Does it really matter?
 
 Unless the species are split, IMO, it doesn't.  For one of the wrens (Marsh Wren I believe), the western and eastern races are very different in their behavior and song, yet they haven't been split, though some wren experts, such as Don Kroodsma (see Don Stap's "BirdSong"), will say that there are ten species of wren in North America, and not nine.  Even for wrens, it doesn't matter if one sees the western or eastern race of this species, as the Marsh Wren is still one species. 
 
 Good birding,
 Richard
 
Richard L. Wood, Ph. D.
Computational Chemist
Cockeysville, MD 21030


----- Original Message ----
From: Paul O'Brien <>
To: 
Sent: Thursday, February 16, 2006 11:36:24 AM
Subject: Re: [MDOSPREY] Note on Baltimore Nashville Warbler

Has anybody looked at the Carroll Park Nashville Warbler to determine whether 
it is the nominate eastern ruficapilla or the western ridgwayi?   The major 
clue for ridgwayi is constant tail pumping, like a Palm Warbler.   Eastern 
birds can pump their tails occasionally, or even continuously if they are 
agitated, such as a migrant that has just dropped in after a long flight.   Plumage 
differences are subtle but include reduced contrast between head and back and 
increased contrast between back and rump, which is a bright yellow-green in 
ridgwayi.   The yellow of the undersides is brighter and a more pure yellow than 
in ruficapilla and there is a bit more white in the vent area.   All these 
characters are a matter of degree, but are discernible in the field if you get a 
good, long look.

At such a late date, a western vagrant may be as likely as an eastern 
holdover.

Paul O'Brien
Rockville, Mont. Co., MD