You could go to the original source. The splits were published in a
recent issue of the Auk, the official publication of the American
Ornithological Union. I think it was the July 1997 issue but I'm not sure.
The oriole and scrub-jay splits were published in a previous article in
1996. I hear that the latest edition of the AOU checklist is at the
printer's and will be available sometime around January 1998.
The Auk is probably only available at a university library or from
you local ornithologist.
Birding, the official magazine of the American Birding Association,
recently had a very nice article on the different types of solitary vireos
(at that time they were subspecies).

At 06:57 26/9/97 -0700, you wrote:
>Tweets,
>
> I am familiar with the recent changes made by the AOU
>to species designations such as the scrub jays and (formerly) northern
>orioles, etc., but am not aware of the split of the vireos. These are now
>separated into Cassin's and plumbeous species based on earlier race
>distinctions?
> Could anyone suggest a reference to llok up a few of these changes,
>some of which may also have been overlooked.
>
>Thank you,
>Paul Duval
>
>

Deb Beutler
Department of Zoology
P.O. Box 644236
Washington State Univerisity
Pullman, Whitman Co., WA
dbeutler at wsunix.wsu.edu