Strangers In Our Midst

There are new kids on the block and I'm having trouble identifying these pint-sized, red-headed strangers.  They are no problem, but I'd like to know who the invaders are.  I've never seen them before, that's for sure.  In outward appearance, they look very much like half-size woodpeckers, but these little birds are absolutely frenetic, flitting quickly here and there, and spending most of their time upside down.  They will hang head down from the tips of branches, pecking at whatever is on the end.  They race down posts and poles head first.  A whole flock has moved in, and Google isn't helping me with an introduction.  Steve used to complain that you have to know how to spell a word before you can find it in the dictionary; I feel the same way about looking up a bird on the internet.  It really doesn't matter in the long run.  I'll just enjoy the newcomers while they're here.  Odds are they will move on as quickly as they appeared.