferentially with another species
(all be it closely related) when the two species are brought together. It
seems that this preference is based on a novel display.
the old female selection model of call and display improvement comes into
play. Some species of frog (which appear to have recently split from one
another) may have initially done so on the basis of a call being an
isolating mechanism. The species are sympatric and do not appear to be
interbreeding. I know of current research on some of the Agamid Lizards
where displays appear to isolate one sub species form another in areas of
overlap.
Brendon Neilly
-----Original Message-----
From:
Behalf Of Michael Todd
Sent: Monday, 8 July 2002 8:53 PM
To: Frank O'Connor;
Subject: More South West Adventures
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
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>
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