Tweets:

Thanks to Hal for summarizing the interesting results of mitochondrial DNA
phylogeny in dabbling ducks.


At 11:52 AM 8/13/99 -0700, Hal Opperman wrote:

>Hare are some of the discoveries announced in this article. Expect these
>to be reflected in various ways in field guides and check-lists four to ten
>years out.

One can hope. I was disapppointed to find out how little decade-old
molecular results on the relationships of the various orders and families
were reflected in the third edition of the National Geographic field guide,
apparently because they were not reflected in the 1998 A.O.U. checklist on
which it was based. The only concession to the considerable data on bird
phylogeny collected by Sibley and Ahlquist (1990), Allen Wilson's group,
Mindel et al. (1997) and others that I noticed in NG3 is the statement
under New World Vultures (Cathartidae) that "Recent evidence indicates a
relationship to storks". Despite this statement, the Cathartidae are still
placed in their traditional position next to the Falconiformes rather than
next to the storks! Results supported by multiple lines of evidence, such
as the "primitive" (early branching) position of Anseriformes and
Galliformes relative to other N. American orders are ignored in favor of
the traditional but unsubstantiated view that loons and grebes are the most
primitive N. American orders.
While it may seem reasonable to retain the traditional sequence of orders
and families when there is conflicting data or insufficient evidence to
resolve relationships, I think this practice is a disservice to the birding
community. It fosters the notion that classifications are mere indexing
systems rather than hypotheses about evolutionary relationships and gives
the impression that no progress in understanding bird relationships has
taken place in the last 40 or more years. It is misleading for NG3 to state
that "The A.O.U. Check-list arranges species according to their presumed
natural and evolutionary relationships" without even a mention of the
substantial molecular evidence against the arrangement they use. Although
field guides (and the A.O.U. Check-list) are not intended to be treatises
on avian evolution, in practice most of us absorb a great deal of our ideas
about avian relationships from them, and it seems reasonable to expect them
to help us be aware of current thinking on evolutionary relationships
rather than to trail decades behind.
A phylogenetic tree (cladogram) in the introduction of a field guide could
summarize family relationships in a page; in two pages the alternative
schemes of traditional and more modern classifications could be compared.
Perhaps some of the more ornithologically savvy tweeters can explain to me
the seemingly misplaced conservatism of the A.O.U. checklist and field
guides with regard to classification. This geneticist has a hard time
understanding its purpose.

Paul Talbert
Fred Hutchinson Cancer Research Center
Seattle, WA
tuisto at oz.net