After coming home from birding in Va. this morning, I decided to go over to the Arboretum about noon, not expecting to see much at that hour.  I was surprised to hear and get good looks at a lifer Mourning Warbler.  He was in a thicket about 15 feet to the right (west) of where the paved road going up Mt. Hamilton meets the gravel path that leads around to the azaleas.  At this point are a few stumps and logs.  After I got my looks, he moved farther back into the woods but continued to call for awhile.  When I came back down the hill a few minutes about 1pm, I didn't hear him.

Other warblers seen or heard:  Magnolia, Blackpoll (actually on the ground at one point), Black-throated Blue, Northern Parula, American Redstart, Common Yellowthroat, and one Yellow Rump.  Also, seen were veery and woodthrush.

Tom Jones
Washington, D.C.