Nashville Warblers are fairly common migrants in spring at Mt. Tabor (Portland). My sightings have always fallen between April 17th and May 26th. The peak is end of April/beginning of May. My highest count was 30 on 5/6/12, and that was an exact tally. I've also seen numbers in the 15-20 range on 5/1/07, 4/24/10, and 5/1/10. Still waiting for my first Nashvilles to show up here in Corvallis. Happy spring, Adrian