The early green up and then cool down has everyone confused, including the warblers. I am just now beginning to hear Worm-eating Warblers in the numbers that I would have expected two weeks ago. Redstarts and Black and White Warblers are abundant in the forest. I am hearing a few Common Yellowthroats especially near the meadows.
We still have Black-throated Green, and Black-throated Blue Warblers singing at Mariton. I heard a Cape May Warbler earlier this week, along with a Parula Warbler. I don't expect these four species will stay for the summer to breed, but this year could be different. Many of the oaks further north suffered a lot of frost damage and it could affect insects (warbler food) in those areas. In the meantime, if you want to see warblers (or at least hear them) visit Mariton.