I finally got around to looking at shrike specimens this morning (sorry,
I've been away from my desk for 4 days, actually went birding as well as
visiting Vancouver), and indeed, as Doug Kragh wrote, the nasal bristles on
top of the bill are black in Loggerhead Shrike, white in Northern. This is
in the adults; in immature Northerns (the majority of what we see in
Washington) they are pale tan, in agreement with the brownish overall
coloration. Of course, no one would mistake an immature Northern for a
Loggerhead, and immature Loggerheads become like adults by their first
winter. The bristles on the *side* of the bill base in Northern are black,
an extension of the very narrow black facial stripe that includes the lores
(as does the slightly wider one in the Loggerhead).

There are good ways to tell these shrikes apart, preeminent to me the
considerably paler upperparts of Northern as well as the obiously narrower
facial stripe; gives them a very different look in the field. If this is
"jizz," then it just proves that jizz is nothing more than the sum of parts
that can be easily described--not a bit of magic on the part of the
observer. Also, adult Northerns are finely barred beneath, always evident
although averaging less conspicuous than in first-year birds. Adult
Loggerheads are either entirely unbarred or may have faintly indicated
bars, especially early in the winter. I guess I'm saying that I hope the
ID is already cinched by the time you get close enough to note the nasal
bristle color!

Dennis Paulson, Director phone: (206) 756-3798
Slater Museum of Natural History fax: (206) 756-3352
University of Puget Sound e-mail: dpaulson at ups.edu
Tacoma, WA 98416