Hiked up Haycock Mountain near Lake Nockamixon this morning. Lots of birds singing, but not as many warbler species as I might have hoped (only 9--best being 1 Blackpoll Warbler). I did have dozens of singing Ovenbirds and Black-and-white Warblers. Also lots of Rose-breasted Grosbeaks, Scarlet Tanagers, and nest-building Baltimore Orioles. My best bird was probably a Yellow-throated Vireo--not a bird I see many of around here.