What Am I?

On Sunday's hike at the Pony Pasture, a tiny bird flitted down in a tree's branches just a few feet away and spent a minute or two hopping from branch to branch.  I wondered what he was, and then he turned just the right way and I instantly knew.  See if you can guess.

In color I'm an olive green
In forests is where I am seen

In constant motion, I am quick
My wings I rapidly do flick

Despite my name I am no king
I have a white bar on my wing

Insects, spiders, bugs and such
Are what I eat (enjoy them much)

I said before that I'm no king
And that is true but here's the thing:

Just like a king I have a crown
Here's one last clue, then go to town -

A feathered patch of ruby red
Adorns the top of tiny head

I know this one might be kind of tough but that is all I can come up with for clues today.
So take your best guess
and
scroll
D
O
W
N
for the
answer!

Did you the answer run to ground?
I am a kinglet - ruby crowned!

With my digital camera, I was able to get a few photos of this tiny bird.  They are only around three or four inches long in total.  It came pretty close to me a few times.  I digitally zoomed in on the photos back at home.  The kinglet was in constant motion and it was hard to get photos.  Every time I located it in the viewfinder and was ready to press the button, it moved somewhere else.  After 30-45 seconds he climbed higher and higher in the tree and then flitted away.  Here, you can see the eye-ring, one of the field marks for this species.

On this photo, you can see the ruby patch that give him his name, and also its wing bar.