A heads up to keep an ear out for this song in any woodlot, but especially ones that are dank and have dense tangles and a coniferous element (aka Stony Swamp NCC trails). This species’ song is loud and piercing (similar to a Northern Waterthrush in that regard). Like other passage warblers, this species sings while it forages, so the ability to recognize their song is vital. The exciting part is that late afternoons through to the early evening (after work hours) are as good as any for searching for this highly-prized species. For example, I am heading out around 6:00 PM today in search of one!
Migration window in spring here in Ottawa is typically May 24-31.