So we've been talking for a couple of weeks about spring migration. But birds were moving long before we started this campaign. And one of the earliest messengers was the Wilson's Warbler, which started pouring north from its wintering grounds in southern Mexico in early March. Check out the eBird maps below the fold:

Here's the map from February. We saw a few Wilson's at that time, a hint of things to come:

But then, Bam!, March:

And then, here we are, with today's map: