Black-and-white Warbler

We had another excellent morning on Amherst's Rail Trail, walking from Station Road. For the first time we had a number of Black-and-white Warblers (Mniotilta varia) in migration. Uniquely among warblers they behave like nuthatches, moving rapidly up and down trees in search of insects (mostly seeming to climb, and then flying down to start again). They were constantly in erratic motion, and I must have attempted at least a hundred shots to get this one. It's a male, with considerable black on the throat (females have white throats).

Other sightings included both pileated woodpeckers, the first gosling on the nest of a Canada Goose, swamp sparrows, and numerous birds carrying nesting material.

If I'm reading the BigBlipYear list correctly, this should be the first black-and-white warbler on it--they're not common.