It is ramping up right now.
I can hear, out my window this morning, the songs and calls of Pine Warbler, Black and White Warbler, Redstart, Red-eyed Vireo (not exactly a warbler), Magnolia Warbler, Yellow Warbler, Black-Throated Blue, Parula, Prairie Warbler, and a few more that I am not sure about.
My idea of watching the spring warblers is a chaise lounge lawn chair flat, under a big old oak tree with binocs. Preferably, a big oak near some juniper trees - which is why I planted my junipers and Japanese willows: to watch the warbler migration with minimal exertion. Let them come to you. Just wait for them to pass through the trees. Otherwise, it's a day of neck pain. Knowing their calls simplifies it: you don't have to try to see them. But plenty of them forage silently in the treetops. Especially the odd vireos.
Get out there and see these little jewels of Creation, and listen to their morning calls, as they pass by on their trip north.
Image: A Peterson pic of a few Spring Warblers