Thanks to Bill and Steve for getting this very interesting discussion
going, and to Andy, Bob, and Bob for clarifying some of the issues. I
think the Hackett et al. paper is very exciting. The passerines have to
be related to something, after all, and there haven't been any good
candidates 'til now.

But I'm writing for more of a "fun" take on the falcon-parrot issue. I
used to do a lot of field work in the mallee scrub forest in southern
Australia. On several occasions, the many songbirds that were flitting
and chirping and singing around us would very abruptly shut up and dive
for cover. Within a fraction of a second, one or a few Mallee
Ring-necked parrots would fly by, and within another fraction of a
second, the little birds would resume their flitting, chirping, and
singing as if nothing had happened, and this even when the parrots
landed nearby. Had I been at home, I would have thought a Cooper's Hawk
had flown through. The upshot is, if you get a chance to see a parrot
fly by, especially one with a long tail, squint your eyes for a moment
and think 'falcon'. You may, like I was, be surprised at the general
morphological similarity (big head, stubby downcurved bill, pointy
wings, fast flight, narrow tail) between some parrots and falcons!

Keith Tarvin (Oberlin)

----- Original Message -----
From: Bob Powell <[log in to unmask]>
Date: Friday, June 27, 2008 4:06 pm
Subject: Re: [Ohio-birds] Falcons closely related to Parrots?
To: [log in to unmask]

> I am glad Andy Jones has weighed in on this topic; he is
> incomparably better
> qualified than I to comment on the Hackett, et al. article in
> Science.  I
> would just like emphasize one general point from the point of view
> of (and
> for the benefit of) birders, who are generally not closely
> acquainted with
> genetics.  Nor am I for that matter, I just happen to have a talented
> step-daughter who is a geneticist and patiently explains things to
> me from
> time to time.
> First, many of the birders who have weighed in on this topic tend
> to confuse
> phenotype and genotype.  This is the old "if it walks like a duck
> and quacks
> like a duck, it must be a duck" school of thought that dates back
> to before
> Linnaeus.  Unfortunately, biology is replete with examples of
> things that
> look very similar, but which are genetically quite distinct, and
> vice versa.
>
>
> The key objective in taxonomy is to find an objective measure of the
> differences between organisms.  In the nineteenth century, it was
> thoughtthat morphological measurements, properly arranged, would
> disclose the
> relationships between groups of living entities.  By and large,
> they pretty
> much got it right, but problems remained.
>
> Sibley and Ahlquist's DNA-DNA hybridization studies of the 80's
> were a big
> step forward and led to some deep insights into bird relationships.
> However, the DNAs of two different species can hybridize in a
> gazillionways and each way will have a different dissociation
> temperature.  The
> resulting noise in the measurements limits the resolution of the
> distinctions that can be made.
>
> The newer nucleotide sequencing techniques are based on the
> question "how
> many substitutions would I have to make to turn this gene into that
> one?" If many substitutions are necessary, the species must not be
> closelyrelated.  As Andy points out, 19 nuclear loci is a huge
> advance over most
> studies.  By contrast, the genetic "bar coding" project that
> stirred up so
> much buzz two years ago used no more than 600 base pairs on one
> locus of the
> mitochondrial DNA.
>
> The Hackett study is an enormous advance in resolution, but it too
> leavessome unanswered questions.  Andy mentions the time-honored
> conundrum  of the
> Hoatzin, the bizarre South American bird that clambers around in
> trees using
> the claws on its wings.  The new study also cannot confidently
> place the
> pigeons and doves, a widespread and numerous family known to just
> aboutevery human on the planet.
>
> So the search goes on.  With faster sequencers, better statistical
> methods, and bigger computers, we may one day be able to answer these
> questions.  Then we can move on to defining just what a species is
> and how
> come those ducks and gulls hybridize so easily.
>
> For those of you who can stand a little more depth, I recommend
> DevorahBennu's blog
>
>
http://scienceblogs.com/grrlscientist/2008/06/early_birds_shake_up_avian_tre.php
>
> for a nifty synopsis of the Hackett paper, including some nice
> graphics that
> dramatically illustrate the relationships between the clades.
>
> Cheers,
>
> Bob
>
>
>
>
> --
> Robert D Powell
> Wilmington, OH, USA
> [log in to unmask]
> http://rdp1710.wordpress.com
>
> Nulla dies sine linea
>
> ______________________________________________________________________
>
> Ohio-birds mailing list, a service of the Ohio Ornithological Society.
> Our thanks to Miami University for hosting this mailing list.
> Additional discussions can be found in our forums, at
> www.ohiobirds.org/forum/.
> You can join or leave the list, or change your options, at:
> http://listserv.muohio.edu/scripts/wa.exe?LIST=OHIO-BIRDS
> Send questions or comments about the list to: [log in to unmask]
>

______________________________________________________________________

Ohio-birds mailing list, a service of the Ohio Ornithological Society.
Our thanks to Miami University for hosting this mailing list.
Additional discussions can be found in our forums, at www.ohiobirds.org/forum/.

You can join or leave the list, or change your options, at:
http://listserv.muohio.edu/scripts/wa.exe?LIST=OHIO-BIRDS
Send questions or comments about the list to: [log in to unmask]