I have had good levels of migrant activity in my yard today and 
yesterday Morning. (My yard borders the Twinbrook section of Rock Creek 
Park). Few warblers, but yesterday I had three Rose-breasted Grosbeaks 
and at least one (probably two) Scarlet Tanagers. This morning I was 
surprised and pleased to see among the migrating robins a Summer Tanager 
foraging in the trees along with another RBG. It's an uncommon bird in 
the county, and the first I have seen here this year.

Good birding!
Jim Moore
Rockville, MD