What Am I?

On my short nature hike last Monday along Donner Lake in the Sierra Nevada, I was fortunate enough to spot this quick and active creature flitting in and out of the rocks.  Can you guess what it is?

There is no doubt that I eat meat,
But not like deer - too big a feat

Nope, nothing large, I do proclaim,
For what I hunt is smaller game

Like chipmunks, and perhaps a mouse -
Why, I'll go right inside their house

For I am built quite long and lean,
And people think I'm kind of mean

But, hey, a fellow's got to eat
It's not my fault that I like meat!

I'm brown right now, but, what delight!
In winter I'll turn purest white

My tail, black tipped, is pretty long.
About me there's this catchy song

Here's one last clue before I stop -
Despite that song, I don't go "pop!"

Come on, you
got this one -
at least close
if not the exact species!
Scroll
D
O
W
N
and see
how you did....

Must I paint with brush and easel
For you to guess long tailed weasel?

We saw this weasel run across the path and disappear.  But we waited, and suddenly, he came back out and entertained us for a good 15 minutes.  He seemed curious but wary, and kept disappearing under rocks.  Then, he would pop out somewhere else after being out of sight.  It was a fascinating thing to watch - unless you are a chipmunk or mouse or small ground squirrel.  Then, it must be terrifying!