Janet,
   Unless you have had Black-&-white Warblers in your yard all summer this bird is probably a migrant. Notice the Yellow Book graph shows July 24 as the earliest arrival. Much of the arrival/departure date data was derived from banding records. The earliest for Montgomery County I have in the database is July 28. There has to be a first bird of the season some time before the peak of the migration. This year you spotted it.
--
Bob Ringler
Eldersburg MD


---- Janet Millenson <> wrote: 
> Just now I found a Black-and-White Warbler in my yard, gleaning the trunk of 
> a large maple. It's about two weeks after Atlas safe dates, unfortunately, 
> but a couple of weeks earlier than what the Yellow Book shows is the big 
> autumn push-through. I really get a kick out of these little "zebra birds." 
> Oddly, last night I dreamed my yard was full of migrating warblers.
> 
> Janet Millenson
> Potomac, MD (Montgomery County)
> 
> ----------------------------------------------------------------
> "Look at the birds!" -- Pascal the parrot