The Western Flycatcher split however is widely disputed by knowledgeable
observers. The split is poorly justified and based on inadequate data.
A cline in vocal parameters can be shown to exist across the northern
tier of Washington counties and the southern margin of British Columbia
that bridges the "gap" presumed to exist between the types.

Gene Hunn.

On Wed, 7 Feb 1996, Jerry Tangren wrote:

> David Wright wrote,
>
> >Consider the case of Baltimore and
> >Bullock's orioles. Originally these populations were recognized as
> >distinct species. Later, the AOU decided they were really subspecies of
> >a single species, so they lumped two "species" into a single one,
> >Northern Oriole (also Abeille's oriole was lumped in here, too, I
> >think). But the *taxa* involved -- the populations in question and the
> >more-inclusive taxon that embraces them -- remain unchanged; all that
> >has changed is which one(s) we call species. Now the AOU is reversing
> >its early conclusion and splitting/unlumping Northern Oriole. Now the
> >AOU is reversing its earlier conclusion and splitting/unlumping Northern
> >Oriole.
>
> The Northern Oriole is not simply a change in man's interpretation, the
> populations involved did NOT "remain unchanged." The split is on the basis
> of a change in the nature of the hybrid zone on the Great Plains. In
> locations where previously hybrids only existed, both Bullock's and
> Baltimore now co-exist. This is a highly dynamic situation and illustrates
> exactly the point you are trying to make.
>
> Jerry_Tangren at tfrec.wsu.edu
>