The question of the relation to speciation of calls is interesting. On
going research in Amazonia in revealing some interesting results, which
will probably result in a huge expansion in the number of species. One
antshrike is going to be split into eight species. Careful field work
has shown that the big bold continuous sweep of distribution shown in
field guides is a myth. The reality is eight separate pockets.
Ecological data shows the populations have been separated for a long
time. They look slightly different, and all have somewhat different calls.
Another point is that several studies that have suggested on the basis of
call that we are dealing with several species have later been supported
by molecular techniques. I am also reminded of a paper which showed in
relation to the hypothesis that rivers are a more important speciation
mechanism in Amazonia than the alternate advance and retreat of the
forest. That found that individuals quite close but on opposite sides
of the Napo river were more genetically different than birds further
apart but on the same side of the river.
John Penhallurick
On Wed, 22 Mar 1995, Bill Venables
wrote:
> >>>>> "Tony" == TPALLISE AU ORACLE COM <>
> >>>>> writes:
>
> Tony> ... Anyway it is quite clear that something is going on
> Tony> with this species. Could the same species call differently
> Tony> when in a different habitat i.e. rain forest as opposed to
> Tony> sclerrophyl forest? Or are we looking at different species
> Tony> altogether? I would have thought the latter more likely.
>
> This argument has been used before, I thought, to separate the
> chiming and chirruping Wedgebills, but in that case the habitat
> was not all that different - basically arid rangelands. In that
> case I think the general opinion has now swung back to a single
> species, but I haven't kept fully abreast of the arguments.
>
> I have noticed that the calls of at least two other birds - red
> wattlebird and grey shrike-thrush - can be quite different in the
> Adelaide Hills and the Flinders Ranges. On the other hand the
> Willie wagtail has a remarkably uniform call everywhere I have
> ever heard it in Australia.
>
> Bill
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