Thanks to Bob for posting our sighting of the Empid in Monkton this morning.  Unfortunately I could not stay longer due to Thanksgiving arrangements.  I can provide some details though.  
 
I arrived at 7:45am and walked the area north of the abandoned house where there were several flocks of birds.  Mostly Juncos and White-throats, but kinglets, chickadees, titmice, woodpeckers, and a Purple Finch were also present.  Around 8:30am Zach Baer arrived and the bird activity had actually decreased.  Debbie Terry and Jim Stasz walked up at about 8:45 and while I was talking with them, I spotted the bird 25 feet up in a tree right next to the trail.  The bird became quite active with tail-flicking and flitting around.  A few times it ate berries next to the trail.  
 
Reasons why we thought it was a Western:
Though most of my viewing was through a camera lens, I could see most of the important field marks.  My first impression was a dull brownish-yellow flycatcher with little contrast.  The middle of the lower belly was the brighest yellow as on most Empids.  The was no contrast from what I could tell between the back, head, throat and upper chest.  The eyering was bold, but I could not say if it was strongly tear-dropped shaped [Just talked with Jim Stasz who says that it has a strong teardrop after more prolonged views].  The bill was relatively wide with a completely yellow lower mandible.  The head was peaked.  Debbie remarked that the wing bars were buffy.  I didn't make any notes on them, but my impression was that did not strongly constrast with the wings.  
 
I recommend reviewing Kaufman's Advanced Birding for overall Empidonax identification before going to see this bird.  It helps when knowing what to look for.  Also, if you have it, Birders Journal Vol 8 No. 2 has an excellent article on separting Western and Yellow-bellied by Matt Heindel.  As for separating Pacific-slope and Cordilleran, a recording will be needed and even that may not be enough.  
 
Jim mentioned that the bird is still being seen and is very active.  I have to get ready to travel.
 
Matt Hafner
Bel Air, MD