Garden thug

There's a hoodlum in your garden,
You're familiar with his name
You might never see it happen
But where there's trouble, he's to blame

He's the size of your hand
Fingers curled into a ball
He's challenged ev'ry bird in ev'ry garden
And ev'ry fight, he's won them all

I've seen him dive-bomb a crow
Threaten blackbirds, twice his size
Seen him tumble with his fellows
All fair game in his eyes

And after everything I've told you
I expect you will have guessed
That the terror I refer to
Is the one with the red breast.